MAX1792 500mA Low-Dropout Linear Regulator in µMAX General Description Features The MAX1792 low-dropout linear regulator operates from a +2.5V to +5.5V supply and delivers a guaranteed 500mA load current with low 130mV dropout. The high-accuracy (±1%) output voltage is preset at an internally trimmed voltage (see Selector Guide) or can be adjusted from 1.25V to 5.0V with an external resistive divider. An internal PMOS pass transistor allows the low 80µA supply current to remain independent of load, making this device ideal for portable battery-operated equipment such as personal digital assistants (PDAs), cellular phones, cordless phones, base stations, and notebook computers. Other features include an active-low open-drain reset output with a 4ms timeout period that indicates when the output is out of regulation, a 0.1µA shutdown mode, short-circuit protection, and thermal shutdown protection. The device is available in a miniature 1.3W, 8-pin power-µMAX package with a metal pad on the underside of the package. o Guaranteed 500mA Output Current o Low 130mV Dropout at 500mA o Up to ±1% Output Voltage Accuracy ________________________Applications *Insert the desired two-digit suffix (see Selector Guide) into the blanks to complete the part number. +Denotes a lead(Pb)-free/RoHS-compliant package. /V denotes an automotive qualified part. Contact factory for other preset output voltages. Notebook Computers Cellular and Cordless Telephones Preset at 1.5V, 1.8V, 2.5V, 3.3V, or 5.0V Adjustable from 1.25V to 5.0V o Reset Output with 4ms Timeout Period o Low 80µA Ground Current o 0.1µA Shutdown Current o Thermal Overload Protection o Output Current Limit o Tiny 1.3W Power-µMAX Package Ordering Information PART* TEMP RANGE PIN-PACKAGE MAX1792EUA_ _+ -40°C to +85°C 8 Power-μMAX MAX1792EUA_ _/V+ -40°C to +85°C 8 Power-μMAX Personal Digital Assistants (PDAs) Selector Guide Palmtop Computers PART AND SUFFIX Base Stations V OUT μMAX TOP MARK USB Hubs MAX1792EUA15+ 1.5V or Adj. AAAE Docking Stations MAX1792EUA18+ 1.8V or Adj. AAAA MAX1792EUA25+ 2.5V or Adj. AAAB MAX1792EUA33+ 3.3V or Adj. AAAC MAX1792EUA50+ 5.0V or Adj. AAAD MAX1792EUA33/V+ 3.3V or Adj. AACP Typical Operating Circuit VIN = +2.5V TO +5.5V CIN 1µF IN NC OUT IN OUT Pin Configuration VOUT COUT 3.3µF TOP VIEW + MAX1792 ON SHDN IN 1 RRST 100k RST OFF IN 2 TO µC RST 3 SHDN 4 SET MAX1792 EP 8 OUT 7 OUT 6 SET 5 GND GND POWER-µMAX For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxim’s website at www.maximintegrated.com. 19-1699; Rev 2; 11/11 MAX1792 500mA Low-Dropout Linear Regulator in µMAX ABSOLUTE MAXIMUM RATINGS IN, SHDN, RST, SET to GND ....................................-0.3V to +6V OUT to GND ................................................-0.3V to (VIN + 0.3V) Output Short-Circuit Duration ........................................Indefinite Continuous Power Dissipation (TA = +70°C) 8-Pin Power-µMAX (derate 17mW/°C above +70°C) .......1.3W Operating Temperature Range ...........................-40°C to +85°C Junction Temperature ......................................................+150°C Storage Temperature Range .............................-65°C to +150°C Lead Temperature (soldering, 10s) .................................+300°C Soldering Temperature (reflow) .......................................