19-2018; Rev 0; 4/01 500mA, Low-Voltage Linear Regulator in MAX Applications Features Guaranteed 500mA Output Current Output Down to 0.8V Low 175mV Dropout at 500mA 1% Output Voltage Accuracy Preset at 0.8V, 1.5V, 1.8V, 2.5V, or 3.3V Adjustable from 0.8V to 4.5V Power-OK Output Low 210A Ground Current 0.02A Shutdown Current Thermal Overload Protection Output Current Limit Tiny 1.3W, 8-Pin Power-MAX Package Ordering Information PART MAX1806EUA_ _ TEMP. RANGE PIN-PACKAGE -40C to +85C 8 Power-MAX Notebook Computers Cellular and Cordless Telephones Selector Guide PDAs PART AND SUFFIX Palmtop Computers MAX1806EUA33 VOUT (V) TOP MARK 3.3 AAAG AAAH Base Stations MAX1806EUA25 2.5 USB Hubs MAX1806EUA18 1.8 AAAI Docking Stations MAX1806EUA15 1.5 AAAJ MAX1806EUA08 0.8 AAAK Pin Configuration Typical Operating Circuit VIN +2.25V TO +5.5V VOUT 0.8V TO 4.5V IN NC CIN 1F COUT 10F RPOK 100k MAX1806 ON SHDN POK OFF SET TOP VIEW OUT GND IN 1 8 OUT 7 OUT 3 6 SET SHDN 4 5 GND IN 2 MAX1806 TO C POK MAX ________________________________________________________________ Maxim Integrated Products 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. 1 MAX1806 General Description The MAX1806 low-dropout linear regulator operates from a +2.25V to +5.5V supply and delivers a guaranteed 500mA load current with low 175mV dropout. The high-accuracy (1%) output voltage is preset at an internally trimmed voltage (see Selector Guide) or can be adjusted from +0.8V to +4.5V with an external resistive-divider. An internal PMOS pass transistor allows low 210A supply current, making this device ideal for portable equipment such as personal digital assistants (PDAs), cellular phones, cordless phones, and other equipment, including base stations and docking stations. Other features include an active-low, power-OK output that indicates when the output is out of regulation, a 0.02A shutdown mode, short-circuit protection, and thermal shutdown protection. The MAX1806 comes in a miniature 1.3W, 8-pin power-MAX package with a metal pad on the underside of the package. MAX1806 500mA, Low-Voltage Linear Regulator in MAX ABSOLUTE MAXIMUM RATINGS IN, SHDN, POK, SET to GND ...................................-0.3V to +6V OUT to GND ................................................-0.3V to (VIN + 0.3V) Output Short-Circuit Duration.....................................Continuous Continuous Power Dissipation (TA = +70C) 8-Pin Power-MAX (derate 17mW/C above +70C) .......1.3W Operating Temperature .......................................-40C to +85C Junction Temperature ......................................................+150C 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 (VIN = VOUT(SETPOINT) + 500mV or VIN = +2.25V whichever is greater, SET = GND, SHDN = IN, TA = 0C to +85C, unless otherwise noted. Typical values are at TA = +25C.) PARAMETER Input Voltage Input Undervoltage Lockout SYMBOL CONDITIONS VIN VUVLO VOUT TA = +85C, IOUT = 1mA to 500mA TA = 0C to +85C, IOUT = 1mA to 500mA, VIN > VOUT + 0.5V Adjustable Output Voltage SET Voltage Threshold (Adjustable Mode) VSET Maximum Output Current IOUT Short-Circuit Current Limit ILIM Ground-Pin Current ISET IQ Dropout Voltage (Note 1) MAX UNITS 1.85 5.5 V 2.0 2.15 V -1 +1 -1.5 +1.5 -3 +3 0.8 4.5 TA = +85C, IOUT = 100mA 790 810 TA = +85C, IOUT = 1mA to 500mA 786 814 TA = 0C to +85C, IOUT = 1mA to 500mA, VIN > VOUT + 0.5V 774 800 VOUT = 0V VSET = +0.8V mV 700 1400 2300 mA 35 80 125 mV +100 nA -100 210 IOUT = 500mA 575 400 A VOUT = +2.25V 259 384 VOUT = +2.8V 201 315 VOUT = +4.0V 147 255 0 0.125 %/V 35 ppm/mA Line Regulation VLNR