General Description
The MAX1793 low-dropout linear regulator (LDO) oper-
ates from +2.5V to +5.5V and delivers a guaranteed 1A
load current with a low 210mV dropout. The high-accu-
racy (±1%) output voltage is preset at an internally
trimmed voltage (see the
Ordering Information
) or can
be adjusted from 1.25V to 5.0V with an external resis-
tor-divider.
An internal pMOS pass transistor allows a low 125µA
supply current, making the MAX1793 ideal for battery-
operated portable equipment. Other features include a
built-in reset output, low-power shutdown, and short-cir-
cuit and thermal-overload protection. The MAX1793 is
available in a 1.5W, 16-pin power TSSOP package,
which is 30% smaller than a SOT223 package and only
1.1mm high.
________________________Applications
Notebook Computers
Cordless Telephones
Cellular Phones
Modems
Handheld Instruments
PDAs and Palmtop Computers
Features
oGuaranteed 1A Output Current
oLow 210mV Dropout at 1A
oUp to ±1% Output Voltage Accuracy
Preset at 1.5V, 1.8V, 2.0V, 2.5V, 3.3V or 5.0V
Adjustable from 1.25V to 5.0V
oReset Output (4ms Delay)
oLow 125µA Ground Current
o0.1µA Shutdown
oLow 115µVRMS Output Noise
oThermal-Overload Protection
oOutput Current Limit
oTiny TSSOP Power Package (1.5W)
30% Smaller than SOT223 (only 1.1mm high)
MAX1793
Low-Dropout, Low IQ, 1A Linear Regulator
________________________________________________________________
Maxim Integrated Products
1
16
15
14
13
12
11
10
9
1
2
3
4
5
6
7
8
N.C. N.C.
OUT
OUT
OUT
OUT
SET
GND
N.C.
TOP VIEW
MAX1793
TSSOP
IN
IN
RST
IN
IN
SHDN
N.C. EP
Pin Configuration
NC
MAX1793
IN
IN
IN
IN
IN
OFF
ON
CIN
SHDN
OUT
OUT
OUT
OUT
RST
SET
GND
COUT
OUT
RESET
OUTPUT
Typical Operating Circuit
19-1654; Rev 3; 1/12
Ordering Information
Ordering Information continued at end of data sheet
*
EP = Exposed pad.
†
Contact factory for other preset output voltages.
/V Denotes an automotive qualified part.
Note: Devices are also available in a lead(Pb)-free/RoHS-
compliant package. Specify lead-free by adding “+” to the part
number when ordering.
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.
PART TEMP
RANGE
PIN-
PACKAGE
VOUT†
( V)
MAX1793EUE-50 - 40°C to + 85°C 16 TSSOP-EP* 5.0 or Adj
MAX1793EUE-33 - 40°C to + 85°C 16 TSSOP-EP* 3.3 or Adj
MAX1793EUE-33/V - 40°C to + 85°C 16 TSSOP-EP* 3.3 or Adj
MAX1793
Low-Dropout, Low IQ, 1A Linear Regulator
2 _______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS
(VIN = VOUT(NOM) + 0.5V 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.)
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.
