General Description
The MAX8902A/MAX8902B low-noise linear regulators
deliver up to 500mA of output current with only
16µV
RMS
of output noise in a 100kHz bandwidth. These
regulators maintain their output voltage over a wide
input range, requiring only 100mV of input-to-output
headroom at full load.
These LDOs maintain a low 80µA typical supply current, independent of the load current and dropout voltage. The regulator control circuitry includes a
programmable soft-start circuit and short circuit,
reverse current, and thermal-overload protection. Other
features include an enable input and a power-OK output (MAX8902B only).
The MAX8902A output voltage can be set to 1.5V, 1.8V,
2.0V, 2.5V, 3.0V, 3.1V, 3.3V, 4.6V, or 4.7V using the
SELA and SELB inputs. The MAX8902B output voltage
can be set between 0.6V and 5.3V with an external
resistor voltage-divider.
Applications
Notebook Computers
MP3 and Portable Media Players
Wireless Headphones
GPS Portable Navigation Devices
Smartphones
Features
♦ 1.7V to 5.5V Input Voltage Range
♦ 0.6V to 5.3V Output Voltage Range
♦ 16µV
RMS
Output Noise, 10Hz to 100kHz
♦ 80µA Operating Supply Current
♦ 92dB PSRR at 5kHz
♦ Guaranteed 500mA Output Current
♦ ±1.5% Output Accuracy Over Load, Line, and
Temperature
♦ 100mV (max) Dropout at 500mA Load
♦ < 1µA Shutdown Supply Current
♦ 700mA Short-Circuit Protection
♦ Thermal-Overload Protection
♦ Output-to-Input Reverse Current Protection
♦ 2mm x 2mm x 0.8mm TDFN Package
MAX8902A/MAX8902B
Low-Noise 500mA LDO Regulators
in a 2mm x 2mm TDFN Package
________________________________________________________________
Maxim Integrated Products
1
19-0990; Rev 2; 2/08
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.
EVALUATION KIT
AVAILABLE
Ordering Information
IN
EN
OUT
BYP
ON
OFF
OUTPUT
4.6V
SELB
SELA
OUTS
GND
EP
10μF
INPUT
4.7V TO 5.5V
0.01μF
10μF
MAX8902A
Typical Operating Circuits
PART FEATURES
TOP
MARK
PKG
CODE
MAX8902AATA+
Pin-selectable output
voltage
ABG T822-1
MAX8902BATA+
Adjustable output
voltage
ABH T822-1
+
Denotes a lead-free, RoHS-compliant package.
Note: All devices are in an 8-pin, 2mm x 2mm TDFN package
with an exposed paddle and operate over the -40°C to +125°C
automotive temperature range.
IN
EN
OUT
BYP
ON
OFF
OUTPUT ADJUSTABLE
0.6V TO 5.3V
GS
POK
FB
GND
EP
10μF
INPUT
1.7V TO 5.5V
0.01μF
10μF
MAX8902B
R1
R2
LOGIC
SUPPLY
R3
100kΩ
TO μC
Pin Configurations appear at end of data sheet.
MAX8902A/MAX8902B
Low-Noise 500mA LDO Regulators
in a 2mm x 2mm TDFN Package
2 _______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
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.
BYP, EN, IN, OUT, SELA, SELB, POK to GND, GS to GND, FB,
OUTS to GND .....................................................-0.3V to +6.0V
Output Short-Circuit Duration.....................................Continuous
Continuous Power Dissipation (T
A
= +70°C)
8-Pin, 2mm x 2mm TDFN
(derate 11.9mW/°C above +70°C).............................953.5mW
Operating Temperature Range .........................-40°C to +125°C
Junction Temperature Range ............................-40°C to +150°C
Storage Temperature Range .............................-65°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°C
ELECTRICAL CHARACTERISTICS
(VIN= VEN= 5V, OUTS = OUT, circuit of Figure 2 (MAX8902A) and Figure 3 (MAX8902B), TA= -40°C to +125°C, unless otherwise
noted.) (Note 1)
PARAMETER CONDITIONS MIN TYP MAX UNITS
IN
Input Voltage Range 1.7 5.5 V
Input Undervoltage Lockout VIN rising, 100mV typical hysteresis 1.5 1.6 1.7 V
OUT
Output Voltage Range VIN ≥ V
OUT
+ 0.1V 0.6 5.3 V
Output Voltage Accuracy
V
IN
= 1.7V to 5.5V for V
OUT
≤ 1.4V,
V
IN
= (V
OUT
+ 0.3V) to 5.5V for V
OUT
> 1.4V,
I
OUT
= 0.1mA to 500mA
-1.5 +1.5 %
Load Regulation I
OUT
= 0.1mA to 500mA 0.02 %
Line Regulation
V
IN
= 1.7V to 5.5V for V
OUT
≤ 1.4V,
V
IN
= (V
OUT
+ 0.3V) to 5.5V for V
OUT
> 1.4V,
I
OUT
= 200mA
0.04 %
VIN ≥ 3.6V, TA ≤ +85°C 50 100
VIN ≥ 3.6V, TA ≤ +125°C 120
