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MIC2546/2547 Micrel MIC2546/2547 Dual Programmable Current Limit Switch Preliminary Information General Description The MIC2546 and MIC2547 are integrated high-side dual power switches optimized for low loss dc power switching and other power management applications, including Advanced Configuration and Power Interface (ACPI). The MIC2546/47 is a cost-effective, highly integrated solution that requires few external components to satisfy USB and ACPI requirements. Load current management features include a precision resistor-programmable output current-limit and a soft-start circuit which minimizes inrush current when the switch is enabled. Thermal shutdown, along with current-limit, protects the switch and the attached device. The MIC2546/47's open-drain flag outputs are used to indicate current-limiting or thermal shutdown to a local controller. The MIC2547 has an additional internal latch which turns the output off upon thermal shutdown providing robust fault control. The enable signal is compatible with both 3V and 5V logic, and is also used as the thermal shutdown latch reset for the MIC2547. The MIC2546 and MIC2547 are available in active-high and active-low enable versions in 16-pin TSSOP and SOP packages. Features * * * * * * * * * * * * * * * * * * 2.7V to 5.5V input Adjustable current-limit up to 1.5A Reverse current flow blocking (no "body diode") 100A typical on-state supply current per channel 2A typical off-state supply current 120m maximum on-resistance Open-drain fault flag Thermal shutdown Thermal shutdown output latch (MIC2547) 2ms (slow) turn-on and fast turnoff Available with active-high or active-low enable USB power distribution PCI Bus Power Switching Notebook PC ACPI power distribution PC card hot swap applications Inrush current-limiting Ideal for dual supply applications Applications Typical Application +5V 0.1F RFLGA MIC2546-xBM On/Off ENA FLGA GNDA OUTA INA OUTA NC OUTB INB OUTB NC 33F Peripheral 33F Peripheral RSETA ILIMA On/Off ENB FLGB RFLGB GNDB ILIMB RSETB +3.3V 0.1F Typical Advanced Configuration and Power Interface (ACPI) Application Micrel, Inc. * 1849 Fortune Drive * San Jose, CA 95131 * USA * tel + 1 (408) 944-0800 * fax + 1 (408) 944-0970 * http://www.micrel.com June 2000 1 MIC2546/2547 MIC2546/2547 Micrel Ordering Information Part Number MIC2546-1BM MIC2546-1BTS MIC2546-2BM MIC2546-2BTS MIC2547-1BM MIC2547-1BTS MIC2547-2BM MIC2547-2BTS Enable Active High Active High Active Low Active Low Active High Active High Active Low Active Low * * * * Latch* Temperature Range -40C to +85C -40C to +85C -40C to +85C -40C to +85C -40C to +85C -40C to +85C -40C to +85C -40C to +85C Package 16-pin SOP 16-pin TSSOP 16-pin SOP 16-pin TSSOP 16-pin SOP 16-pin TSSOP 16-pin SOP 16-pin TSSOP * Thermal Shutdown Latch Pin Configuration MIC2546/2547 INA 1 OUTA 2 ENA 3 NC 4 FLGA 5 GNDB 6 ILIMB 7 OUTB 8 16 OUTA 15 ILIMA 14 GNDA 13 FLGB 12 ENB 11 OUTB 10 NC 9 INB (ILIMB) (GND) (ENA) (FLGA) (ILIMA) (ENB) (FLGB) LOGIC, CHARGE PUMP MIC2546/2547 LOGIC, CHARGE PUMP (OUTA) (INA) (OUTB) (INB) Functional Pinout 16-Pin SOP (M) 16-Pin TSSOP (TS) Pin Description Pin Number 1 2, 16 3 Pin Name INA OUTA ENA Pin Function Input A: Output A MOSFET drain. Also supplies internal circuitry. Switch A (Output): Output A MOSFET source. Pins 2 and 16 must be externally connected. Enable A (Input): Logic-compatible enable input. Active-high (-1) or activelow (-2). High input >1.7V typical; low input <1.5V typical. Do not float. MIC2547 only: Also resets thermal shutdown latch. Not internally connected. Fault Flag A (Output): Active-low, open-drain output. Indicates overcurrent or thermal shutdown conditions. MIC2547 only: latched low on thermal shutdown. Ground. Both pins must be connected to GND. Current Limit Channel B: Sets current-limit threshold using an external resistor, RSET, connected to ground. 