View MAX5913_173054.PDF datasheet online --- IC-ON-LINE

Datasheet File OCR Text:

19-2244; Rev 2; 11/02
+48V Quad Hot-Swap Controllers For Power-Over-LAN
General Description
The MAX5913/MAX5914 are quadruple hot-swap controllers. The MAX5913/MAX5914 independently control four external N-channel switches to hot-swap system loads from a single VCC supply line. The devices allow the safe insertion and removal of power devices from live network ports. Operating supply voltage range is between +35V and +72V. The devices are intended for applications in Power-Over-Media-Dependent Interface (MDI), but are not limited to such usage. The MAX5913/MAX5914 feature an internal undervoltage lockout (UVLO) function that prevents the FET from turning on, if VCC does not exceed the default value of +32V. The devices also feature a +12V relay driver with 100mA current drive capable of driving low-voltage +3.3V relays. The MAX5913 features an active-low relay driver that sinks current when the relay output is enabled. The MAX5914 features an active-high relay driver output that sources 1mA to drive an external FET relay driver when the relay output is enabled. Control circuitry ensures the relays and the FETs are off until V CC reaches the UVLO threshold. The MAX5913/ MAX5914 use an external sense resistor to enable all the internal current-sense functions. The MAX5913/MAX5914 feature a programmable analog current-limit circuit. If the switch remains in current limit for more than a programmable time, the N-channel FET latches off and the supply can be restarted either by autoretry or by an external command after the preset off-time has elapsed. The MAX5913/MAX5914 are available in a 44-pin MQFP package and are specified for the extended -40C to +85C operating temperature range. o Wide Operating Input Voltage Range +35V to +72V o IEEE 802.3AF Compatible o Four Independent Power Switch Controllers o Open-Circuit Detector o On-Board Charge Pumps to Drive External N-Channel FETs o Current Sense with External Resistor o Foldback Current Limiting o +32V Input Undervoltage Lockout o On-Chip +12V, 100mA Voltage Relay Drivers
Features
MAX5913/MAX5914
Ordering Information
PART MAX5913EMH MAX5914EMH TEMP RANGE -40C to +85C -40C to +85C PIN-PACKAGE 44 MQFP 44 MQFP
Pin Configuration
RLYON4 ON3 RLYON3 ON2 RLYON2
38 37
44
43
42
VDD RTIM ON4
TOP VIEW
41
40
39
36
35
34
ON1 RLYON1 DC
Applications
Power-Over-LAN Power-Over-MDI IP Phone Switches/Routers Telecom Line Cards Network Switches/Routers Mid-Span Power-Over-MDI
FAULT STAT1 STAT2 STAT3 STAT4 CSP4 DRAIN4 OUT4 GATE4 CSP3 DRAIN3
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22
33 32 31 30 29
RTRYEN STATOUT OCEN DGND VCC CSP1 DRAIN1 GATE1 OUT1 CSP2 DRAIN2
MAX5913 MAX5914
28 27 26 25 24 23
OUT3 GATE3
VRLY RLYD3 RLYD4
DGND RLYD1 RLYD2
Typical Operating Circiut appears at end of data sheet.
MQFP ________________________________________________________________ Maxim Integrated Products 1
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at 1-888-629-4642, or visit Maxim's website at www.maxim-ic.com.
AGND OUT2 GATE2
+48V Quad Hot-Swap Controllers For Power-Over-LAN MAX5913/MAX5914
ABSOLUTE MAXIMUM RATINGS
VCC to AGND or DGND..........................................-0.6V to +76V DRAIN_, OUT_ to AGND or DGND................-0.6V to VCC +0.3V CSP_ to VCC ..........................................................-0.3V to +0.3V GATE_ to OUT_ .....................................................-0.3V to +13V VRLY to DGND ........................................................-0.3V to +18V RLYD_ to DGND........................................-0.3V to (VRLY + 0.3V) ON_, RLYON_, OCEN, RTRYEN, STATOUT, DC to DGND........................................................-0.3V to +12V FAULT to DGND .....................................................-0.3V to +12V STAT_, RTIM to DGND ...............................-0.3V to (VDD + 0.3V) VDD to DGND ...........................................................-0.3V to +7V DGND to AGND...........................................................-5V to +5V Current into RLYD_ .........................................-50mA to +150mA Current into Any Other Pin................................................50mA Continuous Power Dissipation (TA = +70C) 44-Pin MQFP (derate 12.7mW/C above +70C)......... 1.013W Operating Temperature Range ...........................-40C to +85C Storage Temperature Range .............................-65C to +150C Lead Temperature (soldering, 10s) ................................ +300C
Stresses beyond those listed under "Absolute Maximum Ratings" may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.
ELECTRICAL CHARACTERISTICS
(VCC = VCSP_ = +48V, AGND = DGND = 0, VDD = +3.3V, VRLY = +12V, TA = -40C to +85C, unless otherwise noted. Typical values are at VCC = VCSP_ = +48V and TA = +25C.)
