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MAX1857EUA47+T

P1-P3P4-P6P7-P9P10-P10
4.64
4.68
4.76
4.72
4.80
0 200 400 600 800 1000
OUTPUT VOLTAGE
vs. OUTPUT CURRENT
MAX1857 toc01
OUTPUT CURRENT (mA)
OUTPUT VOLTAGE (V)
V
IN
= 5.25V
V
IN
= 5.00V
4.70
4.72
4.76
4.74
4.78
4.80
-55 5-25 35 65 95 125
OUTPUT VOLTAGE vs. TEMPERATURE
MAX1857 toc02
TEMPERATURE (
°
C)
OUTPUT VOLTAGE (V)
I
OUT
= 0mA
0
150
100
50
200
250
300
0 400200 600 800 1000
DROPOUT VOLTAGE
vs. OUTPUT CURRENT
MAX1857 toc03
OUTPUT CURRENT (mA)
DROPOUT VOLTAGE (mV)
T
A
= +25
°
C
T
A
= -40
°
C
T
A
= +85
°
C
Typical Operating Characteristics
(V
IN
= +5.25V, V
OUT
= 4.75V, SHDN = IN, SET = GND, C
IN
= 1µF, C
OUT
= 3.3µF, T
A
= +25°C, unless otherwise noted.)
MAX1857
500mA, Low-Dropout,
Ripple-Rejecting LDO in µMAX
4 _______________________________________________________________________________________
PARAMETER
SYMBOL
CONDITIONS
MIN
UNITS
RESET OUTPUT
Reset Output Low Voltage V
OL
RST sinking 1mA 0.1 V
Operating Voltage Range for
Valid Reset
RST sinking 100µA 1.0 5.5 V
RST Output High Leakage
Current
V
RST
= +5.5V 100 nA
RST Threshold Rising edge, referred to V
OUT(NOMINAL)
83 89 %
RST Release Delay t
RP
Rising edge of OUT to rising edge of RST 1.4 8 ms
ELECTRICAL CHARACTERISTICS (continued)
(V
IN
= +5.25V, V
OUT
= 4.75V, SHDN = IN, SET = GND, T
A
= -40°C to +85°C, unless otherwise noted.) (Note 2)
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 is only meaningful when V
OUT(NOM)
≥ 2.5V. For V
OUT(NOM)
between 2.5V and 3.5V, use the following equations: Typical Dropout = -93mV/V
✕
V
OUT(NOM)
+ 445mV; Guaranteed Maximum
Dropout = -137mV/V
✕
V
OUT(NOM)
+ 704mV. For V
OUT(NOM)
≥ 3.5V: Typical Dropout = 120mV; Guaranteed Maximum Dropout
= 175mV.
Note 2: Specifications to -40°C are guaranteed by design, not production tested.
MAX1857
500mA, Low-Dropout,
Ripple-Rejecting LDO in µMAX
_______________________________________________________________________________________ 5
80
70
60
50
40
30
20
10
0
0.01 1 100.1 100
POWER-SUPPLY REJECTION RATIO
vs. FREQUENCY
MAX1857 toc04
FREQUENCY (kHz)
PSRR (dB)
1000
C
OUT
= 3.3
µ
F
I
OUT
= 50mA
LOAD-TRANSIENT RESPONSE
MAX1857 toc05
10
µ
s/div
4.80V
0
600mA
4.75V
4.70V
400mA
200mA
A: V
OUT
= 4.75V, 50mV/div
B: I
OUT
= 5mA TO 500mA, 200mA/div
V
IN
= 5.25V, C
IN
= 10
µ
F
A
B
LOAD-TRANSIENT RESPONSE
NEAR DROPOUT
MAX1857 toc06
10
µ
s/div
0
4.80V
4.75V
4.70V
4.65V
400mA
200mA
A: V
OUT
= 4.75V, 50mV/div
B: I
OUT
= 5mA TO 500mA, 200mA/div
V
IN
= V
OUT
+ 100mV = 4.85V, C
IN
= 10
µ
F
A
B
SWITCHING POWER-SUPPLY
RIPPLE REJECTION
MAX1857 toc07
2
µ
s/div
5.0V
4.75V
A: MAX1632: V
IN
= 9V, V
OUT
= 5.0V, 20mV/div
B: MAX1857: V
OUT
= 4.75V, I
OUT
= 500mA, 2mV/div
OUT
MAX1632
= IN
MAX1857
A
B
RST WAVEFORM
MAX1857 toc09
20ms/div
A: V
IN
= 0 TO 5.5V, 2V/div
B: V
OUT
= 4.75V, R
OUT
= 95Ω, 2V/div
C: V
RST
, 100kΩ TO OUT, 2V/div
A
B
0
0
0
C
Typical Operating Characteristics (continued)
(V
IN
= +5.25V, V
OUT
= 4.75V, SHDN = IN, SET = GND, C
IN
= 1µF, C
OUT
= 3.3µF, T
A
= +25°C, unless otherwise noted.)
SHUTDOWN WAVEFORM
MAX1857 toc08
40µs/div
6V
2V
A: V
SHDN
= 0 TO 2V, 1V/div
B: V
OUT
= 4.75V, 2V/div
R
OUT
= 9.5Ω (500mA)
A
B
2V
1V
0
4V
0
500mA, Low-Dropout,
Ripple-Rejecting LDO in µMAX
6 _______________________________________________________________________________________
MAX1857
Pin Description
PIN
NAME
FUNCTION
1, 2 IN
Regulator Input. Supply voltage can range from +2.5V to +5.5V. Bypass with a 1µF capacitor or greater to
GND (see Capacitor Selection and Regulator Stability). Connect both input pins together externally.
3
RST
Open-Drain, Active-Low Reset Output. RST remains low while the output voltage (V
OUT
) is below the reset
threshold and for at least 4ms after V
OUT
rises above the reset threshold. Connect a 100kΩ pullup resistor
to OUT.
4 SHDN
Active-Low Shutdown Input. A logic low reduces supply current to 0.1µA. In shutdown, the RST output is
low and OUT is pulled low through an internal 5kΩ resistor. Connect to IN for normal operation.
5 GND Ground
6 SET
Voltage-Setting Input. Connect to GND for preset output. Connect a resistive voltage-divider from OUT to
set the output voltage between 1.25V and 5.0V.
7, 8 OUT
Regulator Output. Sources up to 500mA. Bypass with a 3.3µF low-ESR capacitor to GND. Use a 4.7µF
capacitor for output voltages below 2V. Connect both output pins together.
100mV
SHDN
IN
IN
RST
ON
OFF
C
IN
1µF
V
IN
= +2.5V TO +5.5V
OUT
OUT
V
OUT
= 1.25V TO 5.0V
C
OUT
3.3µF
THERMAL
SENSOR
SET
MOSFET
DRIVER WITH
I
LIM
DELAY
TIMER
SHUTDOWN
LOGIC
V
REF
1.25V
ERROR
AMPLIFIER
GND
R1
R2
R
RST
100kΩ
LOGIC SUPPLY
VOLTAGE (V
OUT
)
86% V
REF
TO
µC
5kΩ
MAX1857
Figure 1. Functional Diagram
P1-P3P4-P6P7-P9P10-P10

MAX1857EUA47+T

Mfr. #:
Buy MAX1857EUA47+T
Manufacturer:
Maxim Integrated
Description:
LDO Voltage Regulators 500mA Ripple-Rejecting
Lifecycle:
New from this manufacturer.
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