+260°C 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 (VIN = VOUT(NOM) + 500mV, or VIN = +2.5V (whichever is greater), SHDN = IN, TA = 0°C to +85°C, unless otherwise noted. Typical values are at TA = +25°C.) PARAMETER Input Voltage Input Undervoltage Lockout SYMBOL CONDITIONS VIN VUVLO VOUT Rising, 75mV hysteresis 2.0 +1 +1.5 IOUT = 100mA, TA = 0°C to +85°C -2 +2 IOUT = 1mA to 500mA, VIN > VOUT + 0.5V, TA = 0°C to +85°C -3 +3 1.25 5 VIN = +2.7V, VOUT set to 2.0V, IOUT = 100mA TA = +85°C 1.229 TA = 0°C to +85°C 1.219 IOUT VIN 2.7V 500 Short-Circuit Current Limit ILIM VOUT = 0V, VIN 2.7V 0.55 SET Dual Mode™ Threshold IOUT = 1mA mARMS 0.8 100 80 IOUT = 500mA 1.8 A A 150 mV +100 nA 250 110 μA VOUT = 5.0V 120 225 VOUT = 3.3V 130 250 VOUT = 2.5V 210 360 0 +0.15 %/V IOUT = 1mA to 500mA 0.4 1.0 % 10Hz to 1MHz, C OUT = 3.3μF (ESR < 0.1) 115 SHDN = GND, VIN = 5.5V 0.1 IOUT = 500mA Line Regulation VLNR VIN from (VOUT + 100mV) to 5.5V, ILOAD = 5mA Load Regulation VLDR Output Voltage Noise V 1.281 -100 VIN VOUT Dropout Voltage (Note 1) % 1.271 1.6 50 VSET = 1.25V 1.250 % V VOUT > 96% of nominal value, VIN 2.7V IQ V -1 Maximum Output Current Ground-Pin Current V 2.3 -1.5 VSET ISET UNITS 5.5 Preset VOUT 2.5V SET Voltage Threshold (Adjustable Mode) SET Input Bias Current 2.15 MAX Preset VOUT < 2.5V Adjustable Output Voltage Range In-Regulation Current Limit TYP 2.5 IOUT = 100mA, TA = +85°C Output Voltage Accuracy (Preset Mode) MIN -0.15 mV μVRMS SHUTDOWN Shutdown Supply Current SHDN Input Threshold SHDN Input Bias Current IOFF VIH 2.5V < VIN < 5.5V VIL 2.5V < VIN < 5.5V SHDN = IN or GND 15 1.6 0.6 10 100 μA V nA Dual Mode is a trademark of Maxim Integrated Products. 2 Maxim Integrated MAX1792 500mA Low-Dropout Linear Regulator in µMAX ELECTRICAL CHARACTERISTICS (continued) (VIN = VOUT(NOM) + 500mV, or VIN = +2.5V (whichever is greater), SHDN = IN, TA = 0°C to +85°C, unless otherwise noted. Typical values are at TA = +25°C.) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS 0.01 0.1 V 5.5 V 100 nA RESET OUTPUT Reset Output Low Voltage VOL RST sinking 1mA Operating Voltage Range for Valid Reset RST sinking 100μA RST Output High Leakage Current VRST = +5.5V RST Threshold RST Release Delay tRP 1.0 Rising edge, referred to VOUT(NOMINAL) 90 93 96 % Rising edge of OUT to rising edge of RST 1.5 4.5 8 ms THERMAL PROTECTION Thermal Shutdown Temperature TSHDN 170 °C Thermal Shutdown Hysteresis TSHDN 20 °C ELECTRICAL CHARACTERISTICS (VIN = VOUT(NOM) + 500mV, or VIN = +2.5V (whichever is greater), SHDN = IN, TA = -40°C to +85°C, unless otherwise noted.) (Note 2) PARAMETER Input Voltage SYMBOL CONDITIONS MIN MAX 2.5 5.5 V Rising or falling 2.0 2.3 V IOUT = 100mA -2 +2 IOUT = 1mA to 500mA -3 +3 1.25 5 V 1.212 1.288 V VIN Input Undervoltage Lockout VUVLO Output Voltage Accuracy (Preset Mode) VOUT Adjustable Output Voltage Range SET Voltage Threshold (Adjustable Mode) VSET Maximum Output Current IOUT Short-Circuit Current Limit ILIM IOUT = 100mA 500 VOUT = 0V SET Dual Mode Threshold SET Input Bias Current Ground-Pin Current ISET VSET = 1.25V IQ IOUT = 1mA 0.55 1.8 A 50 150 mV -100 +100 nA 250 μA 225 VOUT = 3.3V 250 VOUT = 2.5V 360 IOUT = 500mA Line Regulation VLNR VIN from (VOUT + 100mV) to 5.5V, ILOAD = 5mA Load Regulation VLDR % mARMS VOUT = 5.0V VIN VOUT Dropout Voltage (Note 1) UNITS -0.15 mV +0.15 %/V IOUT = 1mA to 500mA 1.0 % 15 μA SHUTDOWN Shutdown Supply Current IOFF SHDN = GND, VIN = +5.5V SHDN Input Threshold VIH 2.5V < VIN < 5.5V VIL 2.5V < VIN < 5.5V 0.6 SHDN = IN or GND 100 SHDN Input Bias Current Maxim Integrated I SHDN 1.6 V nA 3 MAX1792 500mA Low-Dropout Linear Regulator in µMAX ELECTRICAL CHARACTERISTICS (continued) (VIN = VOUT(NOM) + 500mV, or VIN = +2.5V (whichever is greater), SHDN = IN, TA = -40°C to +85°C, unless otherwise noted.) (Note 2) PARAMETER SYMBOL CONDITIONS MIN MAX UNITS 0.1 V 5.5 V 100 nA RESET OUTPUT Reset Output Low Voltage RST sinking 1mA VOL Operating Voltage Range for Valid Reset RST sinking 100μA RST Output High Leakage Current V RST = +5.5V RST Threshold RST Release Delay tRP 1.0 Rising edge, referred to VOUT(NOMINAL) 90 96 % Rising edge of OUT to rising edge of RST 1.5 8 ms Note 1: Dropout voltage is defined as VIN - VOUT, when VOUT is 100mV below the value of VOUT measured when VIN = VOUT(NOM) + 0.5V. Since the minimum input voltage is 2.5V, this specification is only meaningful when VOUT(NOM) ≥ 2.5V. For VOUT(NOM) between 2.5V and 3.5V, use the following equations: Typical Dropout = -93mV/V VOUT(NOM) + 445mV; Guaranteed Maximum Dropout = -137mV/V VOUT(NOM) + 704mV. For VOUT(NOM) ≥ 3.5V: Typical Dropout = 120mV; Guaranteed Maximum Dropout = 225mV. Note 2: Specifications to -40°C are guaranteed by design, not production tested. Typical Operating Characteristics (MAX1792EUA33, VIN = VOUT + 500mV, SHDN = IN, CIN = 1µF, COUT = 3.3µF, TA = +25°C, unless otherwise noted.) OUTPUT VOLTAGE OUTPUT VOLTAGE OUTPUT VOLTAGE vs. INPUT VOLTAGE vs. TEMPERATURE vs. LOAD CURRENT 1.5 1.0 3.29 0 3.0 3.5 4.0 4.5 5.0 5.5 3.29 -40 100 200 300 400 500 600 700 800 -15 10 35 60 INPUT VOLTAGE (V) LOAD CURRENT (mA) TEMPERATURE (°C) DROPOUT VOLTAGE vs. LOAD CURRENT GROUND-PIN CURRENT vs. INPUT VOLTAGE GROUND-PIN CURRENT vs. LOAD CURRENT 200 TA = +25°C 100 TA = -40°C IOUT = 500mA 120 100 80 140 IOUT = 0A 60 40 130 GROUND-PIN CURRENT (μA) TA = +85°C 140 GROUND-PIN CURRENT (μA) 250 150 3.30 3.27 0 MAX1792-04 2.5 3.31 3.28 3.27 2.0 MAX1792-03 MAX1792-02 3.30 3.28 0.5 DROPOUT VOLTAGE (mV) 3.31 VIN = 5.5V 85 MAX1792-06 2.0 VIN = VOUT + 500mV IOUT = 0A 3.32 OUTPUT VOLTAGE (V) IOUT = 500mA 3.33 MAX1792-05 OUTPUT VOLTAGE (V) 2.5 3.32 OUTPUT VOLTAGE (V) IOUT = 0A 3.0 3.33 MAX1792-01 3.5 120 110 VIN = 3.8V 100 90 80 50 20 0 0 0 100 200 300 400 500 600 700 800 LOAD CURRENT (mA) 4 70 60 0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 INPUT VOLTAGE (V) 0 100 200 300 400 500 600 700 800 LOAD CURRENT (mA) Maxim Integrated MAX1792 500mA Low-Dropout Linear Regulator in µMAX Typical Operating Characteristics (continued) (MAX1792EUA33, VIN = VOUT + 500mV, SHDN = IN, CIN = 1µF, COUT = 3.3µF, TA = +25°C, unless otherwise noted.) GROUND-PIN CURRENT vs. TEMPERATURE PSRR (dB) 80 75 -50 -40 -30 70 -20 -10 60 0 -15 10 35 60 85 0.01 0.1 1 10 100 TEMPERATURE (°C) FREQUENCY (kHz) OUTPUT SPECTRAL NOISE DENSITY vs. FREQUENCY OUTPUT NOISE DC TO 1MHz 10 COUT = 3.3μF IOUT = 50mA 1000 MAX1792-09 -40 MAX1792-10 GROUND-PIN CURRENT (μA) -60 85 65 OUTPUT SPECTRAL NOISE DENSITY (μV/√Hz) COUT = 3.3μF IOUT = 50mA -70 MAX1792-08 VIN = VOUT + 500 mV IOUT = 0A 90 -80 MAX1792-07 95 POWER-SUPPLY REJECTION RATIO vs. FREQUENCY 1 VOUT 200μV/div 0.1 0.01 VOUT = 3.3V ROUT = 66Ω (50mA) 0.001 0.1 1 10 100 1000 20ms/div FREQUENCY (kHz) REGION OF STABLE COUT ESR vs. LOAD CURRENT LOAD-TRANSIENT RESPONSE MAX1792-12 MAX1792-11 100 IOUT 500mA/div COUT ESR (Ω) 10 COUT = 3.3μF 1 VOUT 20mV/div COUT = 10μF STABLE REGION 0.1 VIN = VOUT + 500mV CIN = 10μF ROUT = 660Ω TO 6.6Ω (5mA TO 500mA) 0.01 0 100 200 300 400 500 600 700 800 10μs/div LOAD CURRENT (mA) Maxim Integrated 5 MAX1792 500mA Low-Dropout Linear Regulator in µMAX Typical Operating Characteristics (continued) (MAX1792EUA33, VIN = VOUT + 500mV, SHDN = IN, CIN = 1µF, COUT = 3.3µF, TA = +25°C, unless otherwise noted.) LOAD-TRANSIENT RESPONSE NEAR DROPOUT LINE-TRANSIENT RESPONSE MAX1792-13 MAX1792-14 6V IOUT 500mA/div VIN 1V/div 3V VOUT 50mV/div VOUT 10mV/div VIN = VOUT + 100mV CIN = 10μF ROUT = 660Ω TO 6.6Ω (5mA TO 500mA) 20μs/div 100μs/div RST WAVEFORM SHUTDOWN WAVEFORM MAX1792-16 MAX1792-15 2V 5V VSHDN 1V/div 0V VIN 2.5V/div 0V VOUT 2V/div 3V VOUT 1V/div 0V VRST 2V/div 0V 0V ROUT = 6.6Ω (500mA) ROUT = 66Ω (50mA) 20ms/div 20μs/div Pin Description 6 PIN NAME FUNCTION 1, 2 IN Regulator Input. Supply voltage can range from +2.5V to +5.5V. Bypass with a 1µF capacitor to GND (see Capacitor Selection and Regulator Stability). Connect both input pins together externally. 3 RST Open-Drain Active-Low Reset Output. RST remains low while the output voltage (VOUT) is below the reset threshold and for at least 4ms after VOUT rises above the reset threshold. Connect a 100kΩ pullup resistor to OUT to obtain an output voltage. 4 SHDN Active-Low Shutdown Input. A logic low reduces supply current to 0.1µA. In shutdown, the RST output is low and OUT is pulled low through an internal 5kΩ resistor. Connect to IN for normal operation. 5 GND Ground. This pin and the exposed pad also function as a heatsink. Solder both to a large pad or to the circuit-board ground plane to maximize power dissipation. 6 SET Voltage-Setting Input. Connect to GND for preset output. Connect to a resistive divider between OUT and GND to set the output voltage between 1.25V and 5.0V. 7, 8 OUT Regulator Output. Sources up to 500mA. Bypass with a 3.3µF low-ESR capacitor to GND. Use a 4.7µF capacitor for output voltages below 2V. Connect both output pins together externally. — EP Exposed Pad. Solder to ground plane to maximize thermal performance. Not internally connected to ground. Maxim Integrated MAX1792 500mA Low-Dropout Linear Regulator in µMAX VIN = +2.5V TO +5.5V IN CIN 1µF IN THERMAL SENSOR MOSFET DRIVER WITH I LIM OUT ON VOUT = 1.25V TO 5.0V SHDN COUT 3.3µF OUT OFF SHUTDOWN LOGIC 5k VREF 1.25V ERROR AMPLIFIER LOGIC SUPPLY VOLTAGE (VOUT) RRST 100k R1 MAX1792 RST TO µC SET DELAY TIMER R2 93% VREF 100mV GND Figure 1. Functional Diagram Detailed Description The MAX1792 is a low-dropout, low-quiescent-current linear regulator designed primarily for battery-powered applications. The device supplies loads up to 500mA and is available with preset output voltages. As illustrated in Figure 1, the MAX1792 consists of a 1.25V reference, error amplifier, P-channel pass transistor, and internal feedback voltage-divider. The 1.25V reference is connected to the error amplifier, which compares this reference with the feedback voltage and amplifies the difference. If the feedback voltage is lower than the reference voltage, the pass-transistor gate