PARAMETER POWER SUPPLIES Analog Supply Voltage Analog Supply Current Digital Supply Voltage Digital Supply Current Analog Supply Undervoltage Lockout UVLO Hysteresis UVLO Deglitch Delay Relay Driver Supply Ground Potential Difference VCC IS VDD IDD VUVLO VUVLO,H tD,UVLO VRLY VGG VON = 3.3V, VRLYON = 3.3V (Figure 1) Measured with respect to DGND Voltage difference between DGND and AGND -4 12.8 Measured with respect to AGND VCC = VCSP_ = 72V IS = ICC + ICSP 0C to +85C -40C to 0C 1.8 3.3 1.1 29 32 3 25.6 38.4 14 4 35 2.7 72 4 5 3.7 3 35 V mA V mA V V ms V V SYMBOL CONDITIONS MIN TYP MAX UNITS
Measured with respect to DGND All logic outputs high, RTIM floating VCC rising, circuits enabled
FEEDBACK INPUT AND CURRENT SENSE OUT Sense Bias Current Initial Feedback Voltage Current-Limit Threshold Voltage Foldback Voltage Fast Discharge Threshold Switch-On Threshold Switch-On Comparator Hysteresis MOSFET DRIVERS Gate Overdrive Voltage Gate Charge Current VGS IGATE VGATE - VCC when switch is fully on 0C to +85C -40C to 0C VGATE = 0 7 7 7 9 9 10 11 12 13 A V IFP VFB_S VSC VFLBK VFC VSWON VSWON_H Maximum VCC - VOUT at which the switch is defined as fully on, VOUT increasing VOUT_ = VCC Voltage under which the foldback circuit starts reducing the current-limit value (Note 1) Maximum V across RSENSE at VOUT > VFB_S Maximum V across RSENSE at VOUT = 0 125 42 360 1.2 18 142.5 48 420 1.5 160 160 54 480 1.8 2 A V mV mV mV V mV
2
_______________________________________________________________________________________
+48V Quad Hot-Swap Controllers For Power-Over-LAN
ELECTRICAL CHARACTERISTICS (continued)
(VCC = VCSP_ = +48V, AGND = DGND = 0, VDD = +3.3V, VRLY = +12V, TA = -40C to +85C, unless otherwise noted. Typical values are at VCC = VCSP_ = +48V and TA = +25C.) (Note 3)
PARAMETER Gate Discharge Current SYMBOL IGATE,DIS VON = 0 (VCSP_ - VDRAIN_) > VFC Source-Gate Clamp Voltage OPEN-CIRCUIT DETECTOR Open-Circuit Current-Threshold Voltage Delay to Open-Circuit Detect Deglitch Delay RELAY DRIVERS Maximum Low Voltage (MAX5913) Relay Pullup Current (MAX5914) Clamp Diode Voltage Relay Output Leakage TIMING Short-Circuit and Startup Timer (Note 2) tO RRTIM = 2k On time for continuous RRTIM = 40k overcurrent conditions RRTIM = DC = logic low Auto-Retry Duty Cycle Port Turn-ON Delay Relay Turn-OFF Delay DIGITAL INTERFACE DC Pin Input Voltage High DC Pin Input Voltage Low DC Pin Input Impedance Logic Input High Logic Input Low Logic Input Leakage FAULT Output Voltage Low FAULT High Input Leakage Logic Output Voltage High Logic Output Voltage Low VOH VOL STAT_ outputs sourcing 0.5mA STAT_ outputs sinking 0.5mA VDD - 0.4 0.4 VFL ISINK = 4mA VIH_DC VIL_DC RIN_DC VIH VIL +1.8V VDD +3.7V +1.8V VDD +3.7V 0.8 x VDD 0.3 x VDD 1 0.4 1 +1.8V VDD +3.7V +1.8V VDD +3.7V 1 0.7 x VDD 0.3 x VDD V V k V V A V A mV V tON_DEL tOFF_DEL DC = logic high DC = floating VON = 3.3V (Figure 3) After RLYON_ goes low (Figure 3) 12.8 1.6 4.8 76 3.2 6.4 128 6.4 1 2 4 25.6 3.2 38.4 4.8 ms ms % 8.0 180 9.6 ms VRLOW IRPLUP VRCLAMP RLYON = high, IRLYD_ = 100mA RLYON = high, VRLYD_ = 0 Force 100mA into RLYD, measure VRLYD VRLY RLYON_ = low, VRLYD_ = VRLY 1 0.3 0.8 0.5 1.3 2 V mA V A VOC tOC tLPFD Minimum V across RSENSE to detect an open circuit (Figure 2) (VCSP_ - VDRAIN__) < VOC (Figure 2) 1.5 450 106 3 900 204 4.5 1350 302 mV ms ms VSGZ VOUT_ = 0, force 30mA into GATE_, measure VGATE - VOUT 14 CONDITIONS During current regulation MIN TYP 8 1 15 16.5 18 MAX UNITS A mA mA V
MAX5913/MAX5914
Note 1: See Typical Operating Characteristics for Current-Limit Foldback, and refer to Current Sensing and Regulation section. Note 2: The resistor at RTIM can range from 2k to 40k. Note 3: Limits are 100% tested at TA = +25C and TA = +85C. Limits at -40C are guaranteed by design and characterization, but are not production tested. _______________________________________________________________________________________ 3
+48V Quad Hot-Swap Controllers For Power-Over-LAN MAX5913/MAX5914
Typical Operating Characteristics
(VCSP_ = VCC = +48V, VDD = +3.3V, VRLY = +12V, AGND = DGND = 0, RTIM = open, TA = +25C, unless otherwise specified.)
