19-1654; Rev 3; 1/12
Low-Dropout, Low I
Q
, 1A Linear Regulator
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.
o
Guaranteed 1A Output Current
o
Low 210mV Dropout at 1A
o
Up 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
o
Reset Output (4ms Delay)
o
Low 125µA Ground Current
o
0.1µA Shutdown
o
Low 115µV
RMS
Output Noise
o
Thermal-Overload Protection
o
Output Current Limit
o
Tiny TSSOP Power Package (1.5W)
30% Smaller than SOT223 (only 1.1mm high)
Features
MAX1793
Ordering Information
PART
________________________Applications
Notebook Computers
Cordless Telephones
Cellular Phones
Modems
Handheld Instruments
PDAs and Palmtop Computers
MAX1793EUE-50
MAX1793EUE-33
TEMP
RANGE
PIN-
PACKAGE
V
OUT
†
(V)
-40°C to +85°C 16 TSSOP-EP* 5.0 or Adj
-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
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.
Typical Operating Circuit
TOP VIEW
IN
NC
IN
C
IN
IN
IN
IN
ON
OFF
SET
GND
SHDN
OUT
N.C. 1
OUT
C
OUT
IN 2
IN 3
IN 4
OUT
RST
RESET
OUTPUT
IN 5
RST 6
SHDN 7
N.C. 8
Pin Configuration
16 N.C.
15 OUT
14 OUT
MAX1793
OUT
OUT
MAX1793
13 OUT
12 OUT
11 SET
10 GND
EP
9
N.C.
TSSOP
________________________________________________________________
Maxim Integrated Products
1
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.
Low-Dropout, Low I
Q
, 1A Linear Regulator
MAX1793
ABSOLUTE MAXIMUM RATINGS
IN,
SHDN, RST
to GND ............................................-0.3V to +6V
OUT, SET to GND ........................................-0.3V to (V
IN
+ 0.3V)
Output Short-Circuit Duration ............................................Infinite
Continuous Power Dissipation (T
A
= +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
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
(V
IN
= V
OUT(NOM)
+ 0.5V or V
IN
= 2.5V (whichever is greater),
SHDN
= IN,
T
A
= +0°C to +85°C,
unless otherwise noted. Typical values
are at T
A
= +25°C.)
PARAMETER
Input Voltage
Input Undervoltage Lockout
SYMBOL
V
IN
V
IN
T
A
= +85°C,
I
OUT
= 250mA
Output Voltage Accuracy
(Preset Mode, SET = GND)
Preset V
OUT
≥
2.5V
Preset V
OUT
< 2.5V
CONDITIONS
MIN
2.5
2.0
-1
-1.5
-2
-3
1.229
1.219
1.212
1.25
I
OUT
I
LIM
Continuous, V
IN
≥
3V
V
OUT
= 0V, V
IN
≥
3V
V
OUT
within 4% of nominal output voltage,
V
IN
= 5.5V
50
I
SET
I
GND
V
IN
- V
OUT
∆V
LNR
∆V
LDR
I
OFF
V
SET
= +1.25V
I
OUT
= 100µA
I
OUT
= 1A,
SET = GND
MAX1793-33, -50
MAX1793-25
-0.15
125
210
270
0
0.7
115
0.1
5
16
1
1.1
1.8
2.8
150
±100
200
350
450
+0.15
3.3
1.250
TYP
MAX
5.5
2.3
+1
+1.5
+2
+3
1.271
1.281
1.288
5
V
A
RMS
A
A
mV
nA
µA
mV
%/V
%
µV
RMS
µA
kΩ
V
%
UNITS
V
V
T
A
= 0°C to +85°C, I
OUT
= 250mA
T
A
= 0°C to +85°C, I
OUT
= 1mA to 1A,
V
IN
> V
OUT
+ 0.5V
T
A
= +85°C, I
OUT
= 250mA, V
IN
= 3V
SET Voltage Threshold
(For Adjustable Output)
Adjustable Output Voltage
Range
Maximum Output Current
Short-Circuit Current Limit
In-Regulation Current Limit
SET Pin Dual Mode Threshold
SET Input Bias Current
Ground Current
Dropout Voltage (Note 1)
Line Regulation
Load Regulation
Output Voltage Noise
Shutdown Supply Current
Output Pulldown Resistance in
Shutdown
T
A
= 0°C to +85°C, I
OUT
= 250mA, V
IN
= 3V
T
A
= 0°C to +85°C, I
OUT
= 1mA to 1A, V
IN
= 3V
V
IN
from (V
OUT
+ 0.1V) to +5.5V,
I
OUT
= 5mA, SET = GND
I
OUT
= 100µA to 1A
10Hz to 1MHz, C
OUT
= 6.8µF (ESR < 0.1Ω)
SHDN
= GND, V
IN
= +5.5V
SHDN
= GND
2
_______________________________________________________________________________________
Low-Dropout, Low I
Q
, 1A Linear Regulator
MAX1793
ELECTRICAL CHARACTERISTICS (continued)
(V
IN
= V
OUT(NOM)
+ 0.5V or V
IN
= 2.5V (whichever is greater),
SHDN
= IN,
T
A
= +0°C to +85°C,
unless otherwise noted. Typical values
are at T
A
= +25°C.)