154 < RSET < 2.29k. Switch B (Output): Pins 8 and 11 must be externally connected. Input B Enable B (Input) Fault Flag B (Output) Current Limit Channel A. 4, 10 5 NC FLGA 6, 14 7 8, 11 9 12 13 15 GNDB, GNDA ILIMB OUTB INB ENB FLGB ILIMA MIC2546/2547 2 June 2000 MIC2546/2547 Micrel Absolute Maximum Ratings (Note 1) Supply Voltage (VIN) .................................................. +6.0V Output Voltage (VOUT) ............................................... +6.0V Output Current (IOUT) ............................... Internally Limited Enable Input (VEN) ................................ -0.3V to VIN +0.3V Fault Flag Voltage (VFLG) ........................................... +6.0V Fault Flag Current (IFLG) ............................................ 50mA Storage Temperature (TS) ....................... -65C to +150C Junction Temperature (TJ) ....................... Internally Limited Lead Temperature (soldering 5 sec.) ........................ 260C ESD Rating, Note 3 ...................................................... 2kV Operating Ratings (Note 2) Supply Voltage (VIN) ................................... +2.7V to +5.5V Current Limit Set Range ..................................... 0.1 to 1.5A Ambient Temperature Range (TA) ............. -40C to +85C Package Thermal Resistance SOP (JA) .......................................................... 120C/W TSSOP (JA) ..................................................... 100C/W Electrical Characteristics VIN = +5V; TA = 25C, bold indicates -40C to +85C; unless noted Symbol Parameter Supply Current Condition Switch off, OUT = open, Note 4 Switch on, OUT = open, Note 4 VEN Enable Input Voltage Enable High, Note 4 Enable Low, Note 4 Enable Input Current VEN = VOH(min) = 2.4V VEN = VOL(max) = 0.8V Enable Input Capacitance RDS(on) Switch Resistance Current Limit Factor, Note 6 Output Leakage Current tON tR tOFF tF Output Turn-On Delay Output Turn-On Rise Time Output Turnoff Delay Output Turnoff Fall Time Overtemperature Threshold Shutdown Error Flag Output Resistance Note 5 IOUT = 500mA IOUT = 100mA to 1.5A, VOUT = 1.0V to 4.0V, Note 6 Switch off RL = 10, CL = 1F, Figure 1a and 1b RL = 10, CL = 1F, Figure 1a and 1b RL = 10, CL = 1F, Figure 1a and 1b RL = 10, CL = 1F, Figure 1a and 1b TJ increasing TJ decreasing VIN = 5V, IL = 10A VIN = 3.3V, IL = 10A Error Flag Off Current EN Pulse Reset Width VIN to EN Set-Up Current-Limit Response Time Overcurrent FLG Response Time Note 1. Note 2. Note 3. Note 4. Note 5. Note 6. Min Typ 1.5 200 Max 10 320 Units A A V 2.4 1.7 1.5 .01 .01 1 80 120 276 10 5 5 0.8 1 1 V A A pF m V A ms ms s s C C A s s s s 184 230 1 1 1 2 2 22 21 140 130 4 5 0.01 15 20 1 VFLG = 5V MIC2547 Thermal Shutdown Latch MIC2547, Note 5 VOUT = 0V VOUT = VIN/2 to FLG low 5 0 25 5 Exceeding the absolute maximum rating may damage the device. The device is not guaranteed to function outside its operating rating. Devices are ESD sensitive. Handling precautions recommended. Human body model, 1.5k in series with 100pF. Off is 0.8V and on is 2.4V for the MIC2546-1 and MIC2547-1. Off is 2.4V and on is 0.8V for the MIC2546-2 and MIC2547-2. The enable input has about 200mV of hysteresis. Guaranteed by design, but not production tested. Current limit threshold is determined by: ILIMIT = 230V RSET , where RSET is in ohms. June 2000 3 MIC2546/2547 MIC2546/2547 Micrel Typical Characteristics Output On-Resistance vs. Supply Voltage 120 SUPPLY CURRENT (mA) ON-RESISTANCE (m) 100 ON-RESISTANCE (m) 90 80 Output On-Resistance vs. Temperature 280 240 200 160 120 80 40 On-State Supply Current vs. Supply Voltage 100 3.3V 80 