MAX15101
Small 1A, Low-Dropout Linear Regulator
in a 2.7mm x 1.6mm Package
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Typical Operating Circuit
19-6154; Rev 0; 12/11
Ordering Information appears at end of data sheet.
For related parts and recommended products to use with this part,
refer to www.maxim-ic.com/MAX15101.related.
EVALUATION KIT AVAILABLE
General Description
The MAX15101 is a small, low-dropout linear regulator
optimized for networking, datacom, and server applica-
tions. The regulator delivers up to 1A from a 1.7V to 5.5V
input supply with output accuracy of Q1.6%. The output
is adjustable down to 0.6V with a guaranteed dropout
voltage of less than 100mV at full load. The internal
p-channel switch is protected with a foldback current
limit and thermal shutdown.
The MAX15101 features an external bypass input to
reduce noise. This bypass input also serves as a soft-
start control. An enable input and power-good output are
included for power sequence control.
The MAX15101 is available in a 1.6mm x 2.7mm WLP
package and is fully specified from the -40NC to +85NC
operating temperature range.
Applications
Networking
Telecom/Datacom
Servers
Base Stations
PLL Power
Features
S 1.7V to 5.5V Operating Range
S 100mV Dropout Guaranteed at 1A
S ±1.6% Output Accuracy Over Line, Load, and
Temperature
S Adjustable Output from 0.6V to 5.2V
S Foldback Current Protection
S Thermal Shutdown Protection
S Low Noise 15µVRMS (typ)
S Small 1.6mm x 2.7mm WLP Package
R1
0 TO 4.6kI
R2
600I
OUT
FBPG
EN
IN
COUT
10µF
CIN
2.2µF
INPUT
(1.7V TO 5.5V)
POWER-GOOD
OUTPUT
CSS
100nF
SS_BYPGND
OUTPUT
(0.6V TO VIN - 200mV)
MAX15101
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.
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MAX15101
Small 1A, Low-Dropout Linear Regulator
in a 2.7mm x 1.6mm Package
IN, EN, PG, SS_BYP, FB to GND ...........................-0.3V to +6V
OUT to GND ............................................... -0.3V to (VIN + 0.3V)
OUT Short Circuit ......................................................Continuous
Continuous Power Dissipation (TA = +70NC)
WLP (derate 19.2mW/NC above +70NC) ....................1538mW
Operating Temperature Range ........................ -40NC to +85NC
Storage Temperature Range ......................... -65NC to +150NC
Junction Temperature ....................................................+150NC
Soldering Temperature (reflow) (Note 1) ........................+260NC
WLP
Junction-to-Ambient Thermal Resistance (qJA) ..........30°C/W
ABSOLUTE MAXIMUM RATINGS
Note 2: 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.maxim-ic.com/thermal-tutorial.
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional opera-
tion 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 2)
ELECTRICAL CHARACTERISTICS
(VIN = 3.3V, VOUT = 1.5V, VEN = VIN, IOUT = 100mA, CIN = 2.2µF, COUT = 22µF, TA = TJ = -40NC to +85NC, typical values are at
TA = +25NC, unless otherwise noted.) (Note 3)
Note 1: The WLP package is constructed using a unique set of package techniques that impose a limit on the thermal profile. The
device can be exposed during board-level solder attach and rework. This limit permits only the use of the solder profiles
recommended in the industry-standard specification JEDEC 020A, paragraph 7.6, Table 3 for IR/VPR and convection
reflow. Preheating is required. Hand or wave soldering is not allowed.