SUPPLY CURRENT vs. INPUT VOLTAGE
MAX5913/4 toc01
SUPPLY CURRENT vs. TEMPERATURE
MAX5913/4 toc02
UNDERVOLTAGE LOCKOUT vs. TEMPERATURE
MAX5913/4 toc03
4.0 3.8 3.6 SUPPLY CURRENT (mA) 3.4 3.2 3.0 2.8 2.6 2.4 2.2 2.0 TA = -40C TA = +85C
3.5 3.4 3.3 SUPPLY CURRENT (mA) 3.2 VCC = +48V VCC = +57V VCC = +72V
32
31 VCC RISING UVLO (V) 30 VCC FALLING
TA = +25C
3.1 3.0 2.9 2.8 2.7 2.6 2.5 -40 -15 10
29
28 VCC = +36V 27 35 60 85 -40 -15 10 35 60 85 TEMPERATURE (C) TEMPERATURE (C)
33 36 39 42 45 48 51 54 57 60 63 66 69 72 INPUT VOLTAGE (V)
GATE OVERDRIVE VOLTAGE vs. INPUT VOLTAGE
MAX5913/4 toc04
GATE OVERDRIVE VOLTAGE vs. TEMPERATURE
MAX5913/4 toc05
STARTUP WAVEFORMS
MAX5913/4 toc06
9.50 TA = -40C GATE OVERDRIVE (V) 9.25 TA = +25C
9.5 VCC = +57V GATE OVERDRIVE (V) VCC = +72V
A 0 0 B
9.0 VCC = +48V 8.5 VCC = +36V 0 C
9.00
8.75
TA = +85C 0 D
8.50 33 36 39 42 45 48 51 54 57 60 63 66 69 72 INPUT VOLTAGE (V)
8.0 -40 -15 10 35 60 85 4ms/div A: VON = VRLYON, 5V/div B: VRLYD, 20V/div C: VOUT, 20V/div D: VGATE, 20V/div TEMPERATURE (C)
TURN-OFF WAVEFORMS
MAX5913/4 toc07
GATE TURN-OFF WAVEFORM
MAX5913/4 toc08
UVLO TURN-ON DELAY
MAX5913/4 toc09
A 0 0 0 0 0 C C 0 0 0 D 4ms/div A: VON = VRLYON, 5V/div B: VRLYD, 20V/div C: VOUT, 20V/div D: VGATE, 20V/div A: VRLYD, 20V/div B: VRLYON, 5V/div C: VON, 5V/div D: VGATE, 20V/div 0 D 0 4ms/div RLYON = VDD A: VON, 5V/div B: VCC, 10V/div C: VOUT, 50V/div D: VGATE, 50V/div C D A B 0 A B 0 B
10ms/div
4
_______________________________________________________________________________________
+48V Quad Hot-Swap Controllers For Power-Over-LAN
Typical Operating Characteristics (continued)
(VCSP_ = VCC = +48V, VDD = +3.3V, VRLY = +12V, AGND = DGND = 0, RTIM = open, TA = +25C, unless otherwise specified.)
TURN-ON INTO CAPACITIVE LOAD (CL = 0.47F)
0
MAX5913/MAX5914
TURN-ON INTO CAPACITIVE LOAD (CL = 47F)
A 0 B C
MAX5913/4 toc10
MAX5913/4 toc11
TURN-ON INTO CAPACITIVE LOAD (CL = 470F)
A B C 0
MAX5913/4 toc12
A B C 0 0
0 0
0 0
0 400s/div RLYON = VDD A: VON, 5V/div B: VGATE, 20V/div C: VOUT, 20V/div D: IOUT, 100mA/div
D
0 1ms/div RLYON = VDD, RRTIM = 2k A: VON, 5V/div B: VGATE, 20V/div C: VOUT, 20V/div D: IOUT, 200mA/div
D
0 10ms/div RLYON = VDD, RRTIM = 40k A: VON, 5V/div B: VGATE, 20V/div C: VOUT, 20V/div D: IOUT, 200mA/div
D
CURRENT-LIMIT FOLDBACK (VCC = +36V)
0
CURRENT-LIMIT FOLDBACK (VCC = +48V)
A B 0
MAX5913/4 toc13
MAX5913/4 toc14
CURRENT-LIMIT FOLDBACK (VCC = +57V)
A B 0
MAX5913/4 toc15
A B
0 C 0 C 0 0 10ms/div RLYON = VDD, RL = 100, RRTIM = 40k, CLOAD = 470F A: VON, 5V/div B: VOUT, 10V/div C: IOUT, 200mA/div 0 0 10ms/div RLYON = VDD, RL = 139, RRTIM = 40k, CLOAD = 470F A: VON, 5V/div B: VOUT, 10V/div C: IOUT, 200mA/div 10ms/div RLYON = VDD, RL = 162, RRTIM = 40k, CLOAD = 470F A: VON, 5V/div B: VOUT, 10V/div C: IOUT, 200mA/div C
_______________________________________________________________________________________
5
+48V Quad Hot-Swap Controllers For Power-Over-LAN MAX5913/MAX5914
Typical Operating Characteristics (continued)
(VCSP_ = VCC = +48V, VDD = +3.3V, VRLY = +12V, AGND = DGND = 0, RTIM = open, TA = +25C, unless otherwise specified.)
CURRENT-LIMIT FOLDBACK (VCC = +72V)
0
MAX5913/4 toc16
CURRENT-LIMIT FOLDBACK (VCC = +57V)
MAX5913/4 toc17
CURRENT-LIMIT FOLDBACK (VCC = +72V)
A B 0
MAX5913/4 toc18
A B 0
A B
0 0 C 0
0 10ms/div RLYON = VDD, RL = 200, RRTIM = 40k A: VON, 5V/div B: VOUT, 10V/div C: IOUT, 200mA/div
0 10ms/div RLYON = VDD, RL = OPEN, RRTIM = 40k, CLOAD = 470F A: VON, 5V/div B: VOUT, 10V/div C. IOUT, 200mA/div
C
0 20ms/div
C
RLYON = VDD, RL = OPEN, RRTIM = 40k, CLOAD = 470F A: VON, 5V/div B: VOUT, 20V/div C: IOUT, 200mA/div
OVERCURRENT DELAY
MAX5913/4 toc19
OVERCURRENT DELAY (EXPANDED TIME SCALE)
MAX5913/4 toc20
SHORT-CIRCUIT RESPONSE (VCC = +48V)
MAX5913/4 toc21
A A 0 0 0
A
B 0 0 20ms/div RTRYEN = VDD, RLYON = ON = VDD, DC = 4%, RRTIM = 2k, RL = 100 A: VGATE, 20V/div B: IOUT, 200mA/div 1ms/div RTRYEN = VDD, RLYON = ON = VDD, DC = DON'T CARE, RRTIM = 2k, RL = 100 A: VGATE, 20V/div B: IOUT, 200mA/div B 0 1ms/div ON = RLYON = VDD, RL = 1, RRTIM = 2k A: IOUT, 200mA/div B: VGATE, 20V/div
B
6
_______________________________________________________________________________________
+48V Quad Hot-Swap Controllers For Power-Over-LAN
Typical Operating Characteristics (continued)
(VCSP_ = VCC = +48V, VDD = +3.3V, VRLY = +12V, AGND = DGND = 0, RTIM = open, TA = +25C, unless otherwise specified.)
