19-1576; Rev 0; 10/99 150mA, Low-Dropout Linear Regulator with Power-OK Output Features ♦ Optimized for Low-Cost Tantalum Capacitors ♦ Pin Compatible with MIC5206 ♦ Undervoltage Power-OK Output ♦ Preset Output Voltages (±1% accuracy) ♦ Guaranteed 150mA Output Current ♦ 85µA No-Load Supply Current ♦ Low 110mV Dropout at 100mA Load (165mV at 150mA load) ♦ Thermal-Overload and Short-Circuit Protection ♦ Reverse-Battery Protection ♦ 60dB PSRR at 100Hz ♦ 1µA max Shutdown Current Ordering Information Applications PCS Phones Modems PART TEMP. RANGE PIN-PACKAGE Cellular Phones Hand-Held Instruments MAX8885EUK25 -40°C to +85°C 5 SOT23-5 Cordless Phones Palmtop Computers PCMCIA Cards Electronic Planners MAX8885EUK27 MAX8885EUK30 MAX8885EUK33 -40°C to +85°C -40°C to +85°C -40°C to +85°C 5 SOT23-5 5 SOT23-5 5 SOT23-5 MAX8885EUK50 -40°C to +85°C 5 SOT23-5 Output Voltage Selector Guide PART VOUT (V) TOP MARK MAX8885EUK25 2.5 ADLE MAX8885EUK27 MAX8885EUK30 MAX8885EUK33 2.7 3.0 3.3 ADLF ADLG ADLH Note: See Output Voltage Selector Guide for more information. MAX8885EUK50 5.0 ADLJ Note: Other output voltages between 2.5V and 5.0V are available in 100mV increments—contact factory for information. Minimum order quantity is 25,000 units. Typical Operating Circuit OUTPUT PRESET 2.5V TO 5.0V 150mA Pin Configuration INPUT +2.5V TO +6.5V TOP VIEW IN IN 1 GND 2 5 COUT 4.7µF CIN 1µF OUT MAX8885 MAX8885 100k ON OFF SHDN 3 OUT 4 POK POK SHDN TO µC GND SOT23-5 ________________________________________________________________ Maxim Integrated Products 1 For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800. For small orders, phone 1-800-835-8769. MAX8885 General Description The MAX8885 low-dropout (LDO) linear regulator operates from a +2.5V to +6.5V input voltage range and delivers up to 150mA. It uses a P-channel MOSFET pass transistor to allow a low 85µA supply current—which is independent of the load—as well as LDO voltage. The MAX8885 is optimized to operate with low-cost, high-ESR output capacitors such as small case-size tantalum capacitors. It is ideal for cost-sensitive portable equipment such as PCS and cellular phones. For a pin-compatible, functionally equivalent device for use with a low-ESR, ceramic output capacitor, refer to the MAX8875 data sheet. The MAX8885 features a power-OK output that indicates when the output is out of regulation, and is available in preset output voltage versions of 5.0V, 3.3V, 3.0V, 2.7V, and 2.5V. Other features include 1µA (max) shutdown current, short-circuit protection, thermal shutdown protection, and reverse-battery protection. The MAX8885 is available in a miniature 5-pin SOT23 package. MAX8885 150mA, Low-Dropout Linear Regulator with Power-OK Output ABSOLUTE MAXIMUM RATINGS IN, SHDN, POK to GND...............................................-7V to +7V SHDN to IN ...............................................................-7V to +0.3V OUT to GND ................................................-0.3V to (VIN + 0.3V) Output Short-Circuit Duration ........................................Indefinite Continuous Power Dissipation (TA = +70°C) 5-Pin SOT23 (derate 7.1mW/°C above +70°C)..........571mW Operating Temperature Range ...........................-40°C to +85°C Junction Temperature ......................................................+150°C θJA ..................................................................................140°C/W Storage Temperature Range .............................-65°C to +150°C Lead Temperature (soldering, 10s) .................................