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MAX25307/MAX25308
Two/Three Output Low-Noise LDO Linear
Regulators
General Description
Benefits and Features
The MAX25307/MAX25308 are a two/three output linear
regulator family that deliver up to 600mA on channel 1
and up to 300mA on channels 2 and 3 with only 37µVRMS
of output noise from 10Hz to 100kHz. These regulators
maintain ±1.25% output accuracy over a wide input voltage range, requiring only 155mV (max) of input-to-output
headroom at full load. The 1.95mA maximum no-load supply current is independent of dropout voltage. Each output
is factory programmable between 0.6V to 3.7875V in
12.5mV steps. No external components are needed except for the input, output, and bypass capacitors. Each
output has an independent enable input and RESET output.
● 1.7V to 5.5V Input Voltage Range
● Factory Selectable Output Voltage of 0.6V to 3.7875V
in 12.5mV Steps
● 37μVRMS Output Noise, 10Hz to 100kHz
● 1.95mA (Max) Operating Supply Current
● 70dB PSRR at 10kHz
● 600mA Maximum Output Current (OUT1)
● 300mA Maximum Output Current (OUT2/3)
● ±1.25% DC Accuracy Over Load, Line, and
Temperature
● 155mV (Max) Dropout at IMAX1/2/3 Load (3.3VIN)
● < 1µA Shutdown Supply Current
● Overcurrent and Overtemperature Protection
● Output-to-Input Reversed Current Protection
● Individual RESET Outputs
● 3mm x 3mm 16 pin TQFN Package
● -40ºC to 125ºC Grade 1 Automotive Temperature
Range
Applications
● Infotainment Systems
● Point of Load
● Advanced Driver-Assistance Sytems (ADAS)
Ordering Information appears at end of data sheet.
Simplified Block Diagram
VIN3
VIN2
VIN1
1µF
IN3
IN2
IN1
1µF
4.7µF
BYP1
OUT1
4.7µF
VOUT1
GND
BYP2
EN1
EN2
EN3
OUT2
RESET1
RESET2
RESET3
BYP3
OUT3
EP
19-101040; Rev 0; 4/21
10nF
10nF
2.2µF
VOUT2
10nF
VOUT3
2.2µF
MAX25307/MAX25308
Two/Three Output Low-Noise LDO Linear
Regulators
TABLE OF CONTENTS
General Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Benefits and Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Simplified Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Absolute Maximum Ratings. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Recommended Operating Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Package Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
TQFN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Electrical Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Typical Operating Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Pin Configurations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
MAX25308 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
MAX25307 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Pin Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Functional Diagrams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Simplified Functional Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Detailed Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Supply Inputs (IN1-3) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Enable (EN1-3) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Bypass (BYP) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Overcurrent Protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Overtemperature Protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Output-to-Input Reverse Current Protection. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
RESET Outputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Input Capacitor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Output Capacitor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Thermal Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Typical Application Circuits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Circuit 1 (MAX25308) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Circuit 2 (MAX25307) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Ordering Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Revision History . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
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Maxim Integrated | 2
MAX25307/MAX25308
Two/Three Output Low-Noise LDO Linear
Regulators
Absolute Maximum Ratings
IN1, IN2, IN3, EN1, EN2, EN3 to GND..................... -0.3V to +6V
OUT1 to GND .................................................-0.3V to IN1 + 0.3V
OUT2 to GND .................................................-0.3V to IN2 + 0.3V
OUT3 to GND .................................................-0.3V to IN3 + 0.3V
BYP1, BYP2, BYP3 to GND ..................................... -0.3V to +6V
RESET1,RESET2,RESET3 to GND ........................ -0.3V to +6V
Output Short-Circuit Duration ..................................... Continuous
Package Thermal Characteristics
T1633+7C
Continuous Power Dissipation
TQFN (derate 21.52mW/°C above 70°C) .......1721.69mW
Operating Junction Temperature ................-40°C to +150°C
Storage Temperature Range .......................-65°C to +150°C
Lead Temperature (Soldering, 10 seconds) ..............+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.