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
IN
Input Voltage Range VIN 1.7 5.5 V
Input Undervoltage Lockout VIN_UV VIN rising 1.624 1.69 V
Input Undervoltage Lockout
Hysteresis VIN_UV_HYS 40 mV
OUT
Output Voltage Range VOUT 0.6 5.2 V
Load Regulation IOUT = 30mA to 1A 0.1 %/A
Line Regulation VIN = 1.7V to 5.5V, VOUT = 0.6V,
IOUT = 190mA -0.15 +0.15 %/V
Dropout Voltage IOUT = 1A, VFB = 580mV (Note 4) 25 100 mV
In-Regulation Current Limit VIN = 5.5V, VFB = 500mV 1.62 A
Short-Circuit Foldback Current
Limit VIN = 5.5V, VOUT = 0V, VFB < 100mV 1 A
Output Shutdown Leakage VIN = 5.5V, VOUT = 0V, VEN = 0V 4 FA
Line Transient DVIN = 0.5V, tRISE = tFALL = 5Fs2 %
����������������������������������������������������������������� Maxim Integrated Products 3
MAX15101
Small 1A, Low-Dropout Linear Regulator
in a 2.7mm x 1.6mm Package
Note 3: All devices 100% production tested at TA = +25°C. Limits over the temperature range are guaranteed by design.
Note 4: Dropout is defined as VIN - VOUT when VOUT falls 3% below its nominal voltage value.
ELECTRICAL CHARACTERISTICS (continued)
(VIN = 3.3V, VOUT = 1.5V, VEN = VIN, IOUT = 100mA, CIN = 2.2µF, COUT = 22µF, TA = TJ = -40NC to +85NC, typical values are at
TA = +25NC, unless otherwise noted.) (Note 3)
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
Load Transient IOUT = 100mA to 1A to 100mA,
tRISE = tFALL = 1Fs1.3 %
Power-Supply Rejection Frequency = 100kHz, IOUT = 500mA 40 dB
Output Voltage Noise Frequency = 500Hz to 100kHz,
IOUT = 100mA 15 FVRMS
FB
FB Threshold Accuracy
IOUT = 190mA, VOUT = 1.5V to 5V,
VIN = (VOUT + 0.3V) to 5.5V 593 600 606
mV
IOUT = 3mA to 1A, VOUT = 1.5V to 5V,
VIN = (VOUT + 0.3V) to 5.5V 590 610
FB Input Current VFB = 0.6V, VIN = 5.5V 1 FA
GND
Ground Supply Current 1.8 3.5 mA
Ground Shutdown Current VIN = 1.7V to 5.5V 1 FA
POWER-GOOD OUTPUT
Power-Good (PG) Threshold VFB moving out of
regulation, VHYS = 15mV
FB = high 638 650 662 mV
FB = low 538 550 562
Power-Good (PG) Output-
Voltage Low IPG = 2mA (sink) 25 80 mV
Power-Good (PG) Delay 100 Fs
Power-Good (PG) Leakage VPG = 5.5V 1 FA
ENABLE
Enable Input High Threshold VEN_HIGH 1.2 V
Enable Input Low Threshold VEN_LOW 0.4 V
Enable Input Bias Current VEN = 0 to 5.5V -1 +1 FA
SOFT-START
Soft-Start Charging Current VSS_BYP = 100mV 8 9.2 12 FA
Soft-Start Pulldown Resistance VEN = 0V, ISS_BYP = 2mA 45 100 I
THERMAL SHUTDOWN
Thermal Shutdown Threshold +160 NC
Thermal Shutdown Hysteresis Threshold falling 15 NC
����������������������������������������������������������������� Maxim Integrated Products 4
MAX15101
Small 1A, Low-Dropout Linear Regulator
in a 2.7mm x 1.6mm Package
Typical Operating Characteristics
(VIN = 1.8V, VOUT = 1.5V, TA = +25NC, unless otherwise noted.)