+300°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(NOMINAL) + 1V, SHDN = IN, TA = -40°C to +85°C, unless otherwise noted. Typical values are at TA = +25°C.) (Note 1) PARAMETER Input Voltage SYMBOL CONDITIONS MAX UNITS 2.5 6.5 V TA = +25°C, IOUT = 100µA -1 1 TA = -40°C to +85°C, IOUT = 100µA -2 2 TA = -40°C to +85°C, IOUT = 100µA to 120mA -3 2 VIN Output Voltage Accuracy MIN Maximum Output Current IOUT 150 Current Limit ILIM 160 Ground Pin Current IQ TYP % mA 390 IOUT = 100µA 85 IOUT = 150mA 100 IOUT = 100µA 0.1 IOUT = 50mA 50 IOUT = 100mA 110 mA 180 µA Dropout Voltage (Note 2) VIN VOUT Line Regulation ∆VLNR VIN = (VOUT + 0.1V) to 6.5V, IOUT = 1mA Load Regulation ∆VLDR IOUT = 100µA to 120mA, COUT = 4.7µF 0.01 %/mA COUT = 10µF, f = 10Hz to 100kHz 170 µVRMS f = 100Hz 60 dB Output Voltage AC PowerSupply Rejection Ratio PSRR mV 165 IOUT = 150mA Output Voltage Noise 220 -0.15 0 0.15 %/V SHUTDOWN Shutdown Supply Current SHDN Input Threshold SHDN Input Bias Current 2 IOFF VIH VIL I SHDN SHDN = GND TA = +25°C 0.005 TA = +85°C 0.02 2.0 VIN = 2.5V to 5.5V V SHDN = 5.5V or GND 1 0.4 TA = +25°C 0 TA = +85°C 0.05 _______________________________________________________________________________________ 100 µA V nA 150mA, Low-Dropout Linear Regulator with Power-OK Output MAX8885 ELECTRICAL CHARACTERISTICS (continued) (VIN = VOUT(NOMINAL) + 1V, SHDN = IN, TA = -40°C to +85°C, unless otherwise noted. Typical values are at TA = +25°C.) (Note 1) PARAMETER SYMBOL CONDITIONS MIN TYP MAX (1 - VOUT / VOUT(NOMINAL))100, VOUT falling, IOUT = 0 -3 -5 -8 UNITS POWER-OK OUTPUT Power-OK Voltage Threshold VPOK 1 Hysteresis, IOUT = 0 POK Output Voltage Low VOL ISINK = 1mA 0 ≤ VPOK ≤ 6.5V, VOUT in regulation POK Output Leakage Current % -5.3 In dropout, VOUT falling 0.4 V 1 µA THERMAL PROTECTION Thermal Shutdown Temperature Thermal Shutdown Hysteresis TSHDN 170 °C ∆TSHDN 20 °C Note 1: Limits are 100% production tested at TA = +25°C. Limits over the operating temperature range are guaranteed through correlation using Statistical Quality Control (SQC) methods. Note 2: Dropout voltage is defined as VIN - VOUT, when VOUT is 100mV below the value of VOUT for VIN = VOUT + 0.5V. Typical Operating Characteristics (MAX8885EUK30, VIN = +3.6V, CIN = 1µF, COUT = 4.7µF, SHDN = IN, TA = +25°C, unless otherwise noted.) GROUND PIN CURRENT vs. OUTPUT LOAD 80 IOUT = 0 60 40 20 110 VIN = 5.0V 105 100 VIN = 3.5V 95 90 0 1 2 3 4 INPUT VOLTAGE (V) 5 6 VIN = VOUT(NOMINAL) + 0.5V 115 VOUT = 5.0V MAX8885EUK50 110 105 100 VOUT = 3.0V MAX8885EUK30 95 90 85 0 120 GROUND PIN CURRENT (µA) 100 115 MAX8885toc02 GROUND PIN CURRENT (µA) IOUT = 150mA GROUND PIN CURRENT (µA) MAX8885toc01 120 GROUND PIN CURRENT vs. OUTPUT LOAD MAX8885toc03 GROUND PIN CURRENT vs. INPUT VOLTAGE 85 0 15 30 45 60 75 90 105 120 135 150 OUTPUT LOAD (mA) 0 15 30 45 60 75 90 105 120 135 150 OUTPUT LOAD (mA) _______________________________________________________________________________________ 3 Typical Operating Characteristics (continued) (MAX8885EUK30, VIN = +3.6V, CIN = 1µF, COUT = 4.7µF, SHDN = IN, TA = +25°C, unless otherwise noted.) OUTPUT VOLTAGE vs. INPUT VOLTAGE 90 VIN = 3.6V OR 5.0V IOUT = 0 80 IOUT = 150mA 1.5 1.0 VIN = 3.6V 2.95 VIN = 5.0V 0 60 -15 10 35 60 2.90 0 85 1 2 3 4 5 TEMPERATURE (°C) INPUT VOLTAGE (V) OUTPUT VOLTAGE vs. TEMPERATURE DROPOUT VOLTAGE vs. OUTPUT LOAD 100 VIN = 3.6V IOUT = 150mA 90 80 65 55 TA = +85°C 50 150 TA = +25°C 100 TA = -40°C 30 0 35 10 COUT = 10µF 40 25 60 -15 45 35 50 -40 ROUT = 60Ω 60 VIN = 5.0V IOUT = 150mA 70 15 30 45 60 75 90 105 120 135 150 OUTPUT LOAD (mA) POWER-SUPPLY REJECTION RATIO vs. FREQUENCY PSRR (dB) VIN = 3.6V OR 5.0V IOUT = 0 110 200 DROPOUT VOLTAGE (mV) 120 0 MAX8885toc08 250 MAX8885toc07 130 6 60 0 85 20 0.01 15 30 45 60 75 90 105 120 135 150 COUT = 1µF 0.1 OUTPUT LOAD (mA) TEMPERATURE (°C) OUTPUT NOISE SPECTRAL DENSITY vs. FREQUENCY 10 100 1000 REGION OF STABLE COUT ESR vs. LOAD CURRENT OUTPUT NOISE (10Hz TO 100kHz) 1000 MAX8885toc11 MAX8885toc10 10 1 FREQUENCY (kHz) MAX8885toc12 -40 COUT ESR (Ω) 100 1 VOUT 500µV/div COUT = 1µF 10 STABLE REGION: COUT = 4.7µF TO 10µF 0.1 1 COUT = 10µF 0.01 COUT = 10µF ILOAD = 50mA IOUT = 50mA 0.1 1 10 FREQUENCY (kHz) 4 3.00 0.5 70 OUTPUT VOLTAGE (V) 2.0 3.05 MAX8885toc09 VIN = 3.6V IOUT = 150mA IOUT = 0 2.5 OUTPUT VOLTAGE (V) 110 100 3.0 3.10 MAX8885toc05 VIN = 5.0V IOUT = 150mA OUTPUT VOLTAGE (V) GROUND PIN CURRENT (µA) 120 OUTPUT VOLTAGE vs. OUTPUT LOAD 3.5 MAX8885toc04 130 MAX8885toc06 GROUND PIN CURRENT vs. TEMPERATURE OUTPUT NOISE SPECTRAL DENSITY (µV/Hz) MAX8885 150mA, Low-Dropout Linear Regulator with Power-OK Output 100 1000 0.1 10ms/div 1 30 60 90 LOAD CURRENT (mA) _______________________________________________________________________________________ 120 150 150mA, Low-Dropout Linear Regulator with Power-OK Output LINE-TRANSIENT RESPONSE LOAD-TRANSIENT RESPONSE NEAR DROPOUT LOAD-TRANSIENT RESPONSE MAX8885toc13 MAX8885toc14 MAX8885toc15 50mA 5V 50mA ILOAD 25mA/div VIN 4V 0 0 VOUT 25mV/div 3.05V 3.02V ILOAD 25mA/div VOUT VOUT 25mV/div 3.05V 3.00V 3.0V 2.98V 3.0V VIN = VOUT + 0.5V CIN = 1µF ROUT = 60Ω 100µs/div 5µs/div 5µs/div POK OUTPUT SHUTDOWN DELAY POK STARTUP RESPONSE MAX8885toc17 MAX8885toc16 3V VOUT 1V/div 0 0 0 2V 0 MAX8885toc18 5V VOUT 2V/div 2.5V VPOK 2V/div 2.5V VIN 2.5V/div 0 VOUT 2.5V/div 0 5V 4V VSHDN 1V/div VIN = VOUT + 0.1V CIN = 1µF VIN 1V/div 3V 2.5V VPOK 2.5V/div 0 2V RLOAD = 60Ω 200µs/div 100µs/div 10ms/div POK AND SHUTDOWN RESPONSE MAX8885toc19 2V VSHDN 0 2V VOUT 0 4V 2V VPOK 0 RLOAD = 60Ω 10µs/div _______________________________________________________________________________________ 5 MAX8885 Typical Operating Characteristics (continued) (MAX8885EUK30, VIN = +3.6V, CIN = 1µF, COUT = 4.7µF, SHDN = IN, TA = +25°C, unless otherwise noted.) 150mA, Low-Dropout Linear Regulator with Power-OK Output MAX8885 Pin Description PIN NAME FUNCTION 1 IN Regulator Input. Supply voltage can range from +2.5V to +6.5V. Bypass with 1µF capacitor to GND (see Capacitor Selection and Regulator Stability). 2 GND Ground. This pin also functions as a heatsink. Solder to a large pad or the circuit-board ground plane to maximize power dissipation. 3 SHDN Active-Low Shutdown Input. A logic low reduces the supply current to below 1µA. Connect to IN for normal operation. 4 POK Power-OK Output. Active low, open-drain output indicates an out-of-regulation condition. Connect a 100kΩ pull-up resistor to OUT for logic levels. If not used, leave this pin unconnected. 5 OUT Regulator Output. Fixed 5.0V, 3.3V, 3.0V, 2.7V, or 2.5V output. Sources up to 150mA. Bypass with 4.7µF (>0.5Ω typ ESR) tantalum capacitor to GND. Detailed Description The MAX8885 is a low-dropout, low-quiescent-current linear regulator designed primarily for battery-powered applications using low-cost, high-ESR tantalum capacitors. The device delivers up to 150mA and is available with preset output voltages of 2.5V, 2.7V, 3.0V, 3.3V, or 5.0V. The MAX8885 consists of a 1.25V reference, error amplifier, P-channel pass transistor, power-OK comparator, and internal feedback voltage divider (Figure 1). The 1.25V bandgap reference is connected to the error amplifier’s inverting input. The error amplifier 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 pass-transistor