Recommended Operating Conditions
PARAMETER
SYMBOL
CONDITION
Ambient Temperature Range
TYPICAL
RANGE
UNIT
-40 to
+125
°C
Note: These limits are not guaranteed.
Package Information
TQFN
Package Code
T1633+7C
Outline Number
21-0136
Land Pattern Number
90-0032
Thermal Resistance, Four-Layer Board:
Junction to Ambient (θJA)
46.47°C/W
Junction to Case (θJC)
5.58°C/W
For the latest package outline information and land patterns (footprints), go to www.maximintegrated.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 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.
Electrical Characteristics
(VIN1,2 = 3.3V, VIN3 = 3.6V, COUT1 = 4.7µF, COUT2,3 = 2.2µF, CBYP_ = 10nF, TJ = -40°C to +150°C, unless otherwise noted. Typical
values are at TA = +25°C under normal conditions, unless otherwise specified. (Note 1) (Note 3))
PARAMETER
Input Voltage Range
Input Undervoltage
Lockout
Input Undervoltage
Lockout Hysteresis
SYMBOL
VIN_
VIN_UVLO
VIN_UVLO_HY
S
CONDITIONS
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IQ_
TYP
MAX
UNITS
Guaranteed by Output Accuracy
1.7
5.5
V
VIN_ rising
1.5
1.69
V
VIN_ UVLO Hysteresis
All outputs off
Supply Current
MIN
IOUT = 0mA, VIN1,2 = 3.3V, VIN3 = 3.6V,
VEN_ = VIN_
100
mV
1
μA
1.2
1.95
mA
Maxim Integrated | 3
MAX25307/MAX25308
Two/Three Output Low-Noise LDO Linear
Regulators
Electrical Characteristics (continued)
(VIN1,2 = 3.3V, VIN3 = 3.6V, COUT1 = 4.7µF, COUT2,3 = 2.2µF, CBYP_ = 10nF, TJ = -40°C to +150°C, unless otherwise noted. Typical
values are at TA = +25°C under normal conditions, unless otherwise specified. (Note 1) (Note 3))
PARAMETER
Output Voltage Range
(Note 4)
Output Accuracy
SYMBOL
VOUT_
ACC
CONDITIONS
MAX
UNITS
0.6
3.7875
V
IOUT_ from 0.1mA to IMAX_, VIN_ from
VOUT_ + 0.3V to 5.5V, VIN_ ≥ 1.7V, -40ºC
< TJ < 125ºC
-1.25
+1.25
IOUT_ from 0.1mA to IMAX_, VIN_ from
VOUT_ + 0.3V to 5.5V, VIN_ ≥ 1.7V, -40ºC
< TJ < 150ºC
-1.5
VIN_ ≥ VOUT_ + 0.3V, VIN_ ≥ 1.7V
MIN
TYP
%
+1.5
Load Regulation
IOUT_ from 0.1mA to IMAX_, VIN_ =
VOUT_ + 0.3V , VOUT1,2,3 = Factory
setting
0.07
%
Line Regulation
VIN_ from VOUT_ + 0.3V to 5.5V, VIN_ ≥
1.7V, IOUT1,2,3 = 0.1mA
0.06
%
LDO_ Dropout Voltage
(Note 2)
VIN_ = 3.3V, IOUT_ = IMAX_
ILIM1_HI
Current Limit
ILIM2,3_HI
Output Noise
Power Supply Rejection
Ratio
EN_ Input Threshold
PSRR
65
155
IMAX1 = 600mA, VIN1 ≥ 1.7V, VOUT1 =
95% of regulation, VIN1 ≥ VOUT1 + 0.3V
650
790
930
IMAX2,3 = 300mA, VIN2,3 ≥ 1.7V, VOUT2,3
= 95% of regulation, VIN2,3 ≥ VOUT2,3 +
0.3V
390
490
590
mV
mA
VOUT_ = 1.2V, IOUT_ = 100mA, 10Hz to
100kHz, CBYP_ = 47nF
37
µVRMS
IOUT1 = 100mA, IOUT2,3 = 50mA, 10kHz
70
dB