SHORT-CIRCUIT RESPONSE (VCC = +48V EXPANDED TIME SCALE)
MAX5913/4 toc22
MAX5913/MAX5914
PEAK SHORT-CIRCUIT RESPONSE (VCC = +48V EXPANDED TIME SCALE)
MAX5913/4 toc23
SHORT-CIRCUIT RESPONSE (VCC = +57V)
MAX5913/4 toc24
A A 0 0 A 0
B B 0 40s/div ON = RLYON = VDD, RL = 1, RRTIM = 2k A: IOUT, 200mA/div B: VGATE, 20V/div B 0 1s/div ON = RLYON = VDD, RL = 1, RRTIM = 2k A: IOUT, 5A/div B: VGATE, 20V/div ON = RLYON = VDD A: IOUT, 200mA/div B: VGATE, 20V/div 0 1ms/div
SHORT-CIRCUIT RESPONSE (VCC = +57V, EXPANDED TIME SCALE)
MAX5913/4 toc25
PEAK SHORT-CIRCUIT RESPONSE TIME (VCC = +57V, EXPANDED TIME SCALE)
MAX5913/4 toc26
SHORT-CIRCUIT RESPONSE (VCC = +72V)
MAX5913/4 toc27
A A A 0 0 0
B B 0 40s/div ON = RLYON = VDD, RL = 1, RRTIM = 2k A: IOUT, 200mA/div B: VGATE, 20V/div B 0 1s/div ON = RLYON = VDD, RL = 1, RRTIM = 2k A: IOUT, 5A/div B: VGATE, 20V/div ON = RLYON = VDD A: IOUT, 200mA/div B: VGATE, 50V/div 1ms/div 0
_______________________________________________________________________________________
7
+48V Quad Hot-Swap Controllers For Power-Over-LAN MAX5913/MAX5914
Typical Operating Characteristics (continued)
(VCSP_ = VCC = +48V, VDD = +3.3V, VRLY = +12V, AGND = DGND = 0, RTIM = open, TA = +25C, unless otherwise specified.)
SHORT-CIRCUIT RESPONSE (VCC = +72V, EXPANDED TIME SCALE)
MAX5913/4 toc28
PEAK SHORT-CIRCUIT RESPONSE TIME (VCC = +72V, EXPANDED TIME SCALE)
MAX5913/4 toc29
OPEN-CIRCUIT THRESHOLD vs. INPUT VOLTAGE
3.8 THRESHOLD VOLTAGE (mV) 3.6 3.4 3.2 3.0 2.8 2.6 2.4 2.2 2.0 TA = -40C TA = +25C
MAX5913/14 toc30
4.0 TA = +85C
A 0 0
A
B 0 40s/div ON = RLYON = VDD, RL = 1, RRTIM = 2k A: IOUT, 200mA/div B: VGATE, 50V/div 0 1s/div ON = RLYON = VDD, RL = 1, RRTIM = 2k A: IOUT, 5A/div B: VGATE, 50V/div
B
33 36 39 42 45 48 51 54 57 60 63 66 69 72 INPUT VOLTAGE (V)
OPEN-CIRCUIT THRESHOLD vs. TEMPERATURE
MAX5913/14 toc31
OPEN-CIRCUIT GLITCH DELAY
MAX5913/4 toc32
tO vs RRTIM
MAX5913/4 toc33
4.0
120 100 80 TA = -40C, +25C, +85 C
THRESHOLD VOLTAGE (mV)
3.5
0
A
3.0 VCC = +36V, +48V, +57V, AND +72V
0
tO (ms)
B
60 40
2.5
C 0 -40 -15 10 35 60 85 40ms/div ON = RLYON = VDD, STATOUT = LOW A: IOUT, 20mA/div B: VSTAT, 5V/div C: VGATE, 20V/div TEMPERATURE (C)
20 0 0 5 10 15 20 25 30 35 40 RRTIM (k)
2.0
8
_______________________________________________________________________________________
+48V Quad Hot-Swap Controllers For Power-Over-LAN
Typical Operating Characteristics (continued)
(VCSP_ = VCC = +48V, VDD = +3.3V, VRLY = +12V, AGND = DGND = 0, RTIM = open, TA = +25C, unless otherwise specified.)
MAX5913/MAX5914
to vs. INPUT VOLTAGE
125 100 tO (ms) 75
MAX5913/4 toc34
RETRY DUTY CYCLE vs. DC
MAX5913/4 toc35
CHANNEL-TO-CHANNEL CROSSTALK
MAX5913/4 toc36
RRTIM = 40k 0
A
VTEST 5V/div
B 50 25 0 1.8 2.1 2.4 2.7 VDD (V) 3.0 3.3 3.6 100ms/div VGATE = 20V/div, RRTIM = 2k A: VGATE, 20V/div, DC = FLOATING (4%) B: VGATE, 20V/div, DC = VDD (2%) C: VGATE, 20V/div, DC = GND (1%) 20s/div SEE FIGURE 4 FOR TEST CIRCUIT RRTIM = OPEN RRTIM = 2k 0 0 C VOUT 10mV/div
Pin Description
PIN NAME FUNCTION Fault Output. FAULT is an open-drain output that goes low when a fault is detected on any of the four channels. FAULT is low when an OC (open circuit) is detected, or when the MAX5913/MAX5914 is in auto-retry caused by an overcurrent condition. When RTRYEN is low, and the channel switch is latched off due to overcurrent condition, FAULT remains low until ON_ is driven low. Status Outputs. STAT_ are push-pull outputs. Depending on the STATOUT pin status, STAT_ flags either the Power-OK_ or Port-OC_ status. Power-OK_ high indicates: a) ON_ input is high b) The switch port is fully on and startup is completed (VCSP_ - VOUT_) < VSWON c) Input voltage is above VUVLO d) Switch is not in current limit. Power-OK_ low indicates a fault with any of the above conditions. Port-OC_ output high indicates that the switch is latched off because the switch current is less than the open current threshold Port-OC is low otherwise. Current-Sense Positive Input. Connect to VCC and place a current-sense resistor from CSP_ to DRAIN_. Use Kelvin sense trace from current-sense resistor to CSP_ (see Figure 7). MOSFET Drain Current-Sense Negative Input. Connect to drain of power MOSFET and connect a current-sense resistor from CSP_ to DRAIN_. Use Kelvin sense trace from current-sense resistor to DRAIN_ (see Figure 7).