VIN from (VOUT + 100mV) to 5.5V, ILOAD = 5mA Load Regulation VLDR IOUT = 1mA to 500mA 15.5 10Hz to 1MHz, COUT = 10F (ESR < 0.1) 300 SHDN = GND, VIN = 5.5V 0.02 Output Voltage Noise V mARMS IOUT = 1mA IOUT = 500mA % 826 500 SET Dual ModeTM Threshold SET Input Bias Current TYP 2.25 Rising, 40mV hysteresis TA = +85C, IOUT = 100mA Output Voltage Accuracy (Preset Mode) MIN mV VRMS SHUTDOWN Shutdown Supply Current SHDN Input Threshold IOFF VIH 1.6 0.6 VIL SHDN Input Bias Current I SHDN SHDN = GND or IN 10 Startup Time TSTART COUT = 10F, time from SHDN high to POK high 40 Dual Mode is a trademark of Maxim Integrated Products, Inc. 2 5 _______________________________________________________________________________________ 100 A V nA s 500mA, Low-Voltage Linear Regulator in MAX (VIN = VOUT(SETPOINT) + 500mV or VIN = +2.25V whichever is greater, SET = GND, SHDN = IN, TA = 0C to +85C, unless otherwise noted. Typical values are at TA = +25C.) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS 5 50 mV 5.5 V 100 nA 96 % POWER-OK POK Output Low Voltage VOL Operating Voltage Range for Valid POK Output Sinking 2mA Sinking 100A 1.0 Output High-Leakage Current VPOK = +5.5V Threshold Rising edge, referred to VOUT(NOMINAL) 90 93 THERMAL PROTECTION Thermal Shutdown Temperature TSHDN 170 C Thermal Shutdown Hysteresis TSHDN 20 C ELECTRICAL CHARACTERISTICS (VIN = VOUT(SETPOINT) + 500mV or VIN = +2.25V whichever is greater, SET = GND, SHDN = IN, TA = -40C to +85C, unless otherwise noted. Typical values are at TA = +25C.) (Note 2) PARAMETER Input Voltage SYMBOL CONDITIONS VIN MIN 5.5 V 2.15 V -4 +4 % 0.8 4.5 V IOUT = 1mA to 500mA 766 834 mV Rising, 40mV hysteresis Output Voltage Accuracy (Preset Mode) VOUT IOUT = 1mA to 500mA Adjustable Output Voltage SET Voltage Threshold (Adjustable Mode) VSET Maximum Output Current IOUT Short-Circuit Current Limit ILIM VOUT = 0V 700 ISET VSET = +0.8V 500 Threshold SET Input Bias Current Ground-Pin Current IQ Dropout Voltage (Note 1) UNITS 2.25 VUVLO SET Dual MAX 1.85 Input Undervoltage Lockout ModeTM TYP mARMS 2500 mA 35 125 mV -100 +100 nA 400 A IOUT = 1mA IOUT = 500mA VOUT = +2.25V 259 384 VOUT = +2.8V 201 315 VOUT = +4.0V 147 255 Line Regulation VLNR VIN from (VOUT + 100mV) to 5.5V, ILOAD = 5mA Load Regulation VLDR -0.175 mV +0.175 %/V IOUT = 1mA to 500mA 35 ppm/mA IOFF SHDN = GND, VIN = 5.5V 5 A VIH 2.5V < VIN < 5.5V VIL 2.5V < VIN < 5.5V 0.6 I SHDN SHDN = GND or IN 100 SHUTDOWN Shutdown Supply Current SHDN Input Threshold SHDN Input Bias Current 1.6 V nA _______________________________________________________________________________________ 3 MAX1806 ELECTRICAL CHARACTERISTICS (continued) ELECTRICAL CHARACTERISTICS (continued) (VIN = VOUT(SETPOINT) + 500mV or VIN = +2.25V whichever is greater, SET = GND, SHDN = IN, TA = -40C to +85C, unless otherwise noted. Typical values are at TA = +25C.) (Note 2) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS 50 mV 5.5 V 100 nA 97 % POWER-OK POK Output Low Voltage VOL Sinking 2mA Operating Voltage Range for Valid POK Output Sinking 100A 1.0 Output High-Leakage Current VPOK = +5.5V Threshold Rising edge, referred to VOUT(NOMINAL) 89 Note 1: Dropout voltage is defined as VIN - VOUT, when VOUT is 100mV below the value of VOUT and when VIN = VOUT(NOM) +0.5V. For 2.25V VOUT 4.0V, dropout voltage limits are linearly interpolated from the values listed. For VOUT < 4.0V, dropout voltage limit is equal to the value for VOUT = 4.0V. Note 2: Specifications to -40C are guaranteed by design, not production tested. Typical Operating Characteristics (MAX1806EUA33, VIN = VOUT + 500mV, SHDN = IN, CIN = 1F, COUT = 10F, TA = +25C, unless otherwise noted.) 