0.80.60.40.2
10
20
30
DROPOUT VOLTAGE
vs. OUTPUT CURRENT
MAX15101 toc01
OUTPUT CURRENT (A)
DROPOUT VOLTAGE (mV)
40
0
0 1.0
VOUT = 2.5V
VOUT = 1.8V
VOUT = 5V
DEFINED VIN - VOUT WHEN VOUT FALLS 2%
BELOW NOMINAL
VOUT = 3.3V
OUTPUT VOLTAGE
vs. TEMPERATURE
MAX15101 toc04
TEMPERATURE (°C)
OUTPUT VOLTAGE (V)
603510-15
1.484
1.486
1.488
1.490
1.492
1A LOAD
1.494
1.496
1.498
1.482
-40 85
NO LOAD
SOFT-START TIME
vs. CAPACITOR VALUE
MAX15101 toc06
CAPACITOR VALUE (nF)
SOFT-START TIME (ms)
85654525
1
2
3
4
5
6
7
8
9
10
0
5 100
STARTUP WAVEFORMS
MAX15101 toc05
CSS =100nF
VEN
1V/div
IIN
2A/div
VOUT
1V/div
VPG
1V/div
1ms/div
FB VOLTAGE vs. TEMPERATURE
(VOUT = 1.5V)
MAX15101 toc07
TEMPERATURE (°C)
FB VOLTAGE (V)
603510-15
0.592
0.593
0.594
0.595
0.596
0.597
0.598
0.599
0.600
0.591
-40 85
NO LOAD
1A LOAD
0.80.60.40.2
OUTPUT VOLTAGE ERROR
vs. OUTPUT CURRENT
MAX15101 toc02
OUTPUT CURRENT (A)
OUTPUT VOLTAGE ERROR (%)
-0.05
0
0.05
0.10
-0.10
0 1.0
VOUT = 3V
VOUT = 2.5V
VOUT = 1.5V
OUTPUT VOLTAGE
vs. INPUT VOLTAGE
MAX15101 toc03
INPUT VOLTAGE (V)
OUTPUT VOLTAGE (V)
4.84.33.83.32.82.3
1.490
1.495
1.500
1.505
1.510
1.515
IOUT = 0.5A
1.485
1.8 5.3
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MAX15101
Small 1A, Low-Dropout Linear Regulator
in a 2.7mm x 1.6mm Package
Typical Operating Characteristics (continued)
(VIN = 1.8V, VOUT = 1.5V, TA = +25NC, unless otherwise noted.)
SHORT-CIRCUIT WAVEFORMS
MAX15101 toc12
IOUT
2A/div
VPG
1V/div
VOUT
1V/div
VIN
2V/div
200µs/div
1.8V
1A LOAD-TRANSIENT RESPONSE
(COUT = 10µF)
MAX15101 toc08
IOUT
500mA/div
VOUT
AC-COUPLED
50mV/div
100mA
1A
40µs/div
FOLDBACK CURRENT-LIMIT
WAVEFORMS
MAX15101 toc10
IOUT
2A/div
VOUT
500mV/div
100µs/div
GROUND CURRENT
vs. INPUT VOLTAGE
MAX15101 toc11
INPUT VOLTAGE (V)
GROUND CURRENT (mA)
5.04.54.03.53.02.52.01.51.00.5
0.5
1.0
1.5
2.0 ILOAD = 1A
ILOAD = 0A
2.5
3.0
0
05
.5
PSRR vs. FREQUENCY
(ILOAD = 0.5A)
MAX15101 toc13
90
80
70
60
50
40
30
20
10
10Hz 1MHz100kHz
FREQUENCY
PSRR (dB)
LINE-TRANSIENT RESPONSE
MAX15101 toc09
VOUT
AC-COUPLED
20mV/div
VIN
200mV/div
1.8V
2.3V
ILOAD = 1A
100µs/div
NOISE DENSITY
(ILOAD = 100mA)
MAX15101 toc14
FREQUENCY (Hz)
NOISE DENSITY (µVRMS)
10k1k
6
9
12
15
18
3
100 100k
NO CSS
CSS = 4.7nF
CSS = 100nF
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MAX15101
Small 1A, Low-Dropout Linear Regulator
in a 2.7mm x 1.6mm Package
Bump Description
Bump Configuration
BUMP NAME FUNCTION
A1 EN Active-High Enable Input. Drive EN logic-high to enable the LDO. Connect to IN for always-on
operation.
A2 PG Power-Good Output. Open-drain output asserts high when the voltage is within regulation.
A3 GND Ground
A4 SS_BYP SS_BYP Bypass/Soft-Start Input. Connect a ceramic capacitor from SS_BYP to GND to reduce the
output noise and set the soft-start ramp time.