IN, SHDN, RST to GND ............................................-0.3V to +6V
OUT, SET to GND ........................................-0.3V to (VIN + 0.3V)
Output Short-Circuit Duration ............................................Infinite
Continuous Power Dissipation (TA= +70°C)
TSSOP-EP (derate 19mW/°C above +70°C).....................1.5W
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
Soldering Temperature (reflow)
Lead(Pb)-Free Packages..............................................+260°C
Packages Containing Lead(Pb)....................................+240°C
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
Input Voltage VIN 2.5 5.5 V
Input Undervoltage Lockout VIN 2.0 2.3 V
Preset VOUT ≥ 2.5V -1 +1
TA = +85°C,
IOUT = 250mA Preset VOUT < 2.5V -1.5 +1.5
TA = 0°C to +85°C, IOUT = 250mA -2 +2
Output Voltage Accuracy
(Preset Mode, SET = GND)
TA = 0°C to +85°C, IOUT = 1mA to 1A,
VIN > VOUT + 0.5V -3 +3
%
TA = +85°C, IOUT = 250mA, VIN = 3V 1.229 1.250 1.271
TA = 0°C to +85°C, IOUT = 250mA, VIN = 3V 1.219 1.281
SET Voltage Threshold
(For Adjustable Output)
TA = 0°C to + 85°C , IOU T
= 1m A to 1A, V
IN
= 3V 1.212 1.288
V
Adjustable Output Voltage
Range 1.25 5 V
Maximum Output Current IOUT Continuous, VIN ≥ 3V 1 ARM S
Short-Circuit Current Limit ILIM VOUT = 0V, VIN ≥ 3V 1.1 1.8 3.3 A
In-Regulation Current Limit VOUT within 4% of nominal output voltage,
VIN = 5.5V 2.8 A
SET Pin Dual Mode Threshold 50 150 mV
SET Input Bias Current ISET VSET = +1.25V ±100 nA
Ground Current IGND IOUT = 100µA 125 200 µA
MAX1793-33, -50 210 350
Dropout Voltage (Note 1) VIN - VOUT IOUT = 1A,
SET = GND MAX1793-25 270 450 mV
Line Regulation ∆VLNR VIN from (VOUT + 0.1V) to +5.5V,
IOUT = 5mA, SET = GND -0.15 0 +0.15 %/V
Load Regulation ∆VLDR IOUT = 100µA to 1A 0.7 %
Output Voltage Noise 10Hz to 1MHz, COUT = 6.8µF (ESR < 0.1Ω) 115 µVRMS
Shutdown Supply Current IOFF SHDN = GND, VIN = +5.5V 0.1 16 µA
Output Pulldown Resistance in
Shutdown SHDN = GND 5 kΩ
MAX1793
Low-Dropout, Low IQ, 1A Linear Regulator
_______________________________________________________________________________________
3
ELECTRICAL CHARACTERISTICS (continued)
(VIN = VOUT(NOM) + 0.5V 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.)
ELECTRICAL CHARACTERISTICS
(VIN = VOUT(NOM) + 0.5V or VIN = 2.5V (whichever is greater), SHDN = IN, TA= -40°C to +85°C, unless otherwise noted.) (Note 2)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
VIH 1.6
SHDN Input Threshold VIL
+2.5V < VIN < +5.5V 0.6 V
SHDN Input Bias Current I
SHDN SHDN = GND or IN
0.01
1µA
RST Output Low Voltage VOL ISINK = 1mA 0.1 V
Operating Voltage Range for
RST Valid ISINK = 100µA 1.0 5.5 V
RST Output High Leakage V
RST = +5.5V
0.01
1µA
RST Trip Level Referred to
Nominal VOUT Rising edge 90 94 96
% VOUT
RST Release Delay Rising edge 1.5 4.0 8.0 ms
Thermal Shutdown Temperature
T
SHDN Typical thermal hysteresis = 20°C 170 °C
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
Input Voltage VIN 2.5 5.5 V
Input Undervoltage Lockout VIN 2.0 2.3 V
IOUT = 250mA -2.5 2.5
Output Voltage Accuracy
(preset mode, SET = GND) IOUT = 1mA to 1A, VIN > VOUT + 0.5V -3.2 3.2 %
IOUT = 250mA, VIN = 3V 1.216 1.284
SET Voltage Threshold
(for adjustable output) IOUT = 1mA to 1A, VIN = 3V 1.210 1.290 V
Adjustable Output Voltage
Range 1.25 5 V
Maximum Output Current IOUT Continuous, VIN ≥ 3V 1ARMS