gate is pulled up, allowing less current to pass to the output. The output voltage is fed back through an internal resistor voltage divider connected to the OUT pin. Additional blocks include a current limiter, reverse-battery protection, thermal sensor, and shutdown logic. Output Voltage The MAX8885 is supplied with factory-set output voltages of 2.5V, 2.7V, 3.0V, 3.3V, or 5.0V. The part number’s two-digit suffix identifies the nominal output voltage. For example, the MAX8885EUK33 indicates a preset output voltage of 3.3V (see Output Voltage Selector Guide). Internal P-Channel Pass Transistor The MAX8885 features a 1.1Ω (typ) P-channel MOSFET pass transistor. This provides several advantages over 6 similar designs using PNP pass transistors, including longer battery life. The P-channel MOSFET requires no base drive, which reduces quiescent current significantly. PNP-based regulators waste considerable current in dropout when the pass transistor saturates. They also use high base-drive currents under large loads. The MAX8885 does not suffer from these problems and consumes only 100µA of quiescent current whether in dropout, light-load, or heavy-load applications (see Typical Operating Characteristics). Power-OK Output (POK) When the output voltage goes out of regulation—as during dropout, current limit, or thermal shutdown—POK goes low. POK is an open-drain N-channel MOSFET. To obtain a logic-level output, connect a pull-up resistor from POK to OUT. To minimize current consumption, make this resistor as large as practical. A 100kΩ resistor works well for most applications. The POK function is not active during shutdown. A capacitor to GND may be added to generate a power-on-reset (POR) delay, which can operate down to V IN ≤ 1V. (See POK Startup Response in the Typical Operating Circuit.) Current Limit The MAX8885 includes a current limiter that monitors and controls the pass transistor’s gate voltage, limiting the output current to 390mA (typ). For design purposes, consider the current limit to be 160mA (min) to 600mA (max). The output can be shorted to ground for an indefinite period of time without damaging the part. Thermal-Overload Protection When the junction temperature exceeds TJ = +170°C, the thermal sensor signals the shutdown logic, turning off the pass transistor and allowing the IC to cool. The _______________________________________________________________________________________ 150mA, Low-Dropout Linear Regulator with Power-OK Output SHDN MAX8885 IN REVERSE BATTERY PROTECTION MOS DRIVER WITH ILIMIT ERROR AMP SHUTDOWN LOGIC P OUT MAX8885 POK THERMAL SENSOR 1.25V REF 95% REF POK GND Figure 1. Functional Diagram thermal sensor will turn the pass transistor on again after the IC’s junction temperature cools by 20°C, resulting in a pulsed output during continuous thermaloverload conditions. Thermal-overload protection is designed to protect the MAX8885 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 MAX8885’s 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 power dissipation across the device is P = IOUT (VIN - VOUT). The maximum power dissipation is: PMAX = (TJ - TA) / ( θJB + θBA) where TJ - TA is the temperature difference between the MAX8885 die junction and the surrounding air; θJB (or θJC) is the thermal resistance of the package; and θBA is the thermal resistance through the printed circuit board, copper traces, and other materials to the surrounding air. The MAX8885’s GND pin performs the dual function of providing an electrical connection to system ground and channeling heat away. Connect GND to the system