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19-0269; Rev 0; 9/94
5V/3.3V or Adjustable, Low-Dropout, Low IQ, 500mA Linear Regulators
_______________General Description
The MAX603/MAX604 low-dropout, low quiescent current, linear regulators supply 5V, 3.3V, or an adjustable output for currents up to 500mA. They are available in a 1.8W SO package. Typical dropouts are 320mV at 5V and 500mA, or 240mV at 3.3V and 200mA. Quiescent currents are 15A typ and 35A max. Shutdown turns off all circuitry and puts the regulator in a 2A off mode. A unique protection scheme limits reverse currents when the input voltage falls below the output. Other features include foldback current limiting and thermal overload protection. The output is preset at 3.3V for the MAX604 and 5V for the MAX603. In addition, both devices employ Dual ModeTM operation, allowing user-adjustable outputs from 1.25V to 11V using external resistors. The input voltage supply range is 2.7V to 11.5V. The MAX603/MAX604 feature a 500mA P-channel MOSFET pass transistor. This transistor allows the devices to draw less than 35A over temperature, independent of the output current. The supply current remains low because the P-channel MOSFET pass transistor draws no base currents (unlike the PNP transistors of conventional bipolar linear regulators). Also, when the input-to-output voltage differential becomes small, the internal P-channel MOSFET does not suffer from excessive base current losses that occur with saturated PNP transistors.
____________________________Features
o 500mA Output Current, with Foldback Current Limiting o High-Power (1.8W) 8-Pin SO Package o Dual ModeTM Operation: Fixed or Adjustable Output from 1.25V to 11V o Large Input Range (2.7V to 11.5V) o Internal 500mA P-Channel Pass Transistor o 15A Typical Quiescent Current o 2A (Max) Shutdown Mode o Thermal Overload Protection o Reverse-Current Protection
MAX603/MAX604
______________Ordering Information
PART MAX603CPA MAX603CSA MAX603C/D MAX603EPA MAX603ESA MAX603MJA MAX604CPA MAX604CSA MAX604C/D MAX604EPA MAX604ESA MAX604MJA TEMP. RANGE 0C to +70C 0C to +70C 0C to +70C -40C to +85C -40C to +85C -55C to +125C 0C to +70C 0C to +70C 0C to +70C -40C to +85C -40C to +85C -55C to +125C PIN-PACKAGE 8 Plastic DIP 8 SO Dice* 8 Plastic DIP 8 SO 8 CERDIP** 8 Plastic DIP 8 SO Dice* 8 Plastic DIP 8 SO 8 CERDIP**
________________________Applications
5V and 3.3V Regulators 1.25V to 11V Adjustable Regulators Battery-Powered Devices Pagers and Cellular Phones Portable Instruments Solar-Powered Instruments
* Dice are tested at TA = +25C, DC parameters only. ** Contact factory for availability.
__________Typical Operating Circuit
__________________Pin Configuration
TOP VIEW
IN
OUT
OUTPUT VOLTAGE IN 1 GND 2 COUT 10F GND 3 OFF 4 8 7 OUT GND GND SET
MAX603 MAX604
BATTERY CIN 10F OFF GND SET
MAX603 MAX604
6 5
DIP/SO
TM Dual Mode is a trademark of Maxim Integrated Products.
________________________________________________________________ Maxim Integrated Products 1
Call toll free 1-800-998-8800 for free samples or literature.