Short-Circuit Current Limit ILIM VOUT = 0V, VIN ≥ 3V 1.1 3.3 A
SET Pin Dual Mode Threshold 50 150 mV
SET Input Bias Current ISET VSET = +1.25V ±100 nA
Ground Current IGND IOUT = 100µA 200 µA
MAX1793-33, -50 350
Dropout Voltage (Note 1) VIN -
VOUT
IOUT = 1A,
SET = GND MAX1793-25 450 mV
Line Regulation ∆VLNR VIN from (VOUT + 0.1V) to +5.5V,
IOUT = 5mA, SET = GND -0.15 0.15 %/V
Shutdown Supply Current IOFF SHDN = GND, VIN = +5.5V 16 µA
VIH 1.6
SHDN Input Threshold VIL
+2.5V < VIN < +5.5V
0.6 V
SHDN Input Bias Current I
S H D N SHDN = GND or IN 1 µA
RST Output Low Voltage VOL ISINK = 1mA 0.1 V
1 10 100 1000
OUTPUT VOLTAGE vs. LOAD CURRENT
MAX1793 toc01
LOAD CURRENT (mA)
OUTPUT VOLTAGE (V)
3.305
3.303
3.293
3.295
3.299
3.297
3.301
0
1.0
0.5
2.0
1.5
3.0
2.5
3.5
023145
OUTPUT VOLTAGE vs. INPUT VOLTAGE
MAX1793 toc02
INPUT VOLTAGE (V)
OUTPUT VOLTAGE (V)
IOUT = 0
IOUT = 1A
3.270
3.285
3.280
3.275
3.295
3.290
3.315
3.310
3.305
3.300
3.320
-40 -20 0 20 40 60 80
OUTPUT VOLTAGE vs. TEMPERATURE
MAX1793 toc03
TEMPERATURE (°C)
OUTPUT VOLTAGE (V)
IOUT = 250mA
0
50
150
100
200
250
023145
GROUND CURRENT vs. INPUT VOLTAGE
MAX1793 toc04
INPUT VOLTAGE (V)
GROUND CURRENT (µA)
IOUT = 0
IOUT = 1A
1 10 100 1000
GROUND CURRENT vs. LOAD CURRENT
MAX1793 toc05
LOAD CURRENT (mA)
GROUND CURRENT (µA)
250
225
200
175
150
0
75
50
25
125
100
110
140
130
120
160
150
200
190
180
170
210
-40 -20 0 20
TEMPERATURE (°C)
40 60 80
GROUND CURRENT vs. TEMPERATURE
MAX1793 toc06
GROUND CURRENT (µA)
IOUT = 250mA
IOUT = 0
Typical Operating Characteristics
(Circuit of Figure 2, VIN = +5V, V SHDN = VIN,V
OUT = +3.3V, TA = +25°C, unless otherwise noted.)
MAX1793
Low-Dropout, Low IQ, 1A Linear Regulator
4 _______________________________________________________________________________________
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
Operating Voltage Range for
RST Valid ISINK = 10µA 1.0 5.5 V
RST Output High Leakage V
RST = +5.5V 1µA
RST Trip Level Referred to
Nominal VOUT Rising edge 90 96 % VOUT
RST Release Delay Rising edge 1.5 8.0 ms
ELECTRICAL CHARACTERISTICS (continued)
(VIN = VOUT(NOM) + 0.5V or VIN = 2.5V (whichever is greater), SHDN = IN, TA= -40°C to +85°C, unless otherwise noted.) (Note 2)
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 in only meaningful when VOUT(NOM) ≥2.5V. For VOUT(NOM)
between 2.5V and 3.3V, use the following equations: Typical Dropout = 210mV + (3.3V - VOUT(NOM) x 75mV/V; Guaranteed
Maximum Dropout = 350mV + (3.3V - VOUT(NOM) x 125mV/V. For VOUT(NOM) > 3.3V: Typical Dropout = 210mV;
Guaranteed Maximum Dropout = 350mV.
Note 2: Specifications to TA= -40°C are guaranteed by design and not production tested.
MAX1793
Low-Dropout, Low IQ, 1A Linear Regulator
_______________________________________________________________________________________
5
0
100
50
200
150
250
300
0 600 800200 400 1000 1200
DROPOUT VOLTAGE vs. LOAD CURRENT
MAX1793 toc07
LOAD CURRENT (mA)
DROPOUT VOLTAGE (mV)
60
0
0.01 0.1 1 10 100 1000
POWER-SUPPLY REJECTION RATIO
vs. FREQUENCY
MAX1793 toc08
FREQUENCY (kHz)
PSRR (dB)
10
40
50
30
20
IOUT = 250mA
10
0.01
0.01 0.1 1 10 100 1000
OUTPUT NOISE SPECTRAL DENSITY
vs. FREQUENCY
MAX1793 toc09
FREQUENCY (kHz)
NOISE (µV/√Hz)
1
0.1
IOUT = 250mA
Typical Operating Characteristics (continued)
(Circuit of Figure 2, VIN = +5V, V SHDN = VIN,V
OUT = +3.3V, TA = +25°C, unless otherwise noted.)
