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19-1225; Rev 2; 1/98
High-Voltage, Low-Power Linear Regulators for Notebook Computers
________________General Description
The MAX1615/MAX1616 are micropower, SOT23-5 linear regulators that supply always-on, keep-alive power to CMOS RAM and microcontrollers (Cs) in systems with high-voltage batteries. Key features include wide input voltage range, low dropout voltage, and low quiescent supply current. Despite a miserly 8A (max) no-load supply current, the MAX1615/MAX1616 have excellent line-transient response and AC power-supply rejection ratio. They provide a clean, fixed 5V or 3.3V output (MAX1615) or an adjustable 1.24V to 28V output (MAX1616), even when subjected to fast supply-voltage changes that occur during the switchover from battery to AC adapter input power. The space-saving SOT23-5 package has excellent thermal characteristics and tolerates up to 571mW of power dissipation. Fault protection is provided by internal foldback current limiting and thermalshutdown circuitry.
____________________________Features
o 4V to 28V Input Range o 8A (max) Quiescent Supply Current o <1A Shutdown Supply Current o 3.3V or 5V, Pin-Selectable Output (MAX1615) Adjustable 1.24V to 28V Output (MAX1616) o 30mA Output Current o 2% Initial Output Accuracy o Thermal-Overload Protection o 5-Pin SOT23 Package o Low Cost
MAX1615/MAX1616
________________________Applications
CMOS/RTC Backup Power Microcontroller Power Notebook Computers Smart-Battery Packs PDAs and Handy-Terminals Battery-Powered Systems
_______________Ordering Information
PART TEMP. RANGE PINSOT PACKAGE TOP MARK 5 SOT23-5 5 SOT23-5 ABZD ABZE
MAX1615EUK-T -40C to +85C MAX1616EUK-T -40C to +85C
____________Typical Operating Circuit
___________________Pin Configuration
TOP VIEW
IN OUT OUTPUT VOLTAGE IN 1 COUT 4.7F 5/3 OUT 3 4 5/3 (FB) 5 SHDN
MAX1615
BATTERY CIN 0.1F SHDN GND
GND 2
MAX1615 MAX1616
SOT23-5
( ) ARE FOR MAX1616.
________________________________________________________________ Maxim Integrated Products
1
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High-Voltage, Low-Power Linear Regulators for Notebook Computers MAX1615/MAX1616
ABSOLUTE MAXIMUM RATINGS
IN to GND .................................................................-0.3V to 30V Terminal Voltages to GND SHDN to GND ...........................................-0.3V to (VIN + 0.3V) 5/3 to GND ............................................-0.3V to (VOUT + 0.3V) FB (MAX1616) to GND .........................-0.3V to (VOUT + 0.3V) OUT to GND...........................................................-0.3V to 30V OUT Short-Circuit to GND ...............................................30sec Note 1: See Operating Region and Power Dissipation section.
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.