VIN_ from 1.7V to
5.5V
EN_ rising
EN_ falling
1.2
0.4
EN_ Hysteresis
V
75
mV
2
MΩ
EN_ Input Resistance
VIN_ from 1.7V to
5.5V
Input Reverse Current
Threshold
Peak reverse current before IIN_ falls to
less than 50μA
200
mA
Thermal Shutdown
Threshold
TJ rising
170
°C
15
ºC
TJ = +25°C
Thermal Shutdown
Hysteresis
Discharge Resistance
VEN_ = 0V
800
Ω
Startup Time
Delay from VEN_ high to VOUT_ starts
rising
220
μs
RESET
RESET_ OV Threshold
VOUT_ rising
104.6
108.3
111.7
RESET_ UV Threshold
VOUT_ falling
88.3
91.7
94.7
%
RESET_ Voltage, Low
IRESET_ = 1mA
10
100
mV
RESET_ Filter Time
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5
%
μs
Maxim Integrated | 4
MAX25307/MAX25308
Two/Three Output Low-Noise LDO Linear
Regulators
Electrical Characteristics (continued)
(VIN1,2 = 3.3V, VIN3 = 3.6V, COUT1 = 4.7µF, COUT2,3 = 2.2µF, CBYP_ = 10nF, TJ = -40°C to +150°C, unless otherwise noted. Typical
values are at TA = +25°C under normal conditions, unless otherwise specified. (Note 1) (Note 3))
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
-0.1
+0.001
+0.1
µA
Option 1
0.425
0.5
0.575
Option 2
2.805
3.7
4.255
Option 3
6.29
7.4
8.51
Option 4
12.665
14.9
17.135
RESET_ Leakage
Current
RESET_ Hold Time
Note 1:
Note 2:
Note 3:
Note 4:
ms
All units are 100% production tested at +25˚C. All temperature limits are guaranteed by design and characterization.
Dropout voltage is defined as (Vin-Vout) when FET is fully turned ON.
The device is designed for continuous operation up to TJ = +125ºC for 95,000 hours and TJ = +150ºC for 5,000 hours.
Not Production Tested, Characterized by ATE.
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Maxim Integrated | 5
MAX25307/MAX25308
Two/Three Output Low-Noise LDO Linear
Regulators
Typical Operating Characteristics
(VIN_ = 3.3V, VOUT1/2/3 = 1.2V/1.8V/3.3V, TA = 25°C, CIN1 = 4.7µF, CIN2,3 = 1µF, COUT1 = 4.7µF, COUT2,3 = 2.2µF, CBYP_ = 10nF,
unless otherwise noted.)
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Maxim Integrated | 6
MAX25307/MAX25308
Two/Three Output Low-Noise LDO Linear
Regulators
Typical Operating Characteristics (continued)
(VIN_ = 3.3V, VOUT1/2/3 = 1.2V/1.8V/3.3V, TA = 25°C, CIN1 = 4.7µF, CIN2,3 = 1µF, COUT1 = 4.7µF, COUT2,3 = 2.2µF, CBYP_ = 10nF,
unless otherwise noted.)
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Maxim Integrated | 7
MAX25307/MAX25308
Two/Three Output Low-Noise LDO Linear
Regulators
Typical Operating Characteristics (continued)
(VIN_ = 3.3V, VOUT1/2/3 = 1.2V/1.8V/3.3V, TA = 25°C, CIN1 = 4.7µF, CIN2,3 = 1µF, COUT1 = 4.7µF, COUT2,3 = 2.2µF, CBYP_ = 10nF,
unless otherwise noted.)