140
0
0.001 0.01 0.1 1
OUTPUT NOISE vs. LOAD CURRENT
60
40
MAX1793 toc10
LOAD CURRENT (A)
OUTPUT NOISE (µVRMS)
100
120
20
80
LINE-TRANSIENT RESPONSE
MAX1793 toc11
100µs/div
VIN
5V
3.4V
10mV/div
AC-COUPLED
VOUT
IOUT = 100mA
LOAD-TRANSIENT RESPONSE
MAX1793 toc12
40µs/div
IOUT
1A
100mA
20mV/div
AC-COUPLED
VOUT
OUTPUT NOISE
MAX1793 toc13
4ms/div
100µV/div
MAX1793
Low-Dropout, Low IQ, 1A Linear Regulator
6 _______________________________________________________________________________________
SHUTDOWN RESPONSE
MAX1793 toc14
40µs/div
VOUT
2V/div
5V/div
VSHDN
IOUT = 100mA
RESET OUTPUT RESPONSE
MAX1793 toc15
1ms/div
VIN 5V/div
2V/div
2V/div
VOUT
RST
Typical Operating Characteristics (continued)
(Circuit of Figure 2, VIN = +5V, V SHDN = VIN,V
OUT = +3.3V, TA = +25°C, unless otherwise noted.)
Pin Description
PIN NAME FUNCTION
1, 8, 9, 16 N.C. No Connection. Not internally connected.
2–5 IN
Regulator Input. Supply voltage ranges from +2.5V to +5.5V. Bypass with a 4.7µF capacitor to GND
(see the Capacitor Selection and Regulator Stability). These inputs are internally connected, but they
also must be externally connected for proper operation.
6RST
Reset Output. Open-drain output is low when VOUT is 6% below its nominal value. 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 resister to OUT to obtain an output voltage.
7SHDN
Active-Low Shutdown Input. A logic-low disables the output and reduces the supply current to 0.1µA.
In shutdown, the RST output is low and OUT is pulled low through an internal 5kΩ resistance. Connect
SHDN to IN for normal operation.
10 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.
11 SET Voltage-Setting Input. Connect to GND to select the factory-present output voltage. Connect SET to an
external resistor-divider for adjustable-output operation.
12–15 OUT Regulator Output. Bypass with a 6.8µF, low-ESR capacitor to GND. Connect all OUT pins together at
the IC.
—EP
Exposed Pad. Connect to the ground plane. EP also functions as a heatsink. Solder to the circuit-board
ground plane to maximize thermal dissipation.
Detailed Description
The MAX1793 features Dual Mode™ operation, allow-
ing a fixed output or an adjustable output from +1.25V
to +5V. The regulators are guaranteed to supply 1A of
output current.
As Figure 1 shows, the device consists of a +1.25V ref-
erence, error amplifier, MOSFET driver, p-channel pass
transistor, internal feedback voltage-divider, Dual Mode
comparator, and 4ms reset output.
The +1.25V reference is connected to the inverting
input of the error amplifier. The error amplifier com-
pares 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
p-channel transistor. If the feedback voltage is lower
than the reference, the pass transistor’s gate is pulled
lower, allowing more current to pass and increase the
output voltage. If the feedback voltage is high, the pass
transistor’s gate is pulled up, allowing less current to
pass to the output. The low VOUT comparator senses
when the feedback voltage has dropped 6% below its
expected level, causing RST to go low.
The output voltage is fed back through either an inter-
nal resistor-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.
MAX1793
Low-Dropout, Low IQ, 1A Linear Regulator
_______________________________________________________________________________________ 7
Dual Mode is a trademark of Maxim Integrated Products, Inc.
1175mV
IN
OUT
100mV
NMOS
4ms
4ms DELAY TIMER
R1
R2
PMOS
OUT
SET
GND
SHDN
IN
RST
SHUTDOWN
LOGIC
1.25V
REFERENCE
MOSFET DRIVER
WITH FOLDBACK
CURRENT LIMIT
ERROR AMP
SHUTDOWN
THERMAL
SENSOR
94% VOUT
DETECTOR
DUAL MODE
COMPARATOR
MAX1793
Figure 1. Functional Diagram
MAX1793
Internal p-Channel Pass Transistor
The MAX1793 features a 1A p-channel MOSFET pass
transistor. Unlike similar designs using pnp pass tran-
sistors, p-channel MOSFETs require no base drive,
which reduces quiescent current. pnp-based regula-
tors also waste considerable current in dropout when
the pass transistor saturates and use high base-drive
currents under large loads. The MAX1793 does not suf-
fer from these problems and consumes only 225µA of
quiescent current under heavy loads, as well as in
dropout.