5V/3.3V or Adjustable, Low-Dropout, Low IQ, 500mA Linear Regulators MAX603/MAX604
ABSOLUTE MAXIMUM RATINGS
Supply Voltage (IN or OUT to GND).......................-0.3V to +12V Output Short-Circuit Duration ..............................................1 min Continuous Output Current ...............................................600mA SET, OFF Input Voltages ...........................-0.3V to the greater of (IN + 0.3V) or (OUT + 0.3V) Continuous Power Dissipation (TA = +70C) Plastic DIP (derate 9.09mW/C above +70C) ............727mW SO (derate 23.6mW/C above +70C) .............................1.8W CERDIP (derate 8.00mW/C above +70C) .................640mW Operating Temperature Ranges MAX60_C_A ........................................................0C to +70C MAX60_E_A .....................................................-40C to +85C MAX60_MJA ..................................................-55C to +125C Junction Temperature ......................................................+150C Storage Temperature Range .............................-65C to +160C Lead Temperature (soldering, 10sec) .............................+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 = 6V (MAX603) or 4.3V (MAX604), CIN = COUT = 10F, OFF = VIN, SET = GND, TJ = TMIN to TMAX, unless otherwise noted. Typical values are at TJ = +25C.) (Note 1) PARAMETER Input Voltage SYMBOL VIN CONDITIONS MAX60_C SET = OUT, RL = 1k IOUT = 20A to 500mA, 6.0V < VIN < 11.5V IOUT = 20A to 300mA, 4.3V < VIN < 11.5V IOUT = 1mA to 500mA IOUT = 1mA to 300mA Line Regulation VLNR IOUT = 200mA Dropout Voltage (Note 3) VDO IOUT = 500mA IOUT = 200mA IOUT = 400mA Quiescent Current IQ 3.0V VIN 11.5V, SET = OUT OFF 0.4V, RL = 1k, (VOUT + 1V) VIN 11.5V MAX60_E MAX60_M MAX603 MAX604 MAX603C/E MAX603M MAX604 30 7 130 320 240 480 15 0.01 MIN 2.7 2.9 3.0 4.75 3.15 5.00 3.30 60 TYP MAX 11.5 11.5 11.5 5.25 V 3.45 100 150 100 40 220 550 410 820 35 40 2 10 20 2 6 20 350 1200 160 10 mA C C A A A mV mV mV V UNITS
Output Voltage (Note 2)
VOUT
Load Regulation
VLDR
(VOUT + 0.5V) VIN 11.5V, IOUT = 25mA MAX603 MAX604 MAX60_C/E MAX60_M MAX60_C MAX60_E MAX60_M MAX60_C MAX60_E MAX60_M
OFF Quiescent Current
IQ OFF
Minimum Load Current Foldback Current Limit (Note 4) Thermal Shutdown Temperature Thermal Shutdown Hysteresis
IOUT MIN
VIN = 11.5V, SET = OUT VOUT < 0.8V VOUT > 0.8V and VIN - VOUT > 0.7V
ILIM TSD TSD
2
_______________________________________________________________________________________
5V/3.3V or Adjustable, Low-Dropout, Low IQ, 500mA Linear Regulators
ELECTRICAL CHARACTERISTICS (continued)
(VIN = 6V (MAX603) or 4.3V (MAX604), CIN = COUT = 10F, OFF = VIN, SET = GND, TJ = TMIN to TMAX, unless otherwise noted. Typical values are at TJ = +25C.) (Note 1) PARAMETER Reverse-Current Protection Threshold (Note 5) Reverse Leakage Current Start-Up Overshoot Time Required to Exit Shutdown Dual-Mode SET Threshold SET Reference Voltage SET Input Leakage Current OUT Leakage Current SYMBOL VRTH VOUT = 4.5V VOUT = 3.0V VIN = 0V, VOUT = 4.5V (MAX603) VOUT = 3.0V (MAX604) CONDITIONS MAX603 MAX604 MAX60_C IRVL VOSH tSTART VSET TH VSET ISET IOUT LKG VIL OFF OFF Threshold Voltage VIH OFF IOFF en MAX60_E MAX60_M 2 200 80 150 1.16 MAX60_C VIN = 11.5V, VOUT = 2V, SET = OUT Off On, SET = OUT, VIN = 4V On, SET = OUT, VIN = 6V On, SET = OUT, VIN = 11.5V OFF Input Leakage Current Output Noise (Note 6) V OFF = VIN or GND 10Hz to 10kHz, SET = OUT, RL = 1k, COUT = 10F 2.0 3.0 4.0 0.01 250 10 nA VRMS MAX60_E MAX60_M 80 1.20 0.01 0.01 1.24 10 2 6 20 0.4 V A 30 MIN TYP 6 6 0.01 MAX 20 20 10 20 100 %VOUT s mV V nA A UNITS mV