1.0 0.5 3.29 3.28 3.27 3.25 LOAD CURRENT (mA) DROPOUT VOLTAGE vs. LOAD CURRENT DROPOUT VOLTAGE vs. OUTPUT VOLTAGE 250 TA = +25C 200 150 100 TA = -40C 0.26 0.24 0.22 0.20 0.18 0.14 0 0 100 200 300 400 500 600 700 800 LOAD CURRENT (mA) 2.0 2.5 3.0 3.5 OUTPUT VOLTAGE (V) 10 35 60 85 GROUND-PIN CURRENT vs. INPUT VOLTAGE 0.16 50 4 0.28 DROPOUT VOLTAGE (V) TA = +85C 300 -15 TEMPERATURE (C) MAX1806 toc05 MAX1806 toc04 350 -40 100 200 300 400 500 600 700 800 INPUT VOLTAGE (V) 400 3.30 3.28 0 4.0 4.5 GROUND-PIN CURRENT (A) 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0 3.31 3.29 3.26 0 3.32 600 550 500 450 400 350 300 250 200 150 100 50 0 IOUT = 500mA MAX1806 toc06 1.5 3.30 VIN = VOUT + 500mV IOUT = 0 3.33 OUTPUT VOLTAGE (V) 3.31 OUTPUT VOLTAGE (V) OUTPUT VOLTAGE (V) IOUT = 500mA 2.0 OUTPUT VOLTAGE vs. TEMPERATURE 3.34 MAX1806 toc02 MAX1806 toc01 IOUT = 0mA 3.0 2.5 OUTPUT VOLTAGE vs. LOAD CURRENT 3.32 MAX1806 toc03 OUTPUT VOLTAGE vs. INPUT VOLTAGE 3.5 DROPOUT VOLTAGE (mV) MAX1806 500mA, Low-Voltage Linear Regulator in MAX IOUT = 0mA 2.0 2.5 3.0 3.5 4.0 4.5 INPUT VOLTAGE (V) _______________________________________________________________________________________ 5.0 5.5 6.0 500mA, Low-Voltage Linear Regulator in MAX GROUND-PIN CURRENT vs. LOAD CURRENT VIN = 3.8V 300 250 200 190 -50 -40 180 170 160 -10 100 200 300 400 500 600 700 800 -40 -15 LOAD CURRENT (A) 10 35 60 0.01 85 0.1 1 10 100 1000 FREQUENCY (kHz) TEMPERATURE (C) OUTPUT SPECTRAL NOISE DENSITY vs. FREQUENCY OUTPUT NOISE DC TO 1MHz COUT = 10F IOUT = 50mA MAX1806 toc10 MAX1806 toc11 10 OUTPUT SPECTRAL NOISE DENSITY (V/Hz) COUT = 10F IOUT = 50mA 0 150 1 VOUT 1mV/div 0.1 0.01 VOUT = 3.3V ROUT = 66 (50mA) 0.001 0.1 1 10 100 1000 20ms/div FREQUENCY (kHz) REGION OF STABLE COUT ESR vs. LOAD CURRENT LOAD-TRANSIENT RESPONSE MAX1806 toc13 100 MAX1806 toc12 0 -30 -20 150 100 MAX1806 toc09 -60 MAX1806 toc08 VIN = VOUT + 500mV IOUT = 0 PSRR (dB) 350 GROUND-PIN CURRENT (A) VIN = 5.5V REGION OF COUT ESR GROUND-PIN CURRENT (A) 450 400 200 MAX1806 toc07 500 POWER-SUPPLY REJECTION RATIO vs. FREQUENCY GROUND-PIN CURRENT vs. TEMPERATURE IOUT 200mA/div 10 COUT = 10F 1 VOUT 20mV/div STABLE REGION 0.1 VIN = VOUT + 500mV CIN = 10F ROUT = 660 TO 6.6 (5mA TO 500mA) 0.01 0 100 200 300 400 500 600 700 800 10s/div FREQUENCY (kHz) _______________________________________________________________________________________ 5 MAX1806 Typical Operating Characteristics (continued) (MAX1806EUA33, VIN = VOUT + 500mV, SHDN = IN, CIN = 1F, COUT = 10F, TA = +25C, unless otherwise noted.) MAX1806 500mA, Low-Voltage Linear Regulator in MAX Typical Operating Characteristics (continued) (MAX1806EUA33, VIN = VOUT + 500mV, SHDN = IN, CIN = 1F, COUT = 10F, TA = +25C, unless otherwise noted.) LOAD-TRANSIENT RESPONSE NEAR DROPOUT LINE-TRANSIENT RESPONSE MAX1806 toc14 MAX1806 toc15 6V VIN 1V/div IOUT 200mA/div 3V VOUT 50mV/div VIN = VOUT + 100mV CIN = 10F ROUT = 660 TO 6.6 (5mA TO 500mA) VOUT 10mV/div 10s/div 200s/div POK WAVEFORM SHUTDOWN WAVEFORM MAX1806 toc17 MAX1806 toc16 5V 2V VSHDN 1V/div VIN 2V/div 0 0 3V VOUT 2V/div 0 VOUT 1V/div VPOK 2V/div 0 0 ROUT = 6.6 (500mA) ROUT = 66 (50mA) 200s/div 20s/div Pin Description PIN 6 NAME FUNCTION 1, 2 IN Regulator Input. Supply voltage can range from +2.25V to +5.5V. Bypass with a 1F capacitor to GND (see Capacitor Selection and Regulation Stability). Connect both input pins together externally. 