is pulled lower, which allows more current to pass to the output and increases the output voltage. If the feedback voltage is too high, the passtransistor gate is pulled up, allowing less current to pass to the output. Maxim Integrated The output voltage is fed back through either an internal resistive divider connected to OUT or an external resistor network connected to SET. The Dual Mode comparator examines VSET and selects the feedback path. If VSET is below 50mV, the internal feedback path is used and the output is regulated to the factory-preset voltage. Additional blocks include an output current limiter, thermal sensor, and shutdown logic. Internal P-Channel Pass Transistor The MAX1792 features a 0.25Ω P-channel MOSFET pass transistor. Unlike similar designs using PNP pass transistors, P-channel MOSFETs require no base drive, which reduces quiescent current. PNP-based regulators also waste considerable current in dropout when the pass transistor saturates, and use high base-drive currents under large loads. 7 MAX1792 500mA Low-Dropout Linear Regulator in µMAX Reset Output R1 = R2 IN OUT IN OUT VOUT 1.25V V IN = +2.5V TO +5.5V -1 VOUT CIN 1µF COUT 3.3µF MAX1792 R1 ON SHDN SET Current Limit OFF R2 RST GND Figure 2. Adjustable Output Using External Feedback Resistors The MAX1792 does not suffer from these problems and consumes only 110µA of quiescent current under heavy loads as well as in dropout. Output Voltage Selection The MAX1792’s Dual Mode operation allows operation in either a preset voltage mode or an adjustable mode. Connect SET to GND to select the preset output voltage. The two-digit part number suffix identifies the output voltage (see Selector Guide ). For example, the MAX1792EUA33 has a preset 3.3V output voltage. The output voltage may also be adjusted by connecting a voltage-divider from OUT to SET to GND (Figure 2). Select R2 in the 25kΩ to 100kΩ range. Calculate R1 with the following equation: R1 = R2 [(VOUT / VSET) - 1] where VSET = 1.25V and VOUT may range from 1.25V to 5.0V. Shutdown Pull SHDN low to enter shutdown. During shutdown, the output is disconnected from the input and supply current drops to 0.1µA. When in shutdown, RST pulls low and OUT is discharged through an internal 5kΩ resistor. The capacitance and load at OUT determine the rate at which VOUT decays. SHDN can be pulled as high as +6V, regardless of the input and output voltage. 8 The reset output (RST) pulls low when OUT is less than 93% of the nominal regulation voltage. Once OUT exceeds 93% of the nominal voltage, RST goes high impedance after 4ms. RST is an open-drain N-channel output. To obtain a voltage output, connect a pullup resistor from RST to OUT. A 100kΩ resistor works well for most applications. RST can be used as a power-on-reset (POR) signal to a microcontroller (µC), or drive an external LED to indicate power failure. When the MAX1792 is shut down, RST is held low independent of the output voltage. If unused, leave RST grounded or unconnected. The MAX1792 monitors and controls the pass transistor’s gate voltage, limiting the output current to 0.8A (typ). This current limit doubles when the output voltage is within 4% of the nominal value to improve performance with large load transients. The output can be shorted to ground for an indefinite period of