ground using a large pad or ground plane. Reverse-Battery Protection The MAX8885 has a unique protection scheme that limits the reverse supply current to 1mA when either VIN or V SHDN falls below ground. The circuitry monitors the polarity of these two pins and disconnects the internal circuitry and parasitic diodes when the battery is reversed. This feature prevents device damage. Applications Information Capacitor Selection and Regulator Stability The MAX8885 is designed primarily for applications using low-cost, high-ESR output capacitors such as small case-size tantalum electrolytic capacitors. These capacitors have ESR that can extend as high as 10Ω, and their capacitance and ESR can vary widely over their operating temperature range. For stable operation over the full operating range, use a 4.7µF (1µF min) capacitor with ESR > 0.5Ω (see the Region of Stable C OUT ESR vs. Load Current graph in the Typical Operating Characteristics). Ceramic output capacitors should not be used with the MAX8885. For a pin-compatible, functionally equivalent linear regulator that is suitable for ceramic output capacitors, refer to the MAX8875 data sheet. Bypass the MAX8885’s input with a 1µF or greater capacitor to GND. Place this capacitor close to the device (<5mm). _______________________________________________________________________________________ 7 PSRR and Operation from Sources Other than Batteries put capacitor is chosen to comply with the Region of Stable COUT ESR vs. Load Current graph. The MAX8885 is designed to allow low dropout voltages and low quiescent currents in battery-powered systems. Power-supply rejection is 60dB at low frequencies (see the Power-Supply Rejection Ratio vs. Frequency graph in the Typical Operating Characteristics). Improve supply-noise rejection and transient response by increasing the values of the input and output bypass capacitors. The typical operating characteristics show the MAX8885’s line- and load-transient responses. A regulator’s minimum input-output voltage differential (or dropout voltage) determines the lowest usable supply voltage. In battery-powered systems, this will determine the useful end-of-life battery voltage. Because the MAX8885 uses a P-channel MOSFET pass transistor, its dropout voltage is a function of drain-to-source onresistance (RDS(ON)) multiplied by the load current (see Typical Operating Characteristics). Load-Transient Considerations The MAX8885’s load-transient response graphs (see Typical Operating Characteristics) show three components of the output response. The first (and most significant) component is the abrupt drop in output voltage due to the capacitor’s ESR. The magnitude of the voltage drop is directly proportional to the output capacitor's ESR and the size of the load transient and is independent of the regulator’s transient response. The second component is the output voltage recovery, which is a function of the regulator’s loop response and the capacitance at the output. The third component is a DC shift in the output voltage resulting from the regulator’s finite output impedance. To improve the MAX8885’s load-transient response, increase the output capacitor’s value and decrease its ESR. Take care to ensure that the out- Dropout Voltage VDROPOUT = VIN - VOUT = RDS(ON) · IOUT Chip Information TRANSISTOR COUNT: 266 Package Information SOT5L.EPS MAX8885 150mA, Low-Dropout Linear Regulator with Power-OK Output 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 © 1999 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.
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