A5 FB Feedback Input. Connect a resistive divider from OUT to GND to set the output voltage.
B1, B2, B3,
B4, B5 IN Supply Voltage Input. Connect to supply voltage from 1.7V to 5.5V. Bypass IN to GND with a 2.2FF
or greater ceramic capacitor.
C1, C2, C3,
C4, C5 OUT Regulated Output. Connect a 10FF capacitor from OUT to GND. For better load transient
performance a larger capacitor can be used.
WLP
TOP VIEW
OUTOUT
ININ
SS_BYPEN
MAX15101
+
12 345
A
OUT OUT
IN IN
PG GND
B
C
OUT
IN
FB
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MAX15101
Small 1A, Low-Dropout Linear Regulator
in a 2.7mm x 1.6mm Package
Functional Diagram
Detailed Description
The MAX15101 is a small, low-dropout linear regulator
optimized for server, network, and telecom applications.
The regulator delivers up to 1A from a 1.7V to 5.5V input
supply with output accuracy of Q1.6%. The output is
adjustable down to 0.6V with a guaranteed dropout volt-
age of less than 100mV at full load. The internal p-chan-
nel switch is protected with a foldback current limit and
thermal shutdown.
The MAX15101 features an external bypass input to
reduce noise. This bypass input also serves as a soft-
start control. An enable input and power-good output are
included for power sequence control.
Internal p-Channel Pass Transistor
The MAX15101 features a 1A p-channel MOSFET pass
transistor. Unlike similar designs with pnp pass transistors,
the gate-drive current to the p-channel power transistor is
extremely low. PNP-based regulators also waste consider-
able current in dropout when the pass transistor saturates
and uses high base-drive currents under large loads. The
MAX15101 does not suffer from these deficiencies and
consumes only 1.8mA of quiescent current even in dropout.
Output Voltage Selection
The MAX15101 features an adjustable output. The out-
put voltage can be set between +0.6V to VIN - 200mV
using an external resistive voltage-divider to FB (see
the Typical Operating Circuit). The output voltage is set
using the following equation:
VOUT = VFB (1 + R1/R2)
where VFB = +600mV.
To simplify resistor selection:
R1 = R2 (VOUT/VFB - 1)
Set R2 to 600I.
THERMAL-
OVERLOAD
PROTECTION
SHUTDOWN
LOGIC
PG
CIRCUITRY
UNDERVOLTAGE
LOCKOUT
ERROR
AMPLIFIER
ILIM
OUT
FB
PG
REF
EN
IN
0.60V
SS_BYP
0.55V
0.65V
gM
P
N
GND
MAX15101
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MAX15101
Small 1A, Low-Dropout Linear Regulator
in a 2.7mm x 1.6mm Package
Enable
A logic-low on EN disables the MAX15101. In shutdown,
the pass transistor, control circuitry, reference, and all
biases are turned off, reducing supply current to typically
1FA. Connect EN to IN for normal operation. In shutdown,
the soft-start capacitor is discharged using an internal
pulldown resistance.
Soft-Start
As shown in the Typical Operating Circuit, the MAX15101
uses a gM stage and integrating capacitor CSS to control
the regulator’s feedback set point. When EN is driven
low, the soft-start capacitor is discharged. When EN is
driven high or power is applied to the device, a constant
9.2FA current charges the soft-start capacitor. At startup,
the feedback set point increases linearly, which reduces
the inrush supply current.
tSS = 6.315 x 10-5 x CSS
where CSS is in nF. Use capacitor values between 30nF
to 100nF with voltage ratings greater than 5V.
Because this ramp is applied to the current-limit com-
parator, the actual time for the output voltage to ramp up
depends on the load current and output capacitor. Leave
SS_BYP unconnected to disable soft-start.
Foldback Current Limiting
The MAX15101 features a 1.6A current limit when the
output voltage is in regulation. When the voltage at the
output drops to 17% of its nominal value, the current
limit exponentially folds back to 1A. The output can be
shorted to ground for an indefinite period of time without
damaging the device. Avoid continuous output current of
greater than 1A to prevent damage to the regulator.
