Junction Temperature ......................................................+150°C
Operating Temperature Range ...........................-40°C to +85°C
Storage Temperature Range .............................-65°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°C
Soldering Temperature (reflow) .......................................+260°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.
PACKAGE THERMAL CHARACTERISTICS (Note 1)
Junction-to-Ambient Thermal Resistance (θ
JA
)...............140°C/W
Note 1:
Package thermal resistances were obtained using the method described in JEDEC specification JESD51-7, using a four-layer
board. For detailed information on package thermal considerations, refer to
www.maximintegrated.com/thermal-tutorial.
(Circuit of Figure 1, V
IN
= V
OUT
+ 1V,
SHDN
= IN, I
OUT
= 1mA, T
A
= -40°C to +85°C, unless otherwise noted. Typical values are at
T
A
= +25°C.) (Note 2)
PARAMETER
Input Voltage Range
Supply Current
Shutdown Supply Current
OUT Voltage Range
FB Voltage
OUT Voltage Accuracy (Note 4)
Line Regulation
Load Regulation
Maximum OUT Current
Dropout Voltage (Note 5)
Foldback Current Limit
SHDN
Input Threshold
SHDN
Input Bias Current
FB Input Bias Current
(MAX1725 only)
IN Reverse Leakage Current
Thermal-Shutdown Threshold
Thermal-Shutdown Hysteresis
∆V
LNR
∆V
LDR
I
OUT
∆V
DO
I
SC
V
IH
V
IL
I
SHDN
I
FB
SYMBOL
V
IN
I
IN
I
IN(SHDN)
V
OUT
V
FB
(Note 3)
V
IN
= 12V
V
SHDN
= 0V, V
IN
= 12V, V
OUT
= 0V
MAX1725 only
MAX1725 only (Note 4)
T
A
= +25°C
T
A
= 0°C to +85°C
T
A
= -40°C to +85°C
V
IN
= 2.5V or (V
OUT
+ 0.5V) to 12V
I
OUT
= 1mA to 20mA, V
IN
= (V
OUT
+ 1V)
or 3V (min)
V
IN
= (V
OUT
+ 1V) or 3V (Note 5)
I
OUT
= 20mA for V
OUT
≥
2.5V, I
OUT
= 10mA for
V
OUT
< 2.5V, not applicable for V
OUT
< 1.9V
V
IN
= 12V, V
OUT
= 0V
V
IN
= 2.5V to 12V
V
SHDN
= 0V to 12V
V
FB
= 1.25V
V
IN
= -12V, V
SHDN
= 0V
Temperature rising
T
A
= +25°C
T
A
= +85°C
T
A
= +25°C
T
A
= +85°C
-20
2
0.5
-50
0.1
2
1.5
0.01
150
15
10
+20
+50
20
-1.5
-2
-3
0.01
0.015
80
300
40
600
1.5
1.245
1.5
+2
+3
0.3
0.15
%/V
%/mA
mA
mV
mA
V
nA
nA
µA
°C
°C
%
CONDITIONS
MIN
2.5
2
0.7
TYP
MAX
12
4.5
2
5
UNITS
V
µA
µA
V
V
ELECTRICAL CHARACTERISTICS
2
Maxim Integrated
MAX1725/MAX1726
12V, Ultra-Low I
Q
, Low-Dropout
Linear Regulators
ELECTRICAL CHARACTERISTICS (continued)
PARAMETER
OUT Line-Transient
Overshoot/Undershoot
OUT Load-Transient
Overshoot/Undershoot
OUT Noise
Note 2:
Note 3:
Note 4:
Note 5:
e
n
SYMBOL
(Circuit of Figure 1, V
IN
= V
OUT
+ 1V,
SHDN
= IN, I
OUT
= 1mA, T
A
= -40°C to +85°C, unless otherwise noted. Typical values are at
T
A
= +25°C.) (Note 2)
CONDITIONS
∆V
IN
= ±0.25V, t
R
= t
F
= 5µs
I
OUT
from 1mA to 10mA, t
R
= t
F
= 1µs
f = 10Hz to 100kHz
MIN
TYP
15
200
350
MAX
UNITS
mV
mV
µV
RMS
Limits are 100% production tested at +25°C. All temperature limits are guaranteed by design.
Guaranteed by OUT line-regulation testing.
OUT accuracy from nominal voltage. The MAX1725 is tested at V
OUT
= 1.5V, 2.5V, and 5V.
When V
OUT
falls to 4% below its value at V
IN
= V
OUT
+ 1V.
Typical Operating Characteristics
(V
OUT
= +3.3V, I
OUT
= 1mA, T
A
= +25°C, unless otherwise noted.)