2.7V TA = 27C TA = 27C 70 60 50 2.5 5.0V 60 3.0 3.5 4.0 4.5 5.0 SUPPLY VOLTAGE (V) 5.5 40 -40 -20 0 20 40 60 80 100 TEMPERATURE (C) 0 2.5 3.0 3.5 4.0 4.5 5.0 SUPPLY VOLTAGE (V) 5.5 On-State Supply Current vs. Temperature 280 SUPPLY CURRENT (A) SUPPLY CURRENT (A) 240 200 160 120 5.0V 80 40 2.7V 3.3V 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 Off-State Supply Current vs. Temperature 0.20 SUPPLY CURRENT (A) RL = 44 0.18 0.16 0.14 0.12 0.1 0.08 0.06 0.04 0.02 Off-State Supply Current vs. Supply Voltage TA = 27C 5.0V 3.3V 2.7V 0 -40 -20 0 20 40 60 80 100 TEMPERATURE (C) 0 -40 -20 0 20 40 60 80 100 TEMPERATURE (C) 0 2.5 3.0 3.5 4.0 4.5 5.0 SUPPLY VOLTAGE (V) 5.5 2.0 ENABLE THRESHOLD (V) 1.9 1.8 1.7 1.6 1.5 1.4 1.3 1.2 Enable Threshold Voltage vs. Supply Voltage 2.0 ENABLE THRESHOLD (V) TA = 27C VEN RISING Enable Threshold Voltage vs. Temperature 7 OUTPUT RISE TIME (ms) 6 5 4 3 Rise Time vs. Temperature 1.8 VEN RISING 1.6 1.4 1.2 1.0 -40 -20 0 20 40 60 80 100 TEMPERATURE (C) VEN FALLING 2.7V 3.3V VEN FALLING 5.0V 2 1 RL = 44 1.1 1.0 2.5 3.0 3.5 4.0 4.5 5.0 SUPPLY VOLTAGE (V) 5.5 0 -40 -20 0 20 40 60 80 100 TEMPERATURE (C) Output Fall Time vs. Temperature 2.5 OUTPUT FALL TIME (s) RL = 44 2.0 1.5 1.0 0.5 0 -40 -20 0 20 40 60 80 100 TEMPERATURE (C) 2.7V 3.3V 5.0V CURRENT LIMIT (mA) 2000 Current Limit vs. RSET OUTPUT CURRENT (mA) 2000 Output Current vs. Output Voltage RSET = 150 VIN = 5V 1500 1500 VIN = 5V 1000 RSET = 470 500 RSET = 2.3k 0 0 1 2 3 4 5 OUTPUT VOLTAGE (V) 6 1000 500 ISHORT 0 100 ISET ITH 1000 RSET () 5000 MIC2546/2547 4 June 2000 MIC2546/2547 Micrel Current Limit vs. Temperature 1100 OUTPUT CURRENT (mA) ITH 1000 900 800 700 ISHORT VIN = 5V RSET = 230 ISET CURRENT LIMIT (mA) 1000 900 800 700 600 2.5 1100 Current Limit vs. Supply Voltage ITH ISET TA = 27C RL = 230 ISHORT 600 -40 -20 0 20 40 60 80 100 TEMPERATURE (C) 3.0 3.5 4.0 4.5 5.0 SUPPLY VOLTAGE (V) 5.5 June 2000 5 MIC2546/2547 MIC2546/2547 Micrel Functional Characteristics VOUT VFLG VEN (2V/div.) (5V/div.) (10V/div.) VFLG VEN (10V/div.) (5V/div.) Turn-On Response Turnoff Response VOUT (2V/div.) VIN = 5V CIN = 4.7F CL = 1F RL = 10 IOUT (200mA/div.) VIN = 5V CIN = 4.7F CL = 1F RL = 10 MIC2546-1 TIME (500s/div.) IOUT (200mA/div.) MIC2546-1 TIME (1ms/div.) Current-Limit Response VOUT VFLG VEN (5V/div.) (10V/div.) (10V/div.) VOUT VFLG VEN (5V/div.) (10V/div.) (10V/div.) Enable Into Heavy Load Thermal Shutdown VIN = 5V CIN = 4.7F ISET = 1A RL = 1 IOUT (500mA/div.) IOUT (500mA/div.) VIN = 5V CIN = 4.7F RL = 1 ISET = 1A MIC2546-1 TIME (100ms/div.) MIC2546-1 TIME (100ms/div.) Enable Into Heavy Load VFLG VEN (5V/div.) (10V/div.) Inrush Current Response VFLG VEN (5V/div.) (10V/div.) VIN = 5V CIN = 4.7F RL = 1 ISET = 1A Reset VOUT (5V/div.) VIN = 5V CIN = 4.7F RL = 10 CL = 110F Output Latched IOUT (500mA/div.) Thermal Shutdown IOUT (1A/div.) CL = 60F CL = 10F MIC2546-1 MIC2547-1 TIME (500s/div.) TIME (500s/div.) MIC2546/2547 6 June 2000 MIC2546/2547 Micrel Test Circuit VOUT Device Under OUT Test IOUT RL CL tr VOUT 10% 90% 90% 10% tf Functional Characteristics Test Circuit Timing Diagrams 50% tOFF tON VOUT 90% 10% VEN Figure 1a. MIC2546/47-1 VEN 50% tOFF tON VOUT 90% 10% Figure 1b. MIC2546/47-2 June 2000 7 MIC2546/2547 MIC2546/2547 Micrel Output Reset EN VOUT ILIMIT IDC IOUT FLG Short-Circuit Fault Fault Removed Thermal Shutdown Reached Figure 2a. MIC2547-2 Timing: Output is reset by toggling EN EN VOUT ILIMIT IDC IOUT FLG Short-Circuit Fault Fault Removed Thermal Shutdown Reached Figure 2b. MIC2546-2 Timing MIC2546/2547 8 June 2000 MIC2546/2547 Micrel Block Diagram ENA THERMAL SHUTDOWN 1.2V REFERENCE OSC. INA CHARGE PUMP GATE CONTROL CURRENT LIMIT ILIMA RSETA RESET THERMAL SHUTDOWN LATCH (MIC2547) OUTA FLGA ENB THERMAL SHUTDOWN 1.2V REFERENCE