MAX603/MAX604
RL = 1k, COUT = 10F, OFF rise time 1s VIN = 9V, RL = 18, V OFF switched from 0V to VIN, time from 0% to 95% of VOUT For internal feedback For external feedback SET = OUT, RL = 1k VSET = 1.5V or 0V
Note 1: Electrical specifications are measured by pulse testing and are guaranteed for a junction temperature (TJ) equal to the operating temperature range. C and E grade parts may be operated up to a TJ of +125. Expect performance similar to M grade specifications. For TJ between +125C and +150C, the output voltage may drift more. Note 2: (VIN - VOUT) is limited to keep the product (IOUT x (VIN - VOUT)) from exceeding the package power dissipation limits. Note 3: Dropout Voltage is (VIN - VOUT) when VOUT falls to 100mV below its nominal value at VIN = VOUT + 2V. For example, the MAX603 is tested by measuring the VOUT at VIN = 7V, then VIN is lowered until VOUT falls 100mV below the measured value. The difference (VIN - VOUT) is then measured and defined as VDO. Note 4: Foldback Current Limit was characterized by pulse testing to remain below the maximum junction temperature. Note 5: The Reverse-Current Protection Threshold is the output/input differential voltage (VOUT - VIN) at which reverse-current protection switchover occurs and the pass transistor is turned off. Note 6: Noise is tested using a bandpass amplifier with two poles at 10Hz and two poles at 10kHz.
_______________________________________________________________________________________
3
5V/3.3V or Adjustable, Low-Dropout, Low IQ, 500mA Linear Regulators MAX603/MAX604
__________________________________________Typical Operating Characteristics
(VIN = 7V for MAX603, VIN = 5.3V for MAX604, OFF = VIN, SET = GND, CIN = COUT = 10F, RL = 1k, TJ = +25C, unless otherwise noted.)
OUTPUT VOLTAGE vs. LOAD CURRENT
MAX603/4-TOC-01
QUIESCENT CURRENT vs. LOAD CURRENT
MAX603/4-TOC-02
OUTPUT VOLTAGE AND QUIESCENT CURRENT vs. SUPPLY VOLTAGE
MAX603, VOUT = 5V 22 20 MAX604, VOUT = 3.3V 3 2 1 0
MAX1603/4 TOC-03
1.01 NORMALIZED OUTPUT VOLTAGE 1.00 0.99 0.98 0.97 0.96 0.95 0.1 1 10 100
30 QUIESCENT CURRENT (A) 25 20 15 10 5 0 MAX604, VIN = 5.3V, VOUT = 3.3V MAX603, VIN = 12V, VOUT = 10V MAX603, VIN = 7V, VOUT = 5V
6 5 OUTPUT VOLTAGE (V) 4
24
AX I Q, M
X I Q, MA
603
18 16
604
14 12 10
VOUT = 3.3V, 5V, 10V NORMALIZED TO OUTPUT VOLTAGE AT 1mA 700
UPWARD CURVE IS THERMAL EFFECT 0.1 1 10 100 700
8 6 2 3 4 5 6 7 8 9 10 11 12 SUPPLY VOLTAGE (V)
LOAD CURRENT (mA)
LOAD CURRENT (mA)
OUTPUT VOLTAGE vs. TEMPERATURE
MAX603/4-TOC-04
QUIESCENT CURRENT vs. TEMPERATURE
MAX603/4-TOC-05
DROPOUT VOLTAGE vs. LOAD CURRENT
0.8 DROPOUT VOLTAGE (V) 0.7 0.6 0.5 0.4 0.3 0.2 0.1
RD
S( ) ON
NORMALIZED OUTPUT VOLTAGE (%)
103 102 101 100 99 98 97 96 -55 -35 -15 5 25 45
QUIESCENT CURRENT (A)
MAX603 20 15 MAX604
MAX604 VOUT = 3.3V
10
=
1.