1
FAULT
2, 3, 4, 5
STAT1, STAT2, STAT3, STAT4
6, 10, 24, 28
CSP4, CSP3, CSP2, CSP1 DRAIN4, DRAIN3, DRAIN2, DRAIN1
7, 11, 23, 27
_______________________________________________________________________________________
9
+48V Quad Hot-Swap Controllers For Power-Over-LAN MAX5913/MAX5914
Pin Description (continued)
PIN 8, 12, 21, 25 NAME OUT4, OUT3, OUT2, OUT1 GATE4, GATE3, GATE2, GATE1 VRLY RLYD3, RLYD4, RLYD1, RLYD2 DGND AGND FUNCTION MOSFET Source Output Voltage Sense. Connect to power MOSFET source through a 100 series resistor. MOSFET Gate Driver Output. The MAX5913/MAX5914 regulate the gate-drive voltage to (VCC + 9V) to fully turn on the power N-channel MOSFET. GATE_ sources 10A during startup to slowly turn-on the MOSFET switch. GATE_ sinks 1mA to turn-off the MOSFET switch. Relay Supply Voltage Input. Referenced to DGND. Relay-Drive Output. For the MAX5913, RLYD_ sinks 100mA when the relay driver is enabled. For the MAX5914, RLYD_ sources 1mA when the relay driver is enabled. Digital Ground. All logic voltages are referred to DGND. The voltage difference between DGND and AGND can be up to 4V. Analog Ground. All analog voltages are referred to AGND. Analog Power Supply. Connect VCC to +35V to +72V power supply. UVLO circutry turns off MOSFET switch and relay for VCC < VUVLO. Bypass VCC to AGND with a 1F capacitor. Open-Circuit Detector Enable Input. Drive OCEN high to enable open-circuit detector, or drive low to disable. When enabled, the open-circuit detector waits for a 900ms delay after Power-OK conditions are met before enabling the open-circuit detector function. Status Output Multiplexer (MUX) Control Input. Controls the signal MUX into the STAT_ outputs. Drive STATOUT high to route Power-OK_ status to STAT_ outputs, or drive STATOUT low to route Port-OC_ status to STAT_ outputs. Auto-Retry Enable Input. Drive RTRYEN high to enable auto-retry. Drive RTRYEN low to enable switch latch-off mode. When switch is latched off, a high-to-low transition on the ON_ control input clears the latch. Duty-Cycle Programming Input. DC sets the minimum off-time after an overcurrent condition latches off the switch. When RTRYEN is high, DC sets the auto-retry duty cycle. Drive DC low for 1% duty cycle, drive DC high for 2%, or leave DC floating for 4% duty cycle. Relay-Driver Control Input. Drive RLYON_ high to enable RLYD_, drive RLYON_ low to turn off MOSFET switch for the channel and disable RLYD_. MOSFET Switch Control Input. Drive ON_ high to enable GATE_ to turn on MOSFET switch. RLYON_ must be high to enable the switch. Drive ON_ low to disable the switch. Pulling ON_ low also resets the latch when RTRYEN is low or if the switch is latched off due to open-circuit detection. Timing Oscillator Frequency Set Input. Connect a 2k to 40k resistor from RTIM to DGND to set the maximum continuous overcurrent time, tO. Leave RTIM unconnected to set default 6.4ms tO. Digital Power Supply. Bypass VDD to DGND with a 1F capacitor.
9, 13, 22, 26
14 15, 16, 18, 19 17, 30 20
29
VCC
31
OCEN
32
STATOUT
33
RTRYEN
34
DC
35, 37, 39, 41 36, 38, 40, 42
RLYON1, RLYON2, RLYON3, RLYON4 ON1, ON2, ON3, ON4
43 44
RTIM VDD
10
______________________________________________________________________________________
+48V Quad Hot-Swap Controllers For Power-Over-LAN
Detailed Description
The MAX5913/MAX5914 quadruple hot-swap controllers provide Power-Over-MDI, also known as Power-OverLAN systems (Figure 5). The MAX5913/MAX5914 enable control of four external N-channel MOSFET switches from a single VCC ranging from +35V to +72V, with timing control and current-limiting functions built in. Features include undervoltage lockout (UVLO), 100mA relay drivers, dual-level current sense, foldback current limit, programmable overcurrent time and auto-retry periods, internal charge pumps to drive external MOSFET and soft-start, port status output indicating PowerOK or open-circuit conditions (Figure 6). VOUT I = GATE t CGATE If a capacitor load is connected to the output the total current through the FET is: I = IGATE CL CGATE + IL
MAX5913/MAX5914
where CL is the load capacitance and IL is the current required by any load connected to the output during the startup phase. If the current through the FET reaches the programmed current-limit value: IMAX = VSC RSENSE
Switch and Relay Control Inputs
The MAX5913/MAX5914 ON_ inputs turn on the corresponding MOSFET switch. Driving ON_ high turns on the switch if the corresponding RLYON is driven high, and V CC > V UVLO for more than 25.6ms. Driving RLYON_ high immediately turns on the corresponding relay, and activates the 25.6ms delay after which the corresponding ON_ input is active. Driving RLYON_ low immediately turns off the switch and activates a 3.2ms delay after which the relay is turned off. These internal delays safely allow driving ON_ and RLYON_ simultaneously. The relay is turned on while the switch is off so that there is no voltage across the relay contacts. The relay is turned off while the switch is off so that there is no current flowing when the relay contacts are opened (see Figure 3).