PARAMETER
SHDN
Input Threshold
SHDN
Input Bias Current
RST
Output Low Voltage
Operating Voltage Range for
RST
Valid
RST
Output High Leakage
RST
Trip Level Referred to
Nominal V
OUT
RST
Release Delay
Thermal Shutdown Temperature
T
SHDN
SYMBOL
V
IH
V
IL
I
SHDN
V
OL
CONDITIONS
+2.5V < V
IN
< +5.5V
SHDN
= GND or IN
I
SINK
= 1mA
I
SINK
= 100µA
V
RST
= +5.5V
Rising edge
Rising edge
Typical thermal hysteresis = 20°C
90
1.5
1.0
0.01
94
4.0
170
MIN
1.6
0.01
0.6
1
0.1
5.5
1
96
8.0
TYP
MAX
UNITS
V
µA
V
V
µA
% V
OUT
ms
°C
ELECTRICAL CHARACTERISTICS
(V
IN
= V
OUT(NOM)
+ 0.5V or V
IN
= 2.5V (whichever is greater),
SHDN
= IN,
T
A
= -40°C to +85°C,
unless otherwise noted.) (Note 2)
PARAMETER
Input Voltage
Input Undervoltage Lockout
Output Voltage Accuracy
(preset mode, SET = GND)
SET Voltage Threshold
(for adjustable output)
Adjustable Output Voltage
Range
Maximum Output Current
Short-Circuit Current Limit
SET Pin Dual Mode Threshold
SET Input Bias Current
Ground Current
Dropout Voltage (Note 1)
Line Regulation
Shutdown Supply Current
SHDN
Input Threshold
SHDN
Input Bias Current
RST
Output Low Voltage
I
SET
I
GND
V
IN
-
V
OUT
∆V
LNR
I
OFF
V
IH
V
IL
I
SH D N
V
OL
V
SET
= +1.25V
I
OUT
= 100µA
I
OUT
= 1A,
SET = GND
MAX1793-33, -50
MAX1793-25
-0.15
I
OUT
I
LIM
Continuous, V
IN
≥
3V
V
OUT
= 0V, V
IN
≥
3V
SYMBOL
V
IN
V
IN
I
OUT
= 250mA
I
OUT
= 1mA to 1A, V
IN
> V
OUT
+ 0.5V
I
OUT
= 250mA, V
IN
= 3V
I
OUT
= 1mA to 1A, V
IN
= 3V
CONDITIONS
MIN
2.5
2.0
-2.5
-3.2
1.216
1.210
1.25
1
1.1
50
TYP
MAX
5.5
2.3
2.5
3.2
1.284
1.290
5
UNITS
V
V
%
V
V
A
RMS
3.3
150
±100
200
350
450
0.15
16
1.6
0.6
1
0.1
A
mV
nA
µA
mV
%/V
µA
V
µA
V
V
IN
from (V
OUT
+ 0.1V) to +5.5V,
I
OUT
= 5mA, SET = GND
SHDN
= GND, V
IN
= +5.5V
+2.5V < V
IN
< +5.5V
SHDN
= GND or IN
I
SINK
= 1mA
_______________________________________________________________________________________
3
Low-Dropout, Low I
Q
, 1A Linear Regulator
MAX1793
ELECTRICAL CHARACTERISTICS (continued)
(V
IN
= V
OUT(NOM)
+ 0.5V or V
IN
= 2.5V (whichever is greater),
SHDN
= IN,
T
A
= -40°C to +85°C,
unless otherwise noted.) (Note 2)
PARAMETER
Operating Voltage Range for
RST
Valid
RST
Output High Leakage
RST
Trip Level Referred to
Nominal V
OUT
RST
Release Delay
SYMBOL
I
SINK
= 10µA
V
RST
= +5.5V
Rising edge
Rising edge
90
1.5
CONDITIONS
MIN
1.0
TYP
MAX
5.5
1
96
8.0
UNITS
V
µA
% V
OUT
ms
Note 1:
Dropout voltage is defined as V
IN
- V
OUT
, when V
OUT
is 100mV below the value of V
OUT
measured when V
IN
= V
OUT(NOM)
+
0.5V. Since the minimum input voltage is 2.5V, this specification in only meaningful when V
OUT(NOM)
≥2.5V.