2
RD
N S(O )=
MAX603 VOUT = 5V
0.6 5
N)
5
RDS(O
= 0.4
0 65 85 105 125 -55 -35 -15 5 25 45 65 85 105 125 TEMPERATURE (C) TEMPERATURE (C)
0 0 100 200
MAX603, VOUT = 10V, SET EXTERNALLY 300 400 500 600 700 LOAD CURRENT (mA)
10Hz TO 10kHz OUTPUT NOISE
LINE-TRANSIENT RESPONSE
OUTPUT NOISE (1mV/div)
A
B
MAX603 VOUT = 5V 10ms/div
MAX603 VOUT = 5V tR = 10s, tF = 70s 2ms/div A: VIN = 8V (HIGH), VIN = 7V (LOW) B: OUTPUT VOLTAGE (50mV/div)
4
_______________________________________________________________________________________
MAX603/4-TOC-06
104
25
0.9
QUIESCENT CURRENT (A)
5V/3.3V or Adjustable, Low-Dropout, Low IQ, 500mA Linear Regulators
_____________________________Typical Operating Characteristics (continued)
(VIN = 7V for MAX603, VIN = 5.3V for MAX604, OFF = VIN, SET = GND, CIN = COUT = 10F, RL = 1k, TJ = +25C, unless otherwise noted.)
OVERSHOOT AND TIME EXITING SHUTDOWN MODE
MAX603/MAX604
LOAD-TRANSIENT RESPONSE
B A A
5V
B MAX603 VOUT = 5V 2ms/div A: OUTPUT VOLTAGE (100mV/div) B: IOUT = 500mA (HIGH), IOUT = 5mA (LOW) 0V 500s/div A: OFF PIN VOLTAGE (1V/div) RISE TIME = 13s B: MAX603 OUTPUT VOLTAGE (1V/div) DELAY = 4.936ms, OVERSHOOT = 1%, RISE TIME = 55s
______________________________________________________________Pin Description
PIN 1 2, 3, 6, 7 4 5 8 NAME IN GND OFF SET OUT DESCRIPTION Regulator Input. Supply voltage can range from 2.7V to 11.5V. Ground. These pins function as heatsinks, only in the SOIC package. All GND pins must be soldered to the circuit board for proper power dissipation. Connect to large copper pads or planes to channel heat from the IC. Shutdown, active low. Switch logic levels in less than 1s with the high level above the OFF threshold. Feedback for Setting the Output Voltage. Connect to GND to set the output voltage to the preselected 3.3V or 5V. Connect to an external resistor network for adjustable output operation. Regulator Output. Fixed or adjustable from 1.25V to 11.0V. Sources up to 500mA for input voltages above 4V.
1
MAX603 OUT MAX604 2 7 GND GND
IN VIN CIN 10F 3 4 GND OFF GND SET 6 5 R2 R1 COUT 10F RL
8
VOUT
Figure 1. Test Circuit
_______________________________________________________________________________________ 5
5V/3.3V or Adjustable, Low-Dropout, Low IQ, 500mA Linear Regulators MAX603/MAX604
IN SHUTDOWN MOSFET DRIVER WITH FOLDBACK CURRENT LIMIT REVERSE CURRENT PROTECTION
P
ERROR AMP OFF SHUTDOWN LOGIC
OUT SET R1 1.20V REFERENCE THERMAL SENSOR GND DUAL-MODE COMPARATOR 80mV R2
MAX603 MAX604
Figure 2. Functional Diagram
_______________Detailed Description
The MAX603/MAX604 are low-dropout, low-quiescentcurrent linear regulators designed primarily for batterypowered applications. They supply an adjustable 1.25V to 11V output or a preselected 5V (MAX603) or 3.3V (MAX604) output for load currents up to 500mA. As illustrated in Figure 2, they consist of a 1.20V reference, error amplifier, MOSFET driver, P-channel pass transistor, dual-mode comparator, and internal feedback voltage divider. The 1.20V bandgap reference is connected to the error amplifier's inverting input. The error amplifier compares this reference with the selected feedback voltage and amplifies the difference. The MOSFET driver reads the error signal and applies the appropriate drive to the Pchannel pass transistor. If the feedback voltage is lower than the reference, the pass transistor gate is pulled lower, allowing more current to pass and 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 resistor voltage divider connected to the OUT pin, or an external resistor network connected to the SET pin. The dual-mode comparator examines the SET voltage and selects the feedback path used. If SET is below 80mV, internal feedback is used and the output voltage is regulated to 5V for the MAX603 or 3.3V for the MAX604. Additional blocks include a foldback current limiter, reverse current protection, thermal sensor, and shutdown logic.