OSC. INB CHARGE PUMP GATE CONTROL CURRENT LIMIT ILIMB RSETB RESET THERMAL SHUTDOWN LATCH (MIC2547) OUTB FLGB GNDB GNDA June 2000 9 MIC2546/2547 MIC2546/2547 Micrel Adjustable Current-Limit The short-circuit current-limit is user-adjustable with an external set resistor. Current-limit in the range of 100mA to 1.5A is available with a set point accuracy of better than 20%. The current-limit circuit prevents damage to the output MOSFET and external load. The nominal current-limit value is set with an external resistor between ILIMX and GND. For a desired current-limit, the value of the external set resistor is given by: 230V RSETX = ILIMITX Functional Description The MIC2546 and MIC2547 are dual high-side N-channel switches available with active-high or active-low enable inputs. Fault conditions turn off or inhibit turn-on of the output transistor and activate the open-drain error flag transistor making it sink current to ground. Input and Output INX is the power supply connection to the logic circuitry and the drain of the output MOSFET. OUTX is the source of the output MOSFET. In a typical circuit, current flows from INX to OUTX toward the load. If VOUT is greater than VIN, current will flow from OUTX to INX since the switch is bidirectional when enabled. The output MOSFET and driver circuitry are also designed to allow the MOSFET source to be externally forced to a higher voltage than the drain (VOUT > VIN) when the switch is disabled. In this situation, the MIC2546/47 avoids undesirable current flow from OUTX to INX. Both OUT pins for a given channel must be connected together. Thermal Shutdown Thermal shutdown shuts off the output MOSFET and signals the fault flag if the die temperature exceeds 140C. 10C of hysteresis prevents the switch from turning on until the die temperature drops to 130C. Overtemperature detection functions only when the switch is enabled. The MIC2547 features an internal latch which causes the part to remain off after thermal shutdown until a reset pulse is provided via the enable pin. While in current-limit, the thermal shutdown latch prevents on/off cycling of the output. Refer to Figure 2 for timing diagram. The flag remains low until reset. Enable Input ENX must be driven logic high or logic low, or be pulled high or low for a clearly defined input. Floating the input may cause unpredictable operation. ENX should not be allowed to go negative with respect to GND, and VENX should be less than or equal to VINX. where: 154 < RSET < 2.29k For example, to set a 1A nominal current-limit, RSET is calculated as: 230V 1A = 230 Current through RSETX increases with OUT current. The voltage across RSETX could be monitored with a high impedance comparator to provide an indication of output current. RSETX should be between 154 and 2.29k (0.5% resistor value). Short-Circuit Protection In the event of a short-circuit, the output current will fold back to approximately 80% of the short-circuit current-limit. Fault Flag FLGX is an N-channel, open-drain MOSFET output. The fault-flag is active (low) for current-limit or thermal shutdown conditions. The flag output MOSFET is capable of sinking a 10mA load to typically 100mV above ground. MIC2546/2547 10 June 2000 MIC2546/2547 Micrel PD = RDS(on) x (IOUT)2 To relate this to junction temperature, the following equation can be used: Tj = PD x JA + TA where: Tj = junction temperature TA = ambient temperature JA = is the thermal resistance of the package Transient Overcurrent Filter The inrush current from the connection of a heavy capacitive load may cause the fault flag to fall for 10s to 200s while the switch is in a constant-current mode, charging the capacitance. Adding an optional series resistor-capacitor (RSET2) in parallel with