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Maxim Integrated | 8
MAX25307/MAX25308
Two/Three Output Low-Noise LDO Linear
Regulators
Pin Configurations
EN3
BYP1
OUT1
EN1
MAX25308
16
15
14
13
+
RESETB1
1
GND
2
12
IN1
11
BYP3
Exposed Pad
RESETB3
3
10
OUT3
RESETB2
4
9
IN3
12
IN1
11
GND
OUT2
BYP2
EN2
OUT1
EN1
8
BYP1
7
IN2
6
GND
5
16
15
14
13
MAX25307
+
RESETB1
1
GND
2
Exposed Pad
RESETB2
4
9
GND
5
6
7
8
EN2
GND
BYP2
10
OUT2
3
IN2
GND
Pin Description
PIN
NAME
FUNCTION
1
RESET1
Active Low RESET for Output 1. RESET1 becomes high impedance when OUT1
is in regulation. Actively pulled down if OUT1 is outside the regulation window. To
obtain a logic signal, connect a pullup resistor from this pin to a supply.
2
GND
Regulator Ground. Bring IN_ and OUT_ bypass capacitor GND connections to this
pin.
MAX25308
MAX25307
1
2
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Maxim Integrated | 9
MAX25307/MAX25308
Two/Three Output Low-Noise LDO Linear
Regulators
Pin Description (continued)
PIN
NAME
FUNCTION
—
RESET3
Active Low RESET for Output 3. RESET3 becomes high impedance when OUT3
is in regulation. Actively pulled down if OUT3 is outside the regulation window. To
obtain a logic signal, connect a pullup resistor from this pin to a supply.
4
4
RESET2
Active Low RESET for Output 2. RESET2 becomes high impedance when OUT2
is in regulation. Actively pulled down if OUT2 is outside the regulation window. To
obtain a logic signal, connect a pullup resistor from this pin to a supply.
5
5
IN2
Regulator Supply Input. Connect to a voltage between 1.7V and 5.5V, and bypass
with a 1µF capacitor from IN2 to GND.
6
6
OUT2
Channel 2 Output. Sources maximum up to 300mA at output regulation voltage.
Bypass with 2.2μF low ESR capacitor from OUT2 to GND.
7
7
BYP2
Bypass Capacitor Input 2. Connect 1nF to 100nF capacitor between OUT2 and
BYP2 to reduce output noise and set the regulator soft-start rate.
8
8
EN2
Enable Input for Channel 2. Connect this pin to a logic signal to enable (VEN2
high) or disable (VEN2 low) the regulator output. Connect to IN_ with 10kΩ pullup
resistor to keep the output enabled whenever a valid supply voltage is present.
9
—
IN3
Regulator Supply Input. Connect to a voltage between 1.7V and 5.5V and bypass
with a 1µF capacitor from IN3 to GND.
10
—
OUT3
Channel 3 Output. Sources maximum up to 300mA at output regulation voltage.
Bypass with 2.2μF low ESR capacitor from OUT3 to GND.
11
—
BYP3
Bypass Capacitor Input 3. Connect 1nF to 100nF capacitor between OUT3 and
BYP3 to reduce output noise and set the regulator soft-start rate.
12
12
IN1
Regulator Supply Input. Connect to a voltage between 1.7V and 5.5V, and bypass
with a 4.7µF capacitor from IN1 to GND.
Enable Input for Channel 1. Connect this pin to a logic signal to enable (VEN1
high) or disable (VEN1 low) the regulator output. Connect to IN_ with a 10kΩ
pullup resistor to keep the output enabled whenever a valid supply voltage is
present.
MAX25308
MAX25307
3
13
13
EN1
14
14
OUT1
Channel 1 Output. Sources up to 600mA at output regulation voltage. Bypass with
4.7μF low ESR capacitor from OUT1 to GND.
15
15
BYP1
Bypass Capacitor Input 1. Connect 1nF to 100nF capacitor between OUT1 and
BYP1 to reduce output noise and set the regulator soft-start rate.
16
—
EN3
Enable Input for Channel 3. Connect this pin to a logic signal to enable (VEN3
high) or disable (VEN3 low) the regulator output. Connect to IN_ with a10kΩ pull
up resistor to keep the output enabled whenever a valid supply voltage is present.
—
3,9,10,11,16
N.C.