Internal P-Channel Pass Transistor
The MAX603/MAX604 feature a 500mA P-channel MOSFET pass transistor. This provides several advantages over similar designs using PNP pass transistors, including longer battery life. The P-channel MOSFET requires no base drive, which reduces quiescent current considerably. PNP based regulators waste considerable amounts of current in dropout when the pass transistor saturates. They also use high base-drive currents under large loads. The MAX603/MAX604 do not suffer from these problems and consume only 15A of quiescent current under light and heavy loads, as well as in dropout.
6
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5V/3.3V or Adjustable, Low-Dropout, Low IQ, 500mA Linear Regulators
Output Voltage Selection
The MAX603/MAX604 feature dual-mode operation. In preset voltage mode, the output of the MAX603 is set to 5V and the output of the MAX604 is set to 3.3V using internal, trimmed feedback resistors. Select this mode by connecting SET to ground. In adjustable mode, an output between 1.25V and 11V is selected using two external resistors connected as a voltage divider to SET (Figure 3). The output voltage is set by the following equation: R1 VOUT = VSET 1 + R2 where VSET = 1.20V. To simplify resistor selection: V R1 = R2 OUT - 1 VSET Since the input bias current at SET is nominally zero, large resistance values can be used for R1 and R2 to minimize power consumption without losing accuracy. Up to 1.5M is acceptable for R2. Since the VSET tolerance is less than 40mV, the output can be set using fixed resistors instead of trim pots. In preset voltage mode, impedances between SET and ground should be less than 10k. Otherwise, spurious conditions could cause the voltage at SET to exceed the 80mV dual-mode threshold. > 0.7V. For VIN - VOUT < 0.7V (dropout operation), there is no current limit. If the output voltage drops below 0.8V, implying a short-circuit condition, the output current is limited to 350mA. The output can be shorted to ground for one minute without damaging the device if the package can dissipate V IN x 350mA without exceeding TJ = +150C.
Figure 3. Adjustable Output Using External Feedback Resistors
IN OUT OUTPUT VOLTAGE
MAX603/MAX604
MAX603 MAX604
CIN BATTERY 0.1F to 10F OFF GND SET
R1 COUT 10F RL
R2
Thermal Overload Protection
Thermal overload protection limits total power dissipation in the MAX603/MAX604. When the junction temperature exceeds TJ = +160C, the thermal sensor sends a signal to the shutdown logic, turning off the pass transistor and allowing the IC to cool. The thermal sensor will turn the pass transistor on again after the IC's junction temperature cools by 10C, resulting in a pulsed output during thermal overload conditions. Thermal overload protection is designed to protect the MAX603/MAX604 in the event of fault conditions. For continual operation, the absolute maximum junction temperature rating of TJ = +150C should not be exceeded.
Shutdown
A low input on the OFF pin shuts down the MAX603/ MAX604. In the off mode, the pass transistor, control circuit, reference, and all biases are turned off, reducing the supply current below 2A. OFF should be connected to IN for normal operation. Use a fast comparator, Schmitt trigger, or CMOS or TTL logic to drive the OFF pin in and out of shutdown. Rise times should be shorter than 1s. Do not use slow RC circuits, leave OFF open, or allow the input to linger between thresholds; these measures will prevent the output from jumping to the positive supply rail in response to an indeterminate input state. Since the OFF threshold varies with input supply voltage (see Electrical Characteristics), do not derive the drive voltage from 3.3V logic. With VIN at 11.5V, the high OFF logic level needs to be above 4V.