Output Voltage Selection
The MAX1793 features Dual Mode operation. In preset
voltage mode, the output of the MAX1793 is set to an
internally trimmed voltage (see the
Ordering
Information
). Select this mode by connecting SET to
GND (Figure 2).
In adjustable mode, an output is selected between
+1.25V and +5V using two external resistors connected
as a voltage-divider to SET (Figure 3). The output volt-
age is determined by the following equation:
VOUT = VSET [1 + (R1/R2)]
where VSET = +1.25V. To simplify resistor selection:
R1 = R2 [(VOUT/VSET) – 1]
Since the input bias current at SET is less than 100nA,
large resistance values can be used for R1 and R2 to
minimize power consumption without losing efficiency.
Up to 125kΩis acceptable for R2.
In preset voltage mode, the impedance from SET to
GND should be less than 10kΩ. Otherwise, spurious
conditions could cause the voltage at SET to exceed
the 50mV dual-mode threshold.
Shutdown
A logic-low on SHDN disables the MAX1793. In shut-
down, the pass transistor, control circuitry, reference,
and all internal circuits are turned off, reducing supply
current to typically 0.1µA. Connect SHDN to IN for nor-
mal operation. In shutdown, RST goes low and OUT is
discharged to GND with a 5kΩinternal resistance.
RST
Comparator
The MAX1793 features a low VOUT indicator that asserts
when the output voltage falls out of regulation. The
open-drain RST output goes low when OUT falls 6%
below its nominal output voltage. RST remains low for
4ms after OUT has returned to its nominal value. A
100kΩpullup resistor from RST to a suitable logic sup-
ply voltage (typically OUT) provides a logic control sig-
nal. RST can be used as a power-on-reset (POR) signal
to a microcontroller or can drive an external LED to indi-
cate power failure. RST is low during shutdown.
Current Limiting
The MAX1793 features a current limit that monitors the
pass transistor, typically limiting short-circuit output
current to 1.8A. The current limit is increased to
approximately 2.8A when the output voltage is in regu-
lation, improving performance with large transient
loads. The output can be shorted to ground for an
indefinite period of time without damaging the device.
Thermal-Overload Protection
Thermal-overload protection limits total power dissipa-
tion in the MAX1793. When the junction temperature
exceeds TJ= +170°C, a thermal sensor turns off the
pass transistor, allowing the IC to cool. The thermal sen-
sor turns the pass transistor on once the IC’s junction
temperature drops approximately 20°C. Continuous
short-circuit conditions will result in a pulsed output.
Low-Dropout, Low IQ, 1A Linear Regulator
8 _______________________________________________________________________________________
NC
MAX1793
IN
IN
IN
IN
IN
OFF
ON
CIN = 4.7µF
SHDN
OUT
OUT
OUT
OUT
RST
SET
GND
COUT = 6.8µF
OUT
RESET
OUTPUT
Figure 2. Typical Operating Circuit with Preset Output Voltage
NC
MAX1793
IN
IN
IN
IN
IN
OFF
ON
CIN = 4.7µF
SHDN
OUT
OUT
OUT
OUT
RST
SET
GND
R2
R1
COUT = 6.8µF
OUT
RESET
OUTPUT
Figure 3. Typical Operating Circuit with Adjustable Output
Voltage
Thermal-overload protection is designed to safeguard
the MAX1793 in the event of fault conditions. For con-
tinuous operation, do not exceed the absolute maxi-
mum junction-temperature rating of TJ= +150°C.
Operating Region and Power Dissipation
Maximum power dissipation of the MAX1793 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 dis-
sipated by the device is: P = IOUT (VIN – VOUT). The
resulting maximum power dissipation is:
PMAX = [(TJ(MAX) – TA)/(θJC + θCA)]
where (TJ(MAX) – TA) is the temperature difference
between the maximum allowed die junction (+150°C) and
the surrounding air, θJC (junction-to-case) is the thermal
resistance of the package chosen, and θCA is the thermal
resistance from the case through the PCB, copper traces,
and other materials to the surrounding air. Figure 4 shows
allowable power dissipation for typical PCBs at +25°C,
+50°C, and +70°C ambient temperatures.