3 POK Open-Drain, Active-Low Power-OK Output. POK remains low while the output voltage (VOUT) is below the POK threshold. Connect a 100k pullup resistor from POK to OUT. 4 SHDN Active-Low Shutdown Input. A logic low at SHDN reduces supply current to 0.02A. In shutdown, the POK output is low. Connect SHDN 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 SET to GND for preset output. Connect an external resistive voltage-divider from OUT to SET to set the output voltage between 0.8V and 4.5V. The SET regulation voltage is 800mV. 7, 8 OUT Regulator Output. OUT sources up to 500mA. Bypass OUT with a 10F low-ESR capacitor to GND. Connect both OUT pins together externally. _______________________________________________________________________________________ 500mA, Low-Voltage Linear Regulator in MAX The MAX1806 is a low-dropout, low-quiescent-current linear regulator. The device supplies loads up to 500mA and is available with preset output voltages. As illustrated in Figure 1, the MAX1806 includes a 0.8V reference, error amplifier, P-channel pass transistor, and internal feedback voltage-divider. The reference is connected to the error amplifier, which compares it 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 increasing 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 either an internal resistive voltage-divider connected to OUT or an external resistor network connected to SET. The dualmode comparator examines VSET and selects the feedback path. If VSET is below 35mV, the internal feedback path is used, and the output is regulated to the factorypreset voltage. Additional blocks include an output current limiter, thermal sensor, and shutdown logic. Internal P-Channel Pass Transistor The MAX1806 features a 0.4 P-channel MOSFET pass transistor. Unlike similar designs using PNP pass transistors, P-channel MOSFETs require no base drive, which reduces operating current. PNP-based regulators also waste considerable current in dropout when the pass transistor saturates, and use high base-drive currents under large loads. The MAX1806 does not suffer from these problems. Output Voltage Selection The MAX1806'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 MAX1806EUA33 has a preset 3.3V output voltage. The output voltage may also be adjusted by connecting a voltage-divider from OUT to SET (Figure 2). Select R2 in the 25k to 100k range. Calculate R1 with the following equation: R1 = R2 [(VOUT / VSET) - 1] where VSET = 0.8V, and VOUT may range from 0.8V to 4.5V. Shutdown Drive SHDN low to enter shutdown. During shutdown, the output is disconnected from the input, and supply current drops to 0.02A. When in shutdown, POK pulls low. 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. Power-OK Output The POK output pulls low when OUT is less than 93% of the nominal regulation voltage. Once OUT exceeds 93% of the nominal voltage, POK goes high impedance. POK is an open-drain N-channel output. To obtain a logic voltage output, connect a pullup resistor from POK to OUT. A 100k resistor works well for most applications. POK can be used to signal a microcontroller (C), or drive an external LED to indicate power failure. When the MAX1806 is shutdown, POK is held low independent of the output voltage. If unused, leave POK grounded or unconnected. Current Limit The MAX1806 monitors and controls the pass transistor's gate voltage, limiting the output current to 1.4A (typ). 