Operating Region and Power Dissipation
Maximum power dissipation of the MAX603/MAX604 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 resulting maximum power dissipation is: TJ - TA P MAX = JB + BA
Foldback Current Limiting
The MAX603/MAX604 also include a foldback current limiter. It monitors and controls the pass transistor's gate voltage, estimating the output current and limiting it to 1.2A for output voltages above 0.8V and VIN - VOUT
(
(
)
)

where (TJ - TA) is the temperature difference between the MAX603/MAX604 die junction and the surrounding
7
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5V/3.3V or Adjustable, Low-Dropout, Low IQ, 500mA Linear Regulators MAX603/MAX604
POWER DISSIPATION vs. GROUND PAD AREA
MAX603/4 FIG 4
MAXIMUM OUTPUT CURRENT vs. SUPPLY VOLTAGE MAX603
MAXIMUM CONTINUOUS CURRENT LIMIT MAXIMUM SUPPLY VOLTAGE LIMIT MAXIMUM SUPPLY VOLTAGE LIMIT TYPICAL DROPOUT VOLTAGE LIMIT
MAX603/4-FIG-04A MAX603/4-FIG-04B
1.8 1.7 POWER DISSIPATION (W) 1.6 1.5 1.4 1.3 1.2 1.1 1.0 0.2 1.3 1 6.5 10 65 MAX603, VOUT = 5V 8-PIN SO PACKAGE PAPER EPOXY BOARD SINGLE SIDED 1oz. COPPER TJ = +125C TA = +25C STILL AIR
700 MAXIMUM OUTPUT CURRENT (mA) 600 500 400 300 200 100 0 4
HIGH-POWER SOIC
PLASTIC DIP OPERATING REGION AT TA = +25C TJ = +125C 5 6
CERAMIC DIP 13
20 (in2) 130 (cm2)
8 9 10 11 12 7 SUPPLY VOLTAGE (V)
COPPER GROUND PAD AREA
MAX604
MAXIMUM OUTPUT CURRENT (mA)
500 400 300 200 100 0 2
air, JB (or JC) is the thermal resistance of the package chosen, and BA is the thermal resistance through the printed circuit board, copper traces and other materials to the surrounding air. The 8-pin SOIC package for the MAX603/MAX604 features a special lead frame with a lower thermal resistance and higher allowable power dissipation. The thermal resistance of this package is JB = 42C/W, compared with JB = 110C/W for an 8pin plastic DIP package and JB = 125C/W for an 8-pin ceramic DIP package. The GND pins of the MAX603/MAX604 SOIC package perform the dual function of providing an electrical connection to ground and channeling heat away. Connect all GND pins to ground using a large pad or ground plane. Where this is impossible, place a copper plane on an adjacent layer. The pad should exceed the dimensions in Figure 4. Figure 4 assumes the IC is an 8-pin SOIC package, is soldered directly to the pad, has a +125C maximum junction temperature and a +25C ambient air temperature, and has no other heat sources. Use larger pad sizes for other packages, lower junction temperatures, higher ambient temperatures, or conditions where the IC is not soldered directly to the heat-sinking ground pad. The MAX603/MAX604 can regulate currents up to 500mA and operate with input voltages up to 11.5V, but not simultaneously. High output currents can only be sustained when input-output differential voltages are
8
TYPICAL DROPOUT VOLTAGE LIMIT
Figure 4. Typical Maximum Power Dissipation vs. Ground Pad Size.
700 600
MAXIMUM CONTINUOUS CURRENT LIMIT
HIGH-POWER SOIC
PLASTIC DIP OPERATING REGION AT TA = +25C TJ = +125C 3 4
CERAMIC DIP
5 6 7 8 9 10 11 12 13 SUPPLY VOLTAGE (V)
Figure 5. Power Operating Regions: Maximum Output Current vs. Differential Supply Voltage
low, as shown in Figure 5. Maximum power dissipation depends on packaging, board layout, temperature, and air flow. The maximum output current is: IOUT(max ) =
(VIN
PMAX x TJ - TA
(
- VOUT x 100C
)
)
where PMAX is derived from Figure 4.