Dropout Voltage
(Note 2)
I
OUT
= 500mA
V
IN
= 1.7V 150
mV
Current Limit V
OUT
= 95% of regulation, VIN = V
OUT
+ 0.5V 600 700 800 mA
Output Noise I
OUT
= 100mA, f = 10Hz to 100kHz, C
BYP
= 0.01µF 16 µV
RMS
f = 5kHz 92
f = 10kHz 85Power-Supply Rejection Ratio I
OUT
= 10mA
f = 100kHz 62
dB
OUTS (MAX8902A only)
OUTS Input Bias Current In regulation 0.5 7.0 µA
FB (MAX8902B only)
FB Threshold Accuracy VIN = 1.7V to 5.5V, I
OUT
= 0.1mA to 500mA 0.591 0.600 0.609 V
TA = +25°C -0.1 0.02 +0.1
FB Input Bias Current VFB = 0.6V
T
A
= -40°C 0.03
µA
BYP
BYP Capacitor Range Regulator remains stable 1 100 nF
BYP Startup Current From BYP to GND during startup 50 µA
MAX8902A/MAX8902B
Low-Noise 500mA LDO Regulators
in a 2mm x 2mm TDFN Package
_______________________________________________________________________________________ 3
ELECTRICAL CHARACTERISTICS (continued)
(VIN= VEN= 5V, OUTS = OUT, circuit of Figure 2 (MAX8902A) and Figure 3 (MAX8902B), TA= -40°C to +125°C, unless otherwise
noted.) (Note 1)
PARAMETER CONDITIONS MIN TYP MAX UNITS
GND
TA < +85°C 80 120
GND Supply Current I
OUT
= 0mA
T
A
< +125°C 160
µA
TA = +25°C 0.001 +1
GND Shutdown Current VIN = 5.5V, EN = 0V
T
A
= +85°C 0.01
µA
SELA/SELB (MAX8902A only)
When shorted to GND or V
IN
500 Ω
Select Input Resistance
When open 1 MΩ
Select Input Capacitance When open 10 pF
EN
EN rising 0.8 1.2
EN falling, TA < +85°C 0.4 0.7Enable Input Threshold VIN = 1.7V to 5.5V
EN falling, T
A
< +125°C 0.38 0.7
V
TA = +25°C -1 0.001 +1
Enable Input Bias Current VEN = 0V to 5.5V
T
A
= +85°C 0.01
µA
POK (MAX8902B only)
OUT rising 88 91 94 %
POK Threshold
OUT voltage when POK
switches
OUT falling 88 %
POK Voltage, Low I
POK
= 1mA 10 100 mV
TA = +25°C -1 0.001 +1
POK Leakage Current POK = 5.5V, VEN = 0V
T
A
= +85°C 0.01
µA
THERMAL SHUTDOWN
TJ rising 165
Thermal Shutdown Threshold
T
J
falling 150
°C
OUTPUT TRANSIENT
Load Transient I
OUT
= 50mA to 500mA to 50mA, t
RISE
= t
FALL
= 1µs 25
mV/
P-P
Line Transient VIN = 4V to 5V to 4V, t
RISE
= t
FALL
= 5µs, I
OUT
= 500mA 3
mV/
P-P
IN-to-OUT Reverse Voltage
Turnoff Threshold
IN falling below OUT 10 mV
Note 1: All devices are production tested at TA= +25°C. Specifications over the operating temperature range are guaranteed by
design and characterization.
Note 2: The dropout voltage is defined V
IN
- V
OUT
, when V
OUT
is 5% lower than the value of V
OUT
when VIN= V
OUT
+ 0.5V.
MAX8902A/MAX8902B
Low-Noise 500mA LDO Regulators
in a 2mm x 2mm TDFN Package
4 _______________________________________________________________________________________
Typical Operating Characteristics
(MAX8902A, VIN= 3.6V, V
OUT
= 2.5V, TA= +25°C, unless otherwise noted.)
0
40
20
80
60
120
100
140
023145
QUIESCENT CURRENT
EN = HIGH, NO LOAD
MAX8902A/02B toc01
INPUT VOLTAGE (V)
INPUT CURRENT (μA)
2.500
2.502
2.501
2.504
2.503
2.505
2.506
0200100 300 400 500
LOAD REGULATION
MAX8902A/02B toc02
LOAD CURRENT (mA)
OUTPUT VOLTAGE (V)
3.6V INPUT
2.490
2.496
2.494
2.492
2.498
2.500
2.502
2.504
2.506
2.508
2.510
1.5 2.5 3.5 4.5 5.5
LINE REGULATION
MAX8902A/02B toc03
INPUT VOLTAGE (V)
OUTPUT VOLTAGE (V)
200mA LOAD
40ms/div
LOAD TRANSIENT RESPONSE
50mA TO 500mA TO 50mA
V
OUT
100mV/div
200mA/div
MAX8902A/02B toc04
I
OUT
t
RISE
= t
FALL
= 1μs
10μs/div
LOAD TRANSIENT RESPONSE
V
IN
2V/div
2mV/div
MAX8902A/02B toc05
V
OUT
2.5V OUTPUT
5Ω LOAD
5V
4V
5V
100μs/div
STARTUP WAVEFORM
V
EN
500mV/div
2V/div
200mA/div
MAX8902A/02B toc06
I
IN
V
OUT
5Ω LOAD
C
BYP
= 0.01μF
0
10
20
30
40
50
60
70
80
0 100 200 300 400 500
DROPOUT VOLTAGE vs. LOAD CURRENT
MAX8902A/02B toc07
LOAD CURRENT (mA)
DROPOUT VOLTAGE (mV)
3.6V INPUT, 4.6V OUTPUT PRESET
THE SLOPE OF THE LINE INDICATES
A 129mΩ ON-RESISTANCE IN
DROPOUT
PSRR vs. FREQUENCY
MAX8902A/02B toc08
10k1k10010 100k
FREQUENCY (Hz)
0
-10
-20
-30
-40
-50
-60
-70
-80
-90
-100
PSRR (dB)
MAX8902A LDO OUTPUT-NOISE SPECTRAL
DENSITY vs. FREQUENCY
MAX8902A/02B toc09
FREQUENCY (Hz)
100k10k1k100
100E+0
1E+3
10E+3
10E+0
10 1M
NOISE DENSITY (nV √Hz)