Continuous OUT Current.....................................................40mA Continuous Power Dissipation (TA = +70C) (Note 1) SOT23-5 (derate 7.1mW/C above +70C)...................571mW Operating Temperature Range MAX161_EUK-T ...............................................-40C to +85C Storage Temperature Range .............................-65C to +160C Lead Temperature (soldering, 10sec) .............................+300C
ELECTRICAL CHARACTERISTICS
(VIN = 15V, SHDN = VIN, ILOAD = 5A, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25C.) (Note 2) PARAMETER Input Voltage Range Supply Current Minimum Load Current Shutdown Supply Current Dropout Supply Current IIN SHDN = GND (shutdown mode) Output set to 5V, VIN = 4V ILOAD = 1mA, TA = +25C, VIN = 6V to 28V ILOAD = 5A to 30mA, TA = TMIN to TMAX, VIN = 6V to 28V FB = OUT, VIN = 6V to 28V VFB = 1.3V ILOAD = 30mA (Note 4) VIN = 6V IN = unconnected, VOUT forced to 5V MAX1615 MAX1616 Rising edge of IN or SHDN to OUT within specification limits, RL = 500, COUT = 6.8F, VOUT set to 5V VOSH RL = 500, COUT = 10F within 90% of nominal output voltage 0.5 0.16 0.23 1 100 70 TA = +25C TMIN = TMIN to TMAX TA = +25C 5/3 = GND 5/3 = OUT 5/3 = GND 5/3 = OUT TA = +25C, ILOAD = 1mA TA = TMIN to TMAX, ILOAD = 5A to 30mA 3.26 4.95 3.15 4.75 1.215 1.18 -10 12 1.240 70 3.33 5.05 3.40 5.15 V 3.48 5.25 1.265 1.28 30 350 V V nA mV mA A F/mA SYMBOL VIN IIN SHDN = IN, TA = +25C SHDN = IN, VIN = 6V to 28V, TA = TMIN to TMAX CONDITIONS MIN 4 6.2 TYP MAX 28 8 15 5 1.5 3 UNITS V A A A A
Output Voltage (MAX1615) (Note 3)
FB Threshold (MAX1616) (Note 3) FB Input Current (MAX1616) Dropout Voltage Output Current Limit OUT Reverse Leakage Current Capacitive Load Requirements (Note 5) Start-Up Time Response
VFBT
IFB VDO
ms
Start-Up Overshoot
%VOUT
2
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High-Voltage, Low-Power Linear Regulators for Notebook Computers MAX1615/MAX1616
ELECTRICAL CHARACTERISTICS (continued)
(VIN = 15V, SHDN = VIN, ILOAD = 5A, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25C.) (Note 2) PARAMETER SHDN Input Threshold Voltage SHDN Input Current Thermal-Shutdown Temperature TSHDN SYMBOL VIL VIH V SHDN = 0V or 15V V SHDN = 0V or 15V, hysteresis = +20C 1.4 -1 150 1 CONDITIONS MIN TYP MAX 0.25 UNITS V A C
Note 2: Limits are 100% production tested at TA = +25C. Limits over the operating temperature range are guaranteed through correlation using standard quality-control (SQC) methods. Note 3: Pulse tested at VIN = 28V, ILOAD = 30mA to avoid exceeding package power-dissipation limits. Note 4: Guaranteed by design. Tested with VOUT set to 5V. Dropout voltage is tested by reducing the input voltage until VOUT drops to 100mV below its nominal value, measured with VIN starting 2V above VOUT. Note 5: Use at least 1F minimum for light loads. Add 0.125F/mA (0.2F/mA for the MAX1616) for loads greater than 100A, not production tested. See Capacitor Selection in the Applications Information section.
__________________________________________Typical Operating Characteristics
(VOUT set to 5V, TA = +25C, unless otherwise noted.)
SAFE LOAD-CURRENT OPERATING AREA vs. SUPPLY VOLTAGE
MAX1615-01
GROUND CURRENT vs. SUPPLY VOLTAGE AT VARIOUS LOADS
MAX1615-02
SUPPLY CURRENT vs. SUPPLY VOLTAGE
8.5 SUPPLY CURRENT (A) 8.0 7.5 7.0 6.5 6.0 5.5 5.0 5 10 TA = +85C TA = +25C TA = -40C 15 20 25 30
MAX1615-03
60 VOUT = 5V 50 OUTPUT CURRENT (mA) 40 30 20 10 0 0 5 10 15 20 25 POWERDISSIPATION LIMIT REGION
8 7 GROUND CURRENT (mA) 6 5 4 3 2 1 0 15mA 5 10 15 20 25 45mA 35mA 25mA 5mA 65mA 55mA
9.0
30
30
SUPPLY VOLTAGE (V)
SUPPLY VOLTAGE (V)
SUPPLY VOLTAGE (V)
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High-Voltage, Low-Power Linear Regulators for Notebook Computers MAX1615/MAX1616
____________________________Typical Operating Characteristics (continued)
(VOUT set to 5V, TA = +25C, unless otherwise noted.)