Reverse-Current Protection
The MAX603/MAX604 has a unique protection scheme that limits reverse currents when the input voltage falls below the output. It monitors the voltages on IN and OUT and switches the IC's substrate and power bus to
_______________________________________________________________________________________
5V/3.3V or Adjustable, Low-Dropout, Low IQ, 500mA Linear Regulators
__________Applications Information
IN OUT OUTPUT VOLTAGE
MAX603/MAX604
Figure 6 illustrates the typical application for the MAX603/MAX604.
BATTERY
CIN
OFF
MAX603 MAX604
COUT 10F SET
Capacitor Selection and Regulator Stability
Normally, use 0.1F to 10F capacitors on the input and 10F on the output of the MAX603/MAX604. The larger input capacitor values provide better supplynoise rejection and line-transient response. Improve load-transient response, stability, and power-supply rejection by using large output capacitors. For stable operation over the full temperature range and with load currents up to 500mA, 10F is recommended. Using capacitors smaller than 3.3F can result in oscillation.
GND
Figure 6. 3.3V or 5V Linear-Regulator Application
Noise
POWER-SUPPLY REJECTION RATIO vs. FREQUENCY
80 70 60 PSRR (dB) 50 40 30 20 10 0 VIN = 1Vp-p FOR f < 400kHz CIN = 0F COUT = 10F 100 101 102 103 IOUT = 100mA
MAX603/4-FIG-06
90 IOUT = 1mA
The MAX603/MAX604 exhibit 3mVp-p to 4mVp-p of noise during normal operation. This is negligible in most applications. When using the MAX603/MAX604 in applications that include analog-to-digital converters of greater than 12 bits, consider the ADC's power-supply rejection specifications. Refer to the output noise plot in the Typical Operating Characteristics.
PSRR and Operation from Sources Other than Batteries
The MAX603/MAX604 are designed to deliver low dropout voltages and low quiescent currents in batterypowered systems. Achieving these objectives requires trading off power-supply noise rejection and swift response to supply variations and load transients. Power-supply rejection is 80dB at low freqencies and rolls off above 10Hz. As the frequency increases above 10kHz, the output capacitor is the major contributor to the rejection of power-supply noise (Figure 7). Do not use power supplies with ripple above 100kHz, especially when the ripple exceeds 100mVp-p. When operating from sources other than batteries, improved supplynoise rejection and transient response can be achieved by increasing the values of the input and output capacitors, and through passive filtering techniques. The Typical Operating Characteristics show the MAX603/ MAX604 supply and load-transient responses.
104
105
106
FREQUENCY (Hz)
Figure 7. Power-Supply Rejection Ratio vs. Ripple Frequency
the more positive of the two. The control circuitry can then remain functioning and turn the pass transistor off, limiting reverse currents back through the device. This feature allows a backup regulator or battery pack to maintain VOUT when the supply at IN fails. Reverse-current protection activates when the voltage on IN falls 6mV (20mV maximum) below the voltage on OUT. Before this happens, currents as high as several milliamperes can flow back through the device. After switchover, typical reverse currents are limited to 0.01A for as long as the condition exists.
Transient Considerations
The Typical Operating Characteristics show the MAX603/MAX604 load-transient response. Two components of the output response can be observed on the load-transient graphs--a DC shift from the output impedance due to the different load currents, and the transient response. Typical transients for step changes in the load current from 5mA to 500mA are 0.2V. Increasing the output capacitor's value attenuates transient spikes.
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_______________________________________________________________________________________
5V/3.3V or Adjustable, Low-Dropout, Low IQ, 500mA Linear Regulators MAX603/MAX604
Input-Output (Dropout) Voltage
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 MAX603/MAX604 use a P-channel MOSFET pass transistor, their dropout voltage is a function of rDS(ON) multiplied by the load current (see Electrical Characteristics). Quickly stepping up the input voltage from the dropout voltage can result in overshoot. This occurs when the pass transistor is fully on at dropout and the IC is not given time to respond to the supply voltage change. Prevent this by slowing the input voltage rise time.