For V
OUT(NOM)
between 2.5V and 3.3V, use the following equations: Typical Dropout = 210mV + (3.3V - V
OUT(NOM)
x 75mV/V; Guaranteed
Maximum Dropout = 350mV + (3.3V - V
OUT(NOM)
x 125mV/V. For V
OUT(NOM)
> 3.3V: Typical Dropout = 210mV;
Guaranteed Maximum Dropout = 350mV.
Note 2:
Specifications to T
A
= -40°C are guaranteed by design and not production tested.
Typical Operating Characteristics
(Circuit of Figure 2, V
IN
= +5V, V
SHDN
= V
IN
, V
OUT
= +3.3V, T
A
= +25°C, unless otherwise noted.)
OUTPUT VOLTAGE vs. LOAD CURRENT
MAX1793 toc01
OUTPUT VOLTAGE vs. INPUT VOLTAGE
MAX1793 toc02
OUTPUT VOLTAGE vs. TEMPERATURE
3.315
3.310
OUTPUT VOLTAGE (V)
3.305
3.300
3.295
3.290
3.285
3.280
I
OUT
= 250mA
MAX1793 toc03
3.305
3.303
OUTPUT VOLTAGE (V)
3.301
3.299
3.297
3.295
3.293
1
10
100
1000
LOAD CURRENT (mA)
3.5
I
OUT
= 0
3.0
OUTPUT VOLTAGE (V)
2.5
2.0
1.5
1.0
0.5
0
0
1
2
3
4
5
INPUT VOLTAGE (V)
I
OUT
= 1A
3.320
3.275
3.270
-40
-20
0
20
40
60
80
TEMPERATURE (°C)
GROUND CURRENT vs. INPUT VOLTAGE
MAX1793 toc04
GROUND CURRENT vs. LOAD CURRENT
MAX1793 toc05
GROUND CURRENT vs. TEMPERATURE
200
190
GROUND CURRENT (µA)
180
170
160
150
140
130
120
110
I
OUT
= 0
I
OUT
= 250mA
MAX1793 toc06
250
I
OUT
= 1A
200
GROUND CURRENT (µA)
250
225
200
GROUND CURRENT (µA)
175
150
125
100
75
50
25
210
150
I
OUT
= 0
100
50
0
0
1
2
3
4
5
INPUT VOLTAGE (V)
0
1
10
100
1000
LOAD CURRENT (mA)
-40
-20
0
20
40
60
80
TEMPERATURE (°C)
4
_______________________________________________________________________________________
Low-Dropout, Low I
Q
, 1A Linear Regulator
MAX1793
Typical Operating Characteristics (continued)
(Circuit of Figure 2, V
IN
= +5V, V
SHDN
= V
IN
, V
OUT
= +3.3V, T
A
= +25°C, unless otherwise noted.)
POWER-SUPPLY REJECTION RATIO
vs. FREQUENCY
MAX1793 toc08
MAX1793 toc07
DROPOUT VOLTAGE vs. LOAD CURRENT
300
250
DROPOUT VOLTAGE (mV)
200
PSRR (dB)
150
100
50
0
0
200
400
1000 1200
LOAD CURRENT (mA)
600
800
60
OUTPUT NOISE SPECTRAL DENSITY
vs. FREQUENCY
MAX1793 toc09
10
I
OUT
= 250mA
50
40
30
20
10
0
0.01
0.1
1
10
100
NOISE (µV/√Hz)
1
0.1
I
OUT
= 250mA
0.01
1000
0.01
0.1
1
10
100
1000
FREQUENCY (kHz)
FREQUENCY (kHz)
OUTPUT NOISE vs. LOAD CURRENT
MAX1793 toc10
LINE-TRANSIENT RESPONSE
MAX1793 toc11
140
120
OUTPUT NOISE (µV
RMS
)
100
5V
V
IN
3.4V
80
60
40
20
0
0.001
0.01
0.1
1
LOAD CURRENT (A)
I
OUT
= 100mA
100µs/div
V
OUT
10mV/div
AC-COUPLED
LOAD-TRANSIENT RESPONSE
MAX1793 toc12
OUTPUT NOISE
MAX1793 toc13
1A
I
OUT
100mA
100µV/div
V
OUT
20mV/div
AC-COUPLED
40µs/div
4ms/div
_______________________________________________________________________________________
5
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