the internal current-limit circuitry activates and regulates this FET current to be a value, ILIM, that depends on VOUT (IFLBK) (Figure 8). See the Current Sensing and Regulation section for more information. In this case the maximum rate of change of the output is determined by: VOUT ILIM - IL = t CL The formula shows the necessity for ILIM to be larger than IL in order to allow the output voltage to rise. The foldback function is active as long as the circuit is in overcurrent condition. Should the overcurrent condition persist for a period longer than the maximum time tO, the switch is latched off and GATE_ is discharged to ground with a 1mA pulldown current. If auto-retry is enabled, the switch turns on again after a waiting period, tOFF, which is determined by the programmed duty cycle. After the startup, the internal charge pumps provide (VCC + 9V) typical gate overdrive to fully turn on the switch. When the switch is fully on (voltage drop across the switch is 1.5V), and the switch is not in current limit, the Power-OK signal is asserted.
Input Voltage and UVLO
The MAX5913/MAX5914 operate from +35V to +72V supply voltage. VCC powers the MAX5913/MAX5914 analog circuitry and is monitored continuously during startup and normal operation. The MAX5913/MAX5914 keep all MOSFET switches and relay drivers securely off before V CC rises above V UVLO . The MAX5913/ MAX5914 turn off all MOSFET switches and relay drivers after VCC falls below VUVLO - VUVLO,H.
Startup
When the turn-on condition is met (see Input Voltage and UVLO and Switch and Relay Control Inputs sections), the MAX5913/MAX5914 slowly turn on the external MOSFET switch by charging its gate using a constant current source, IGATE (10A typ). The gate voltage slope is determined by the total gate capacitance CGATE connected to this node. Since the output voltage follows the gate voltage, thus the output rises with a slope determined by:
Current Sensing and Regulation
The MAX5913/MAX5914 control port current with using two voltage comparators (dual-level detection) that sense the voltage drop across an external currentsense resistor. Connect CSP_ to VCC and connect a current-sense resistor between CSP_ and DRAIN_. Kelvin sensing should be used as shown in Figure 7.
11
______________________________________________________________________________________
+48V Quad Hot-Swap Controllers For Power-Over-LAN MAX5913/MAX5914
Test Circuits and Timing Diagrams
(VCC - VOUT) 1.5V (POWER-OK IS GOOD)
VCC
VUVLO
VCC
OC DETECTOR ENABLED (INTERNAL SIGNAL) VGATE +1V tD, UVLO VGATE tOC +1V
tLPFD
Figure 1. UVLO Deglitch Delay
Figure 2. Open-Circuit Detector Deglitch Delay
0.33
200
470F
RLYON
VIH VIL
270F 100 VTEST
CSP1
DRAIN1 GATE1 OUT1 ON1 RLYON1
VGATE +1V tON_DEL tOFF_DEL VRLY RLYD (MAX5913)
270F CSP2 +42V VCC 270F 270F MAX5913/MAX5914
ON2 RLYON2 DRAIN2 GATE2 OUT2 DGND 100 0.33 VOUT 3.3V
Figure 3. Port Turn-On Delay, Relay Turn-Off Delay
Figure 4. Channel-to-Channel Crosstalk Test Circuit
The first comparator compares the sensed voltage against VSC threshold (typically 142.5mV). Choose a sense resistor as follows: RSENSE = VSC / IMAX where IMAX is the maximum current allowed through the switch. When IMAX is reached, foldback current-limit circuitry regulates the current limit as a function of VOUT (Figure 8). As VOUT approaches zero the maximum voltage
12
drop across the sense resistor is lowered to a minimum value of 48mV (typ). This foldback feature helps reduce the power dissipation in the external power FET during output overload and output short-circuit conditions. If a load with very low activation voltage is permanently connected to the output, make the minimum limit current sufficiently larger than the load current. If the load current indeed exceeds the foldback-limit value the MAX5913/MAX5914 are not able to power-up the switch.
______________________________________________________________________________________
+48V Quad Hot-Swap Controllers For Power-Over-LAN MAX5913/MAX5914
VCC = +35V TO +72V 1.0F
DIGITAL INTERFACE INPUTS
ON1 ON2 ON3 ON4 RLYON1 RLYON2 RLYON3 RLYON4 OCEN RTRYEN STATOUT DC
VCC
CSP1 0.33 DRAIN1 GATE1 OUT1 100 FDT3612 N NO PORT 1
MAX5913 VRLY
K1
+12V +3.3V 1F 1k
VRLY VDD VCC CSP4 FAULT 0.33 DRAIN4 GATE4 OUT4 RTIM 100 K4 FDT3612 N NO PORT 4
DIGITAL INTERFACE OUTPUTS
STAT1 STAT2 STAT3 STAT4
2k DGND AGND RLYD1 RLYD4
VRLY
Figure 5. Typical Application Circuit
A second comparator with a detection threshold of 3VSC activates a fast 15mA pulldown of the gate. The purpose of this comparator is to rapidly discharge the gate when a momentary current peak overstresses the external FET helping the regulation to act more rapidly. The sense resistor is also used to detect an open-circuit or low-current condition with a typical threshold of 3mV.
Open-Circuit Detection
The MAX5913/MAX5914 detect when a port has low current or is open circuit, and turn off the switch to that port. After the switch is turned on and the Power-OK conditions are met, the open-circuit detector is enabled
after a 900ms delay. The open-circuit voltage threshold is set at 3mV across the current-sense resistor. Drive OCEN high to enable open-circuit detectors for all four ports. Drive OCEN low to disable the detectors. Each port has an open-circuit flag that can be read from STAT_ outputs when the STATOUT is low. STAT_ output high indicates that the switch is latched off due to an open-circuit condition on that port. To reset the latch pull ON_ low and then high to restart (Table 1).