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 MAX1806. When the junction temperature exceeds TJ = +170C, 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 20C, resulting in a pulsed output during continuous thermal overload conditions. Thermal overload protection protects the MAX1806 in the event of fault conditions. For continuous operation, do not exceed the absolute maximum junction-temperature rating of TJ = +150C. Operating Region and Power Dissipation The MAX1806'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 (VIN V OUT ). The maximum allowed power dissipation is 1.3W or: PMAX = (TJ(MAX) - TA) / (JC + CA) where TJ - TA is the temperature difference between the MAX1806 die junction and the surrounding air, JC is the thermal resistance from the junction to the case, and CA is the thermal resistance from the case through the PC board, copper traces, and other materials to the surrounding air. The MAX1806 package features an exposed thermal pad on its underside. This pad lowers the package's thermal resistance by provid- _______________________________________________________________________________________ 7 MAX1806 Detailed Description MAX1806 500mA, Low-Voltage Linear Regulator in MAX VIN +2.25V TO +5.5V IN CIN 1F IN THERMAL SENSOR MOSFET DRIVER WITH ILIM PRESET MODE OUT ON VOUT 0.8V TO 3.3V SHDN OUT OFF SHUTDOWN LOGIC COUT 10F VREF 0.8V ERROR AMPLIFIER LOGIC SUPPLY VOLTAGE (VOUT) RPOK 100k MAX1806 POK TO C SET 93% VREF 80mV GND Figure 1. Functional Diagram ing a direct heat conduction path from the die to the PC board. 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 MAX1806 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 is within the limits outlined. output capacitors. The output capacitor's (COUT) ESR affects stability and output noise. Use output capacitors with an ESR of 0.1 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 10F. Connect CIN and COUT as close to the MAX1806 as possible. Applications Information The MAX1806 is designed to operate with low dropout voltages and low quiescent currents, 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 passivefiltering techniques. The MAX1806 load-transient Capacitor Selection and Regulator Stability Connect a 1F capacitor between IN and ground and a 10F low equivalent series resistance (ESR) capacitor between OUT and ground. 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 8 Noise, PSRR, and Transient Response _______________________________________________________________________________________ 500mA, Low-Voltage Linear Regulator in MAX MAX1806 0.8 IN VOUT 0.8V OUT VIN +2.25V TO +5.5V VOUT IN CIN 1F OUT COUT 10F MAX1806 R1 ON SHDN CONTINUOUS CURRENT LIMIT -1 0.7 MAXIMUM OUTPUT CURRENT (A) R1 = R2 0.6 TA = +50C 0.5 0.4 TA = +85C TA = +70C 0.3 TYPICAL VDROPOUT LIMIT 0.2 POWER-MAX PACKAGE OPERATING REGION AT TJ(MAX) = +150C 0.1 SET OFF 0 0 R2 POK GND 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 INPUT-OUTPUT VOLTAGE DIFFERENTIAL (V) Figure 3. Power Operating Regions: Maximum Output Current vs. Supply Voltage Figure 2. Adjustable Output Using External Feedback Resistors 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 overshoot for a step change in the load current from 5mA to 500mA is 40mV. 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 MAX1806 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) IOUT Chip Information TRANSISTOR COUNT: 949 _______________________________________________________________________________________ 9 500mA, Low-Voltage Linear Regulator in MAX 8L, MAX, EXP PAD.EPS MAX1806 Package Information Note: The MAX1806 has on exposed thermal pad on the bottom side of the package. 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. 10 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 (c) 2001 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.