SHUTDOWN SUPPLY CURRENT vs. SUPPLY VOLTAGE
MAX1615-04
RIPPLE REJECTION vs. FREQUENCY
MAX1615-05
1.6 SHUTDOWN SUPPLY CURRENT (A) 1.4 1.2 1.0 0.8 0.6 0.4 0.2 0 4 8 12 16 20 24
-70 -60 RIPPLE REJECTION (dB) -50 -40 -30 -20 -10 ILOAD = 10mA 0
28
0.01
0.1
1 FREQUENCY (kHz)
10
100
SUPPLY VOLTAGE (V)
TIME TO EXIT SHUTDOWN
MAX1615-06
LINE-TRANSIENT RESPONSE
MAX1615-07
LOAD-TRANSIENT RESPONSE
MAX1615-08
+5V SHDN 0V
+20V CIN 10F VIN +10V VOUT 50mV/div COUT 4.7F VOUT 50mV/div
+5V OUT 0V VIN = 10V 500s/div 50s/div 100s/div
IOUT 30mA/div
DROPOUT SUPPLY CURRENT vs. SUPPLY VOLTAGE
80 70 VIN - VOUT (V) 60 50 40 30 20 10 0 4.0 4.2 4.4 4.6 4.8 5.0 5.2 5.4 5.6 5.8 6.0 SUPPLY VOLTAGE (V) 0 0 5 TA = -40C TA = +25C TA = 0C 0.20 0.15 0.10 0.05 TA = +85C
MAX1615-09
DROPOUT VOLTAGE vs. LOAD CURRENT
MAX1615-10
90 DROPOUT SUPPLY CURRENT (A)
0.30 0.25
10
15
20
25
30
35
40
LOAD CURRENT (mA)
4
_______________________________________________________________________________________
High-Voltage, Low-Power Linear Regulators for Notebook Computers
______________________________________________________________Pin Description
PIN MAX1615 1 2 3 4 -- 5 MAX1616 1 2 3 -- 4 5 NAME IN GND OUT 5/3 FB SHDN FUNCTION Positive Input Voltage. Connect to a +4V to +28V supply. Ground Regulator Output Preset Output Voltage Select. Connect to GND for 3.3V output or to OUT for 5.0V output. Feedback Input. Regulates to 1.24V nominally. Shutdown, active low input. Connect to IN for automatic start up.
MAX1615/MAX1616
IN VREF
OUT CURRENT LIMIT SHDN
The MAX1615's output voltage is fed back through an internal resistor voltage divider connected to OUT. Set the output voltage to either 3.3V or 5.0V with the 5/3 pin. Select the 5V output by connecting 5/3 to OUT, or the 3.3V output by connecting 5/3 to GND. The MAX1616 uses external feedback, allowing the output voltage to be set by external resistors (see Setting the MAX1616 Output Voltage section). The typical FB threshold is at 1.24V.
MAX1615 MAX1616
Shutdown
The device enters shutdown mode when SHDN is low. In shutdown mode, the pass transistor, control circuit, reference, and all biases turn off, reducing the supply current to below 1A. Connect SHDN to IN for automatic start-up.
Current Limit
Output current is limited to 100mA (typical). The current limit exceeds the 30mA (max) safe operating limit. The output can be shorted to ground for 30 seconds without damaging the part.
FB (MAX1616)
5/3 (MAX1615)
GND
Thermal-Overload Protection
When the junction temperature exceeds TJ = +150C, the thermal sensor sends a signal to the shutdown logic, turning off the pass transistor and allowing the IC to cool. The thermal sensor turns the pass transistor on again after the IC's junction temperature cools by +20C (typical), resulting in a pulsating output during continuous thermal-overload conditions.
Figure 1. Functional Diagram
_______________Detailed Description
The MAX1615/MAX1616 low-quiescent-current linear regulators are designed primarily for high input voltage applications. The MAX1615 supplies a preselected 3.3V or 5.0V output for loads up to 30mA. The MAX1616 provides an adjustable voltage from 1.24V to 28V. The maximum output current is a function of the package's maximum power dissipation for a given temperature. A 5A load is required to maintain output regulation.