Output Voltage Sense and Power-OK
The MAX5913/MAX5914 sense the output voltage of the port at the source of the external MOSFET switch.
______________________________________________________________________________________
13
+48V Quad Hot-Swap Controllers For Power-Over-LAN MAX5913/MAX5914
RTRYEN DC CSP 420mV 142.5mV 3mV RSENSE FROM LOGIC CONTROLLER DUAL LEVEL DETECTION FOLDBACK NL CONTROL DC COUNTER RESET LOGIC UVLO TIMING OSCILLATOR DRAIN CHARGE PUMP 10A GATE VDD OUT TO LOGIC OPEN-CIRCUIT CONTROLLER DETECTOR 1mA CSP -1.5V POK COMPARATOR LOGIC CONTROLLER VDD 8A 1mA VRLY RELAY CONTROL 1.236V RTIM VCC
DGND DELAY OCEN AGND DGND ON RLYON RLYD
Figure 6. Functional Diagram
Internally the circuit compares the output voltage with VCC to determine when the FET is completely on. A "Power-OK" condition is met when: (VCC - VOUT) 1.5V The internal circuit monitors V OUT to determine the value of the foldback current when the circuit goes into current-limit conditions. The value of the current limit decreases as the output voltage decreases in order to limit the power dissipation of the FET. The nonlinear relationship between V OUT and I LIM is depicted in Figure 8. The foldback circuit is active whenever the MAX5913/ MAX5914 is in current-limit mode after an overcurrent condition has been detected.
Connect a catch diode to analog ground and a 100 resistor in series with OUT_ to limit the current during negative inductive kicks that can bring OUT_ below the ground potential (Figure 5).
Relay Drivers
The MAX5913/MAX5914 include on-chip relay drivers, RYLD_, capable of sinking 100mA. When RLYON_ goes high the MAX5913/MAX5914 immediately enable the relay driver, and the corresponding ON_ switch control input is delayed 25.6ms to allow the relay to close under a zero-voltage condition. When RLYON_ goes low, the MAX5913/MAX5914 immediately turn off the corresponding switch, and then turn off the relay driver after a 3.2ms delay, ensuring the relay contacts open under a zero-current condition. The polarity of the
14
______________________________________________________________________________________
+48V Quad Hot-Swap Controllers For Power-Over-LAN
MAX5913 RLYD_ is opposite to that of the MAX5914. For the MAX5913, upon the assertion of the RLYON_ input RLYD_ sinks 100mA to DGND. For the MAX5914 when RLYON_ is high, an internal 1mA current source pulls up RLYD_ to VDD. A 100mA catch diode is internally connected between RYLD_ and VRLY to protect the MAX5913/MAX5914 from inductive kicks from the relay coil. VRLY must be connected to the high-side relay supply voltage. However, the MAX5913/MAX5914 always waits a minimum time tOFF, before restarting the switch.
MAX5913/MAX5914
Logic Interface and Status Outputs
The MAX5913/MAX5914 logic interface controls the device functionality. All the basic control functions for the four switches are separated. ON_ enables individual on/off control of each MOSFET (the corresponding relay must be on to turn on the switch). RLYON_ enables individual on/off control of each relay. STAT_ indicates Power-OK or Port-OC (open circuit) status of each switch. The other logic pins are common to all four switches. A single FAULT output goes low when any of the four channels is latched off. Driving OCEN high enables the open-circuit detectors. Driving RTRYEN high enables the auto-retry function, RTRYEN low enables the switch latch-off function. DC, a three-level logic input, programs the duty cycle. The STATOUT input selects the signal multiplexed at STAT_ outputs (Table 1.). Driving STATOUT high routes Power-OK status to the STAT_ outputs. Driving STATOUT low routes Port-OC status to the STAT_ outputs.
Programmable Timing, RTIM
An external resistor from RTIM to DGND sets the frequency of the internal oscillator upon which tO and the auto-retry times are based. Use 2k to 40k resistors for RRTIM. tO = (RRTIM / 2k) (6.4ms) If RTIM is unconnected (floating), an internal resistor sets tO to a nominal 6.4ms.
Auto-Retry and Programmable Duty Cycle
The MAX5913/MAX5914 feature auto-retry with adjustable duty cycle. Driving RTRYEN high enables the auto-retry function. When the switch encounters an overcurrent for a period greater than tO the switch is turned off, and remains off for a tOFF programmed by DC, a three-level input. After the tOFF period, the switch is automatically turned on again. When the port encounters a continuous overload or short-circuit condition, the switch turns on and off repeatedly with the on duty cycle of 1%, 2%, or 4% depending on the DC input state (Table 2). When RTRYEN is low, the autoretry is disabled, and a fault condition at the switch turns the switch off and the switch remains latched off. Driving the corresponding ON control input low resets the latch. Pulling ON high to turn on the switch.