SUPPLY CURRENT vs. INPUT VOLTAGE
MAX1725/26 toc01
SUPPLY CURRENT vs. LOAD CURRENT
MAX1725/26 toc02
SUPPLY CURRENT vs. TEMPERATURE
V
IN
= 5V
MAX1725/26 toc03
5
5
V
IN
= 5V
5
4
SUPPLY CURRENT (µA)
4
SUPPLY CURRENT (µA)
4
SUPPLY CURRENT (µA)
3
3
3
2
2
2
1
1
1
0
4
5
6
7
8
9
10
11
12
INPUT VOLTAGE (V)
0
0
5
10
LOAD CURRENT (mA)
15
20
0
-40
-20
0
20
40
60
80
TEMPERATURE (°C)
OUTPUT VOLTAGE vs. INPUT VOLTAGE
MAX1725/26 toc04
OUTPUT VOLTAGE vs. LOAD CURRENT
MAX1725/26 toc05
NORMALIZED OUTPUT VOLTAGE
vs. TEMPERATURE
NORMALIZED OUTPUT VOLTAGE (%)
MAX1725/26 toc06
0
NOMINAL OUTPUT = 3.3V
OUTPUT VOLTAGE (%DEVIATION)
-0.2
-0.4
-0.6
-0.8
-1.0
I
LOAD
= 20mA
-1.2
-1.4
4
5
6
7
8
9
10
11
I
LOAD
= 1mA
0.8
OUTPUT VOLTAGE (% DEVIATION)
0.6
0.4
0.2
0
-0.2
-0.4
-0.6
-0.8
NOMINAL OUTPUT = 3.3V
V
IN
= 4.5V
0.30
0.20
0.10
I
OUT
= 1mA
0
-0.10
-0.20
-0.30
12
0
2
4
6
8
10 12 14 16 18 20
-40
-20
0
20
40
60
80
INPUT VOLTAGE (V)
LOAD CURRENT (mA)
TEMPERATURE (°C)
Maxim Integrated
3
MAX1725/MAX1726
12V, Ultra-Low I
Q
, Low-Dropout
Linear Regulators
Typical Operating Characteristics (continued)
(V
OUT
= +3.3V, I
OUT
= 1mA, T
A
= +25°C, unless otherwise noted.)
POWER-SUPPLY REJECTION RATIO
vs. FREQUENCY
MAX1725/26 toc07
MAX1725/26 toc08
DROPOUT VOLTAGE vs. LOAD CURRENT
300
250
DROPOUT VOLTAGE (mV)
200
150
100
50
0
0
5
10
LOAD CURRENT (mA)
15
20
T
A
= -40°C
10
0
0.01
T
A
= +85°C
80
70
60
PSRR (dB)
50
40
30
20
LINE-TRANSIENT RESPONSE
C
OUT
= 1µF
I
OUT
= 1mA
MAX1725/26 toc09
V
IN
= 5V
V
OUT
= 3.3V
R
L
= 3.3kΩ
C
OUT
= 1µF
T
A
= +25°C
V
IN
200mV/div
V
OUT
20mV/div
0.1
1
FREQUENCY (kHz)
10
100
100µs/div
LOAD TRANSIENT
MAX1725/26 toc10
TURN-ON/TURN-OFF RESPONSE
C
OUT
= 1µF
I
OUT
= 1mA
V
SHDN
2V/div
MAX1725/26 toc11
C
OUT
= 1µF
I
OUT
= 1mA - 20mA
I
OUT
20mA/div
V
OUT
100mV/div
V
OUT
1V/div
400µs/div
4ms
Pin Description
PIN
NAME
MAX1725 MAX1726
1
2
3
4
—
5
4
Detailed Description
The MAX1725/MAX1726 are low-dropout, low-quiescent-
current linear regulators designed primarily for battery-
powered applications (Figure 1). The MAX1725 provides
an adjustable output voltage from 1.5V to 5V using an
external resistor-divider. The MAX1726 supplies preset
output voltages of 1.8V, 2.5V, 3.3V, or 5V. These devices
consist of a +1.245V error amplifier, MOSFET driver,
and p-channel pass transistor (Figure 2).
FUNCTION
Supply Voltage Input
Ground
Voltage Output
Feedback Voltage Input
Ground
Active-Low Shutdown Input
1
2
3
—
4
5
IN
GND
OUT
FB
GND
SHDN
Maxim Integrated
MAX1725/MAX1726
12V, Ultra-Low I
Q
, Low-Dropout
Linear Regulators
The error amplifier compares 1.245V to the selected
feedback voltage and amplifies the difference. If the
feedback voltage is lower than 1.245V, the pass-tran-
sistor gate is pulled lower, allowing more current to
pass, and thus increasing the output voltage. If the
feedback voltage is higher than 1.245V, the pass-tran-
sistor gate is driven higher, allowing less current to
pass to the output. The output voltage is fed back
through either an internal resistor voltage-divider con-
nected to OUT (MAX1726) or an external resistor net-
work connected to FB (MAX1725). Additional features
include an output current limiter, reverse-battery protec-
tion, a thermal sensor, and shutdown logic.
INPUT
2.5V TO 12V
C
IN
1µF
IN
OUT
OUTPUT
1.5V TO 5V
C
OUT
1µF
R1
Internal P-Channel Pass Transistor
The MAX1725/MAX1726 feature a p-channel MOSFET
pass transistor. This provides 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 current in
dropout when the pass transistor saturates; they also
use high base-drive currents under large loads. The
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