time without damaging the part. Thermal Overload Protection Thermal overload protection limits total power dissipation in the MAX1792. When the junction temperature exceeds TJ = +170°C, a thermal sensor turns off the pass transistor, allowing the device to cool. The thermal sensor turns the pass transistor on again after the junction temperature cools by 20°C, resulting in a pulsed output during continuous thermal overload conditions. Thermal overload protection protects the MAX1792 in the event of fault conditions. For continuous operation, do not exceed the absolute maximum junction-temperature rating of TJ = +150°C. Operating Region and Power Dissipation The MAX1792’s maximum power dissipation depends on the thermal resistance of the IC package and circuit board, the temperature difference between the die junction and ambient air, and the rate of air flow. The power dissipated in the device is P = IOUT x (VIN - VOUT). The maximum allowed power dissipation is 1.3W or: PMAX = (TJ(MAX) - TA) / ( θJC + θCA) where TJ - TA is the temperature difference between the MAX1792 die junction and the surrounding air, θJC is the thermal resistance from the junction to the case, and θ CA is the thermal resistance from the case through the PC board, copper traces, and other materials to the surrounding air. The MAX1792 package features an exposed thermal pad on its underside. This pad lowers the thermal resistance of the package by providing a direct heat conMaxim Integrated MAX1792 500mA Low-Dropout Linear Regulator in µMAX 0.7 POWER-μMAX PACKAGE OPERATING REGION AT TJ(MAX) = +150°C TA = +50°C CONTINUOUS CURRENT LIMIT 0.5 Noise, PSRR, and Transient Response TYPICAL VDROPOUT LIMIT MAXIMUM OUTPUT CURRENT (A) 0.6 0.1Ω or less to ensure stability and optimum transient response. Surface-mount ceramic capacitors have very low ESR and are commonly available in values up to 10µF. Connect CIN and COUT as close to the MAX1792 as possible to minimize the impact of PC board trace inductance. 0.4 0.3 0.2 TA = +85°C TA = +70°C MAXIMUM SUPPLY VOLTAGE LIMIT (VOUT = 1.25V) 0.1 0 0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 INPUT-OUTPUT VOLTAGE DIFFERENTIAL (V) Figure 3. Power Operating Regions: Maximum Output Current vs. Supply Voltage duction path from the die to the PC board. Additionally, the MAX1792’s ground pin (GND) performs the dual function of providing an electrical connection to system ground and channeling heat away. Connect the exposed backside pad and GND to the system ground using a large pad or ground plane, or multiple vias to the ground plane layer. The MAX1792 delivers up to 0.5A(RMS) and operates with input voltages up to 5.5V, but not simultaneously. High output currents can only be sustained when inputoutput differential voltages are low, as shown in Figure 3. Applications Information Capacitor Selection and Regulator Stability Capacitors are required at the MAX1792’s input and output for stable operation over the full temperature range and with load currents up to 500mA. Connect a 1µF capacitor between IN and ground and a 3.3µF low equivalent series resistance (ESR) capacitor between OUT and ground. For output voltages less than 2V, use a 4.7µF low-ESR output capacitor. The input capacitor (CIN) lowers the source impedance of the input supply. Reduce noise and