Connect to Ground
EP
EP
EP
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Exposed Pad. Connect the exposed pad to a ground plane with low thermal
resistance to ambient to provide best heat sinking.
Maxim Integrated | 10
MAX25307/MAX25308
Two/Three Output Low-Noise LDO Linear
Regulators
Functional Diagrams
Simplified Functional Diagram
IN[1:3]
UVLO
IN[1:3]_UVLO
PORB
PORB
CS
EN[1:3]_I
REF[1:3]
EN_REF
EA
AV
OUT[1:3]
REF[1:3]
OV_REF[1:3]
UV_REF[1:3]
BANDGAP
[1:3]
REVERSE
CURRENT
PROTECTION
BYP[1:3]
THERMAL
SHUTDOWN
IN1
EN_REF
CONTROL
EN[1:3]
2MΩ
EN[1:3]_I
OV_REF[1:3]
OVP
UVP
RESETB[1:3]
RESET
TIMER
GND
UV_REF[1:3]
PORB
IN[1:3]_UVLO
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Maxim Integrated | 11
MAX25307/MAX25308
Two/Three Output Low-Noise LDO Linear
Regulators
Detailed Description
The MAX25307/MAX25308 are a two/three output linear regulator family that deliver up to 600mA on channel 1 and
300mA on channels 2 and 3 with only 37µVRMS of output noise from 10Hz to 100kHz. These regulators maintain ±1.25%
output accuracy over a wide input voltage range, requiring only 155mV (max) of input-to-output headroom at full load.
The 1.95mA maximum no-load supply current is independent of dropout voltage. Each output is factory programmable
between 0.6V to 3.7875V in 12.5mV steps. No external components are needed except for the input, output, and bypass
capacitors. Each output has an independent enable input and RESET outputs. A simplified functional diagram is shown
in Simplified Functional Diagram.
Supply Inputs (IN1-3)
There is a separate supply input for each LDO. However, IN1 powers the common circuitry of the device. This requires
power to the IN1 to be supplied before OUT2 and/or OUT3 can be turned on. If the supply for IN1 comes up last, this
delays the soft-start for the other outputs until after IN1 is above the UVLO. It is acceptable that the enable inputs are
high prior to the input supply being applied.
Enable (EN1-3)
The MAX25307/MAX25308 include individual enable inputs for each output (EN1/EN2/EN3). Pull EN_ low to shut down
the output, or drive EN_ high to enable the output. If a separate enable signal is not available, connect EN_ to IN_ to
keep the output enabled whenever a valid supply voltage is present.
Bypass (BYP)
The capacitor connected from BYP_ to OUT_ filters the noise of the reference, feedback resistors, and regulator input
stage. The slew rate of the output voltage during startup is also determined by the BYP capacitor. A 0.01μF capacitor
sets the slew rate to 5V/ms.
The BYP capacitor value can be adjusted from 0.001μF to 0.1μF to change the startup slew rate according to the
following formula:
(
0.01μF
StartupSlewRate = (5V / ms) × C
BYP_
)
where CBYP_ is in μF.
Overcurrent Protection
The MAX25307/MAX25308 current limit provides protection during output overload or short circuit conditions. If the
output is shorted to GND, the output current is limited to the selected current limit. In such cases, the output falls out of
regulation, and is VOUT = ILIM × RLOAD. In this condition, the pass element dissipates power equals to (VIN - VOUT)
× ILIM, which increases junction temperature. When the junction temperature reaches approximately 170˚C (typ), a
thermal overload circuit turns off the device. When the junction cools to 155˚C (typ), the device is turned on to reestablish
regulation. While the fault persists, the device cycles between the current limit and thermal shutdown.
Overtemperature Protection
Overtemperature protection turns off the device when junction temperature rises to approximately 170˚C (typ). When
junction temperature cools to approximately 155˚C (typ), the output turns back on to reestablish regulation. The thermal
protection circuit can cycle on and off depending on power dissipation, thermal resistance, and ambient temperature.
This cycling limits the power dissipation and protects the device from damage due to overheating.