The MAX1793 TSSOP-EP package features an exposed
thermal pad on its underside. This pad lowers the ther-
mal resistance of the package by providing a direct heat
conduction path from the die to the PCB. Additionally,
the ground pin (GND) also channels heat. Connect the
exposed thermal pad and GND to circuit ground by
using a large pad (minimum 1in2recommended), or mul-
tiple vias to the ground plane.
Applications Information
Capacitor Selection
and Regulator Stability
Capacitors are required at the input and output of the
MAX1793. Connect a 4.7µF capacitor between IN and
ground (CIN) and a 6.8µF capacitor between OUT and
ground (COUT). CIN serves only to lower the source
impedance of the input supply and may be smaller than
4.7µF when the MAX1793 is powered from regulated
power supplies or low-impedance batteries.
The output capacitor’s equivalent series resistance (ESR)
affects stability and output noise. COUT ESR should be
0.5Ωor 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. Other low-ESR (< 0.5Ω) capacitors, such as sur-
face-mount tantalum or OS-CON, may also be used.
Connect CIN and COUT as close to the IC as possible to
minimize the impact of PCB trace inductance.
Noise, PSRR, and Transient Response
The MAX1793 output noise is typically 115µVRMS during
normal operation. This is suitably low for most applica-
tions. See the output noise plot in the
Typical Operating
Characteristics
.
The MAX1793 is designed to achieve low dropout volt-
age and low quiescent current in battery-powered sys-
tems 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 very
noisy sources, supply noise rejection and transient
response can be improved by increasing the values of
the input and output capacitors and employing passive
postfiltering.
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. Since a p-channel
MOSFET is used as the pass device, dropout voltage is
the product of RDS(ON) and load current (see the
Electrical Characteristics
and Dropout Voltage vs. Load
Current in the
Typical Operating Characteristics
). The
MAX1793 operating current typically remains below
225µA in dropout.
MAX1793
Low-Dropout, Low IQ, 1A Linear Regulator
_______________________________________________________________________________________ 9
0
0.6
0.8
1.6
0.4
0.2
1.0
1.2
1.4
1.8
2.0
1032456
MAXIMUM OUTPUT CURRENT vs.
INPUT-OUTPUT DIFFERENTIAL VOLTAGE
INPUT-OUTPUT DIFFERENTIAL VOLTAGE (V)
MAXIMUM OUTPUT CURRENT (A)
MAXIMUM CONTINUOUS CURRENT
MAXIMUM SUPPLY VOLTAGE
TA = +50°C
TJ(MAX) = +150°C
TA = +70°C
TA = +25°C
Figure 4. Power Operating Region: Maximum Output Current
vs. Input-Output Differential Voltage
MAX1793
Low-Dropout, Low IQ, 1A Linear Regulator
10 ______________________________________________________________________________________
Ordering Information (continued)
*
EP = Exposed pad.
†
Contact factory for other preset output voltages.
/V Denotes an automotive qualified part.
Note: Devices are also available in a lead(Pb)-free/RoHS-
compliant package. Specify lead-free by adding “+” to the part
number when ordering.
PART TEMP
RANGE
PIN-
PACKAGE
VOUT†
( V)
MAX1793EUE-25 - 40°C to + 85°C 16 TSSOP-EP* 2.5 or Adj
MAX1793EUE-20 - 40°C to + 85°C 16 TSSOP-EP* 2.0 or Adj
MAX1793EUE-18 - 40°C to + 85°C 16 TSSOP-EP* 1.8 or Adj
MAX1793EUE-15 - 40°C to + 85°C 16 TSSOP-EP* 1.5 or Adj
Package Information
For the latest package outline information and land patterns
(footprints), go to www.maxim-ic.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.
16 TSSOP-EP U16E-3 21-0108 90-0120
MAX1793
Low-Dropout, Low IQ, 1A Linear Regulator
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. 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.
11
____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600
© 2012 Maxim Integrated Products Maxim is a registered trademark of Maxim Integrated Products, Inc.
Revision History
REVISION
NUMBER
REVISION
DATE DESCRIPTION PAGES
CHANGED
0 8/00 Initial release —
1 11/00 Added output voltages and updated Electrical Characteristics. 1–4, 7–9
2 9/09 Added the automotive version of the MAX1793. 1
3 1/12 Added lead-free options and updated soldering temperature and Pin
Description 1, 2, 6, 10