Operating Region and Power Dissipation
Maximum power dissipation depends on the thermal resistance of the case and circuit board, the temperature difference between the die junction and ambient air, and the rate of air flow. The device's power dissipa5
_______________________________________________________________________________________
High-Voltage, Low-Power Linear Regulators for Notebook Computers MAX1615/MAX1616
tion is P = IOUT (VIN - VOUT). The power dissipation at +70C ambient is 571mW (see Absolute Maximum Ratings). The thermal resistance junction-to-case of the SOT23-5 package is 81C/W, and the maximum safe junction temperature is +150C. The GND pin performs the dual function of providing an electrical connection to ground and channeling heat away. Connect GND to ground using a large pad or ground plane.
6V TO 28V 0.1F SHDN GND R2 IN OUT OUTPUT VOLTAGE
MAX1616
FB
R1 6.8F*
__________Applications Information
Setting the MAX1616 Output Voltage
Set the MAX1616's output voltage with two resistors, R1 and R2 (Figure 2). Choose R2 = 250k to maintain a 5A minimum load and calculate R1 using the following equation: V R1 = R2 OUT - 1 VFBT where VFBT = 1.24V (typical).
*15F for VOUT <3.3V
Figure 2. MAX1616 Typical Application Circuit
Table 1. Surface-Mount Capacitor Manufacturers
TYPE MANUFACTURER AVX Electrolytic Matsuo Sprague AVX Ceramic Matsuo X7R CAPACITOR TPS series 267 series 593D, 595 series X7R
Capacitor Selection
Use a 0.1F minimum capacitor on the input. Higher values will improve line-transient response. Use 1F minimum on the output, or 4.7F for the full 30mA load current (6.8F, MAX1616). Otherwise, use 1F plus 0.125F/mA (0.2F/A, MAX1616). For output voltages less than 3.3V, use 15F instead of 6.8F. The output capacitor's effective series resistance (ESR) must be less than 1 for stable operation.
Output Voltage Noise
The MAX1615/MAX1616 typically exhibit 5mVp-p of noise during normal operation. This is negligible in most applications. In applications that include analogto-digital converters (ADCs) of more than 12 bits, consider the ADC's power-supply-rejection specifications.
Table 2. Component Suppliers
SUPPLIER AVX Matsuo Sprague PHONE (803) 946-0690 (714) 969-2491 (603) 224-1961 FAX (803) 626-3123 (714) 960-6492 (603) 224-1430
Transient Response
The Typical Operating Characteristics show the MAX1615/MAX1616's load-transient response. Two of the output response's components can be observed on the load-transient graph: a DC shift from the output impedance due to the different load currents, and the transient response. Typical step changes in the load current from 10mA to 20mA produce 50mV transients. Increasing the output capacitor's value attenuates transient spikes.
___________________Chip Information
TRANSISTOR COUNT: 386
6
_______________________________________________________________________________________
High-Voltage, Low-Power Linear Regulators for Notebook Computers
__________________________________________________Tape-and-Reel Information
E D P0 P2 W B0
MAX1615/MAX1616
F
D1
t
NOTE: DIMENSIONS ARE IN MM. AND FOLLOW EIA481-1 STANDARD.
P A0
K0
A0 B0 D D1
3.200 3.099 1.499 0.991
0.102 0.102 +0.102 +0.000 +0.254 +0.000
E F K0 P
1.753 3.505 1.397 3.988
0.102 0.051 0.102 0.102
P0 P010 P2 t W
3.988 40.005 2.007 0.254 8.001
0.102 0.203 0.051 0.127 +0.305 -0.102
5 SOT23-5
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High-Voltage, Low-Power Linear Regulators for Notebook Computers MAX1615/MAX1616
________________________________________________________Package Information
SOT5L.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.
8 _____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 (c) 1998 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.

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