Fault Management
UVLO and Power-OK The MAX5913/MAX5914 monitor the VCC input voltage and each switch's current and voltage to determine Power-OK, overcurrent, or Port-OC status. When VCC falls below the UVLO threshold, FAULT goes low and all four switches and relays are turned off. When the volage across the switch is less than 1.5V, the switch is fully on, and if the switch is not in current limit or open circuit, Power-OK status is good (high). Open-Circuit Faults With the open circuit detector enabled, when any switch current falls below the open-circuit detector
Table 1. Status Output
PORT_ CONDITION Enabled. Switch fully on and not in current limit Enabled. Switch in current limit, or VDS > 1.5V Enabled. Switch current is less than OC threshold, port is latched off Enabled. Switch fully on and output current is greater than OC threshold Disabled OCEN x x H H L STATOUT H H L L L STAT_ H (Power-OK_ is good) L (Power-OK_ is not good) H (Port-OC_ , Port current is low or zero) L (Port-OC_ , Port current is good) L
______________________________________________________________________________________
15
+48V Quad Hot-Swap Controllers For Power-Over-LAN MAX5913/MAX5914
threshold current, the open-circuit detector turns off the switch after a 25.6ms delay, FAULT goes low and the Port-OC flag is set for that switch. To clear the switch latched-off condition, FAULT and Port-OC flags drive the corresponding ON input low. Overcurrent Faults When an on switch current exceeds the current-limit threshold, foldback circuitry activates and regulates the switch current. When current limit lasts for longer than tO, the switch latches off. The Power-OK status flag is set low, and the FAULT flag is set. If auto-retry is enabled, the switch remains off for a period tOFF. If auto-retry is disabled, the switch remains latched off, and FAULT is low. Reset the latch and FAULT by driving corresponding ON_ low. on during large output load-current transients. The smaller the tO, the faster the MAX5913/MAX5914 turn off the external FET in case of output overload or short-circuit condition. 2) For startup with current limit, when CL VSC I = IGATE + IL CGATE RSENSE which is expected when CL CGATE is large, tO must be set to be long enough to allow the output voltage to rise and settle before tO elapses. In this case, tO must satisfy the following equation: t O = CL 18 V - 18V + CL CC 2 IMAX - IL IMAX - IL 3
Applications Information
Considerations for circuit design include output capacitor requirements, current-limit requirements, setting the maximum on-time in current limit, and choosing a suitable MOSFET and on-time duty cycle in auto-retry.
Output Capacitor Requirements
The load capacitor requirements should be determined first, as this affects the required startup.
where VCC is the input voltage and given that IL < ILIM.
Choosing Power MOSFET
The FET must withstand a short-circuit condition where its power dissipation is PDISS = VCC ILIM. The FET must have sufficient thermal capacitance to prevent thermal heating damage during the tO time.
Current-Limit Requirements (Choosing RSENSE)
The current limit should be set to at least 20% higher than the expected full load current. If current limit is also used to control startup current, then set this limit high enough so that the output voltage can rise and settle before tO elapses (see Setting tO section below).
Choose Duty Cycle (setting DC)
The duty cycle can be adjusted to allow time for heat to dissipate between tO cycles, allowing use of smaller MOSFETs with lower thermal capacitance. For smaller duty cycle, a smaller FET is sufficient. See Table 2 for setting the duty cycle. The auto-retry off-time should not be too long to keep system wait time during retry period to a reasonable value. For example, when tO is set to 128ms and duty cycle is set to 1%, the retry time is 99 128ms = 12.7s.
Setting tO (Choosing RRTIM) Choose the tO time by connecting a 2k to 40k resistor from RTIM to DGND. The minimum 6.4ms tO is set with RRTIM = 2k. The maximum 128ms tO is set with RRTIM = 40k set according to the following equation: tO = (RRTIM / 2k) (6.4ms). tO should be chosen appropriately, depending on the startup condition. There are two cases: 1) For startup without current limit, when
I = IGATE CL VSC + IL < CGATE RSENSE
Application Circuits
In a typical LAN system there are two ways to deliver power over the LAN cable. Power can be supplied to the unused cable pairs, or power can be supplied over the signal pairs (Figures 9 and 10).
the startup current does not reach the maximum current-limit threshold and tO will not activate during startup condition. In this case, set t O to a small value, but large enough to allow the switch to remain
16
______________________________________________________________________________________
+48V Quad Hot-Swap Controllers For Power-Over-LAN MAX5913/MAX5914
HIGH-CURRENT PATH
ILIM
SENSE RESISTOR
IMAX =
VSC RSENSE
DRAIN_
CSP_
IMAX /3
MAX5913 MAX5914
0
18V
VOUT
Figure 7. Recommended Layout for Kelvin-Sensing Current Through Sense Resistor
Figure 8. Foldback Current-Limit Response
Table 2. Duty Programming Cycle
DC 0 1 Open tOFF 99 tO 49 tO 24 tO DUTY CYCLE 1% 2% 4%
______________________________________________________________________________________
17
+48V Quad Hot-Swap Controllers For Power-Over-LAN MAX5913/MAX5914
LAN SWITCH N +48V POWER OVER SIGNAL PAIRS RJ45 +48V OUT DATA CAT 5 RJ45 PD MAX5913 MAX5914 POWERED DEVICE (IP PHONE, ETC.)
+48V
Figure 9. Power Sent Over Signal Pairs
MIDSPAN HUB RJ45 RJ45 CAT 5 N +48V OUT RJ45
+48V POWER OVER SPARE PAIRS RJ45 PD CAT 5 POWERED DEVICE (IP PHONE, ETC.)
+48V MAX5913 MAX5914
Figure 10. Power Sent Over Spare Pairs
Chip Information
TRANSISTOR COUNT: 14,622 PROCESS: BiCMOS
18
______________________________________________________________________________________
+48V Quad Hot-Swap Controllers For Power-Over-LAN
Typical Operating Circuit
VCC = +35V TO +72V VCC CSP1
MAX5913/MAX5914
DIGITAL INTERFACE INPUTS
ON1 ON2 ON3 ON4 RLYON1 RLYON2 RLYON3 RLYON4 OCEN RTRYEN STATOUT DC
DRAIN1 GATE1 OUT1 MAX5913 VRLY N PORT 1
+12V +3.3V
VRLY VDD VCC CSP4 FAULT
DIGITAL INTERFACE OUTPUTS
STAT1 STAT2 STAT3 STAT4 GATE4 OUT4 RTIM VRLY N PORT 4 DRAIN4
DGND
AGND
RLYD1
RLYD4
______________________________________________________________________________________
19
+48V Quad Hot-Swap Controllers For Power-Over-LAN MAX5913/MAX5914
Package Information
(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information, go to www.maxim-ic.com/packages.)
MQFP44.EPS
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.
20 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 (c) 2002 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.

▲Up To Search▲

Price & Availability of MAX5913

	To Download MAX5913 Datasheet File
If you can't view the Datasheet, Please click here to try to view without PDF Reader .