improve load-transient response, stability, and power-supply rejection by using larger output capacitors such as 10µF. The output capacitor’s (COUT) ESR affects stability and output noise. Use output capacitors with an ESR of Maxim Integrated The MAX1792 is designed to operate with low dropout voltages and low quiescent currents in battery-powered systems while still maintaining good noise, transient response, and AC rejection. See the Typical Operating Characteristics for a plot of Power-Supply Rejection Ratio (PSRR) vs. Frequency. When operating from noisy sources, improved supply-noise rejection and transient response can be achieved by increasing the values of the input and output bypass capacitors and through passive filtering techniques. The MAX1792 load-transient response graphs (see Typical Operating Characteristics) show two components of the output response: a DC shift from the output impedance due to the load current change, and the transient response. A typical transient response for a step change in the load current from 5mA to 500mA is 18mV. Increasing the output capacitor’s value and decreasing the ESR attenuates the overshoot. Input-Output (Dropout) Voltage A regulator’s minimum input-to-output voltage differential (dropout voltage) determines the lowest usable supply voltage. In battery-powered systems, this determines the useful end-of-life battery voltage. Because the MAX1792 uses a P-channel MOSFET pass transistor, its dropout voltage is a function of drain-tosource on-resistance (RDS(ON)) multiplied by the load current (see Typical Operating Characteristics): VDROPOUT = VIN - VOUT = RDS(ON) x IOUT The MAX1792 ground current remains below 150µA in dropout. Note: The MAX1792 has an exposed thermal pad on the bottom side of the package. Package Information For the latest package outline information and land patterns (footprints), go to www.maximintegrated.com/packages. Note that a “+”, “#”, or “-” in the package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing pertains to the package regardless of RoHS status. PACKAGE TYPE PACKAGE CODE OUTLINE NO. LAND PATTERN NO. µMAX-EP U8E+2 21-0107 90-0145 9 MAX1792 500mA Low-Dropout Linear Regulator in µMAX Revision History REVISION NUMBER REVISION DATE DESCRIPTION PAGES CHANGED 0 9/00 Initial release 1 8/08 Updated Pin Description and Package Information 6, 10 — 2 11/11 Updated the Ordering Information and Selector Guide to include lead(Pb)-free and automotive qualified parts; added the soldering information to the Absolute Maximum Ratings section; added the Package Information table 1, 2, 9 Maxim Integrated cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim Integrated product. No circuit patent licenses are implied. Maxim Integrated reserves the right to change the circuitry and specifications without notice at any time. The parametric values (min and max limits) shown in the Electrical Characteristics table are guaranteed. Other parametric values quoted in this data sheet are provided for guidance. 10 ________________________________Maxim Integrated 160 Rio Robles, San Jose, CA 95134 USA 1-408-601-1000 © 2011 Maxim Integrated Products, Inc. Maxim Integrated and the Maxim Integrated logo are trademarks of Maxim Integrated Products, Inc.
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