Output-to-Input Reverse Current Protection
The MAX25307/MAX25308 are also protected against reverse current when the output voltage is higher than the input. If
extra output capacitance is used at the output, a power-down transient at the input would normally cause a large reverse
current through a conventional regulator. The MAX25307/MAX25308 include a reverse voltage detector that trips when
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Maxim Integrated | 12
MAX25307/MAX25308
Two/Three Output Low-Noise LDO Linear
Regulators
IN_ drops 10mV below OUT_, shutting off the regulator and opening the PMOS body diode connection, preventing any
reverse current.
RESET Outputs
The MAX25307/MAX25308 include an open-drain output, RESET for each output that goes low to indicate the output
voltage is out of regulation. Connect a pullup resistor from this pin to an external supply. When the associated EN_ is low
the RESET_ is asserted. The hold time of all reset outputs is factory selectable between 0.5ms and 14.9ms.
Input Capacitor
A 4.7μF ceramic capacitor for channel 1 and 1μF ceramic capacitor for channels 2 and 3 are recommended for the
input. Select a capacitor that maintains its capacitance over temperature and DC bias. Capacitors with X7R temperature
characteristics generally perform well.
Output Capacitor
The minimum output capacitance for stability depends on the current configuration of the channel. See the following table
for the capacitance requirements based on the output current capability.
COUT(MIN)
COUT(TYP)
(μF)
(μF)
600mA
2.35
4.7
300mA
1.1
2.2
OUTPUT CURRENT (IMAX)
The typical output capacitance assumes an X7R capacitor with a working voltage high enough such that the fully derated
output capacitance is greater than COUT(MIN).
Thermal Considerations
The MAX25307/MAX25308 are packaged in an 16-pin 3mm x 3mm TQFN package with an exposed pad. The exposed
pad is the main path for heat to leave the IC, and therefore must be connected to a ground plane with thermal vias
to allow heat to dissipate from the device. Thermal properties of the IC package are given in the Package Information
section.
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Maxim Integrated | 13
MAX25307/MAX25308
Two/Three Output Low-Noise LDO Linear
Regulators
Typical Application Circuits
Circuit 1 (MAX25308)
VIN3
VIN2
VIN1
IN3
IN2
IN1
1µF
1µF
4.7µF
10nF
4.7µF
VOUT1
GND
10KΩ
VIO
BYP1
OUT1
BYP2
EN1
EN2
EN3
10KΩ
10nF
OUT2
RESET1
RESET2
RESET3
BYP3
2.2µF
VOUT2
10nF
VOUT3
OUT3
2.2µF
EP
Circuit 2 (MAX25307)
IN2
IN1
VIN2
VIN1
1µF
4.7µF
VIO
10KΩ
BYP1
10nF
OUT1
4.7µF
GND
EN1
EN2
BYP2
OUT2
10KΩ
VOUT1
10nF
VOUT2
2.2µF
RESET1
RESET2
EP
Ordering Information
VOUT1
(V)
IMAX1
(A)
VOUT2
(V)
IMAX2
(A)
VOUT3
(V)
IMAX3
(A)
HOLD
(ms)
MAX25308AATEA/V+
1.2
0.6
1.8
0.3
3.3
0.3
0.5
MAX25307AATEA/V+*
3.3
0.6
1.8
0.3
-
-
3.7
PART NUMBER
*Future product—Contact factory for availability.
+Denotes a lead(Pb)-free/RoHS-compliant package.
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Maxim Integrated | 14
MAX25307/MAX25308
Two/Three Output Low-Noise LDO Linear
Regulators
Revision History
REVISION
NUMBER
REVISION
DATE
0
4/21
DESCRIPTION
Release for market intro
PAGES
CHANGED
—
For pricing, delivery, and ordering information, please visit Maxim Integrated’s online storefront at https://www.maximintegrated.com/en/storefront/storefront.html.
Maxim Integrated cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim Integrated product. No circuit patent
licenses are implied. Maxim Integrated 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.
Maxim Integrated and the Maxim Integrated logo are trademarks of Maxim Integrated Products, Inc.
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