RSET, as shown in Figure 3, allows the transient current-limit to be set to a different value than steady state. A typical USB hot-plug inrush is 2A to 3A for 10s to 20s. If RSET is 435 (510mA), an RSET2 of 88 (2.5A) and CSET of 1F (RC = 100s) allows transient surge of 3A to pass for 100s without tripping the overcurrent flag (FLG). USB Power Distribution The MIC2546 is ideal for meeting USB power distribution requirements. Figure 3 depicts a USB Host application. RSET should be set to a value providing a current-limit >500mA. The accurate current-limit of the MIC2546 will reduce power supply current requirements. Also, fast reaction to short circuit faults prevent voltage droop in mobile PC applications. Printed Circuit Board Hot-Plug The MIC2546/47 are ideal inrush current-limiters suitable for hot-plug applications. Due to the integrated charge pump, the MIC2546/47 presents a high impedance when off and slowly becomes a low impedance as it turns on. This "softstart" feature effectively isolates power supplies from highly capacitive loads by reducing inrush current during hot-plug events. Applications Information Supply Filtering A 0.1F to 1F bypass capacitor from INX to GND, located near the MIC2546 and MIC2547, is strongly recommended to control supply transients. Without a bypass capacitor, an output short may cause sufficient ringing on the input (from supply lead inductance) to damage internal control circuitry. Input transients must not exceed the absolute maximum supply voltage (VIN max = 6V) even for a short duration. 4.0V to 5.5V MIC2546-1BM 1 0.1 to 1F 2 3 4 5 6 7 8 INA OUTA ENA NC FLGA OUTA ILIMA GNDA FLGB ENB 16 15 14 13 12 11 10 9 . GNDB OUTB ILIMB OUTB NC INB RSETA RSETB 0.1 to 1F Supply Bypassing Power Dissipation The device's junction temperature depends on several factors such as the load, PCB layout, ambient temperature and package type. Equations that can be used to calculate power dissipation and junction temperature are found below. Calculation of power dissipation can be accomplished by the following equation: (+) (-) 5V 4.7F 1.5k 2% MIC5203-3.3 LDO Regulator 10k 10k 100k 3.3V USB Controller V+ ON/OFF MIC2546-2BM INA ENA NC FLGA D+ D- GND OUTA GNDA FLGB ENB NC INB 120F VBUS D+ 0.01F D- GND Ferrite Bead Downstream USB Port 2 4.75V min. 500mA max. Ferrite Bead VBUS OUTA ILIMA 100k VBUS D+ D- GND IN OUT GND RSET 0.01F 120F D+ D- GND OVERCURRENT Downstream USB Port 1 4.75V min. 500mA max. RSET GNDB OUTB ILIMB OUTB Bold lines indicate 0.1" wide, 1-oz. copper high-current traces. RSET(2) CSET (optional) Figure 3. USB Host Application June 2000 11 MIC2546/2547 MIC2546/2547 Micrel Package Information PIN 1 0.157 (3.99) 0.150 (3.81) DIMENSIONS: INCHES (MM) 0.020 (0.51) REF 0.050 (1.27) BSC 0.020 (0.51) 0.013 (0.33) 0.0098 (0.249) 0.0040 (0.102) 45 0-8 0.050 (1.27) 0.016 (0.40) 0.244 (6.20) 0.228 (5.79) 0.0648 (1.646) 0.0434 (1.102) 0.394 (10.00) 0.386 (9.80) SEATING PLANE 16-Pin SOP (M) 4.50 (0.177) 6.4 BSC (0.252) 4.30 (0.169) DIMENSIONS: MM (INCH) 0.30 (0.012) 0.19 (0.007) 7.90 (0.311) 7.70 (0.303) 1.10 MAX (0.043) 0.20 (0.008) 0.09 (0.003) 0.65 BSC (0.026) 0.15 (0.006) 0.05 (0.002) 8 0 1.00 (0.039) REF 0.70 (0.028) 0.50 (0.020) 16-Pin TSSOP (TS) MICREL INC. 1849 FORTUNE DRIVE SAN JOSE, CA 95131 TEL USA + 1 (408) 944-0800 FAX + 1 (408) 944-0970 WEB http://www.micrel.com This information is believed to be accurate and reliable, however no responsibility is assumed by Micrel for its use nor for any infringement of patents or other rights of third parties resulting from its use. No license is granted by implication or otherwise under any patent or patent right of Micrel Inc. (c) 2000 Micrel Incorporated MIC2546/2547 12 June 2000 |
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