___________________Chip Topography
IN OUT
0.100" (2.54mm)
OFF
GND 0.104" (2.64mm)
SET
TRANSISTOR COUNT: 111 NO DIRECT SUBSTRATE CONNECTION. THE N-SUBSTRATE IS INTERNALLY SWITCHED BETWEEN THE MORE POSITIVE OF IN OR OUT.
10
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5V/3.3V or Adjustable, Low-Dropout, Low IQ, 500mA Linear Regulators
________________________________________________________Package Information
E D A3 A A2 E1
DIM A A1 A2 A3 B B1 C D1 E E1 e eA eB L INCHES MAX MIN 0.200 - - 0.015 0.175 0.125 0.080 0.055 0.022 0.016 0.065 0.045 0.012 0.008 0.080 0.005 0.325 0.300 0.310 0.240 - 0.100 - 0.300 0.400 - 0.150 0.115 INCHES MIN MAX 0.348 0.390 0.735 0.765 0.745 0.765 0.885 0.915 1.015 1.045 1.14 1.265 MILLIMETERS MIN MAX - 5.08 0.38 - 3.18 4.45 1.40 2.03 0.41 0.56 1.14 1.65 0.20 0.30 0.13 2.03 7.62 8.26 6.10 7.87 2.54 - 7.62 - - 10.16 2.92 3.81 MILLIMETERS MIN MAX 8.84 9.91 18.67 19.43 18.92 19.43 22.48 23.24 25.78 26.54 28.96 32.13 MILLIMETERS MIN MAX 1.35 1.75 0.10 0.25 0.35 0.49 0.19 0.25 3.80 4.00 1.27 5.80 6.20 0.40 1.27
MAX603/MAX604
L A1 e B D1
0 - 15 C B1 eA eB
P PACKAGE PLASTIC DUAL-IN-LINE
DIM PINS D D D D D D 8 14 16 18 20 24
DIM
D A e B
0.101mm 0.005in.
0-8
A1
C
L
A A1 B C E e H L
INCHES MAX MIN 0.069 0.053 0.010 0.004 0.019 0.014 0.010 0.007 0.157 0.150 0.050 0.244 0.228 0.050 0.016
E
H
S PACKAGE SMALL OUTLINE
DIM PINS D D D 8 14 16
INCHES MILLIMETERS MIN MAX MIN MAX 0.189 0.197 4.80 5.00 0.337 0.344 8.55 8.75 0.386 0.394 9.80 10.00
21-0041A
______________________________________________________________________________________
11
5V/3.3V or Adjustable, Low-Dropout, Low IQ, 500mA Linear Regulators MAX603/MAX604
___________________________________________Package Information (continued)
DIM INCHES MIN MAX - 0.200 0.014 0.023 0.038 0.065 0.008 0.015 0.220 0.310 0.290 0.320 0.100 0.125 0.200 0.150 - 0.015 0.070 - 0.098 0.005 - MILLIMETERS MIN MAX - 5.08 0.36 0.58 0.97 1.65 0.20 0.38 5.59 7.87 7.37 8.13 2.54 3.18 5.08 3.81 - 0.38 1.78 - 2.49 0.13 -
E1 A D E
Q L e B S1 S B1 L1
0-15 C
A B B1 C E E1 e L L1 Q S S1
DIM PINS
J PACKAGE (0.300 in.) CERDIP DUAL-IN-LINE
D D D D D D
8 14 16 18 20 24
INCHES MILLIMETERS MIN MAX MIN MAX - 0.405 - 10.29 - 0.785 - 19.94 - 0.840 - 21.34 - 0.960 - 24.38 - 1.060 - 26.92 - 1.280 - 32.51
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.
12 __________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 (408) 737-7600 (c) 1994 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.

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