Thermal-Overload Protection
A thermal-overload circuit limits total power dissipation in
the MAX15101. When the junction temperature exceeds
TJ = +160NC, the thermal sensor turns off the pass tran-
sistor, allowing the IC to cool. The thermal sensor turns
the pass transistor on once the IC’s junction temperature
drops approximately 15NC. Continuous short-circuit condi-
tions will consequently result in a foldback limited output.
Thermal-overload protection is designed to safeguard
the MAX15101 in the event of fault conditions. For contin-
uous operation, do not exceed the junction temperature
rating of TJ = +125NC.
Operating Region and Power Dissipation
The power dissipation across the device is P = IOUT
(VIN - VOUT). The resulting maximum power dissipation is:
PMAX = [(TJ(MAX) - TA)/(BJA)]
where (TJ(MAX) - TA) is the temperature difference
between the maximum allowed die junction (+150NC) and
the surrounding air. Figure 1 shows the allowable power
dissipation for typical PCBs at +25NC, +50NC, and +70NC
ambient temperatures (refer to the MAX15101 EV kit).
Applications Information
Capacitor Selection and Regulator Stability
Capacitors are required at the MAX15101’s input and
output. Connect at least a 2.2FF capacitor between IN
and GND (CIN) and a 10FF capacitor between OUT and
GND (COUT). Use only surface-mount ceramic capaci-
tors that have low equivalent series resistance (ESR).
Make the input and output traces at least 2.5mm wide,
and connect CIN and COUT within 6mm of the IC to mini-
mize the impact of PCB trace inductance.
The output capacitor’s ESR can affect stability and output
noise. Use capacitors with 50mI or less ESR to ensure
stability and optimum transient response. This is par-
ticularly true in applications with very low output voltage
(< 2V) and high output current (> 0.5A).
Since some capacitor dielectrics can vary over bias volt-
age and temperature, consult the capacitor manufacturer
specifications to ensure that the capacitors meet these
requirements over all combinations of operating voltage
and temperature.
Figure 1. Maximum Output Current Curves
0.25
0.50
0.75
1.00
INPUT-OUTPUT DIFFERENTIAL VOLTAGE (V)
MAXIMUM OUTPUT CURRENT (A)
4321
1.25
0
05
TJ = +125NC (BASED ON MAX15101 EV KIT)
MAXIMUM CONTINUOUS CURRENT
TA = +70NC
TA = +50NC
TA = +25NC
����������������������������������������������������������������� Maxim Integrated Products 9
MAX15101
Small 1A, Low-Dropout Linear Regulator
in a 2.7mm x 1.6mm Package
Input-Output (Dropout) Voltage
A regulator’s minimum input-to-output voltage differential
(dropout voltage) determines the lowest usable supply
voltage. The dropout voltage is simply the product of
regulator’s RDS(ON) for the pass device and rated load
current. The MAX15101‘s RDS(ON) is 20mI, at 1A this
yields a dropout voltage of 20mV (see the Electrical
Characteristics and the Dropout Voltage vs. Output
Current graph in the Typical Operating Characteristics).
Noise, PSRR, and Transient Response
The MAX15101 is designed to achieve low dropout
voltage while still maintaining good noise, transient
response, and AC rejection. When operating from very
noisy sources, supply noise rejection and transient
response can be improved by increasing the values of
the input and output capacitors. The MAX15101 output
noise is typically 15FVRMS (see the Noise Density graph
in the Typical Operating Characteristics).
Thermal Considerations
in PCB Layout
The rated package dissipation strongly depends on the
copper area connected to the regulator. The maximum
power dissipation allowed in the package is 1538mW
(measured from the MAX15101 EV kit).
More power dissipation can be handled by the package
if great attention is given during PCB layout. For example,
using the top and bottom copper as a heatsink and
connecting the thermal vias to one of the middle layers
(GND) transfers the heat from the package into the board
more efficiently, resulting in lower junction temperature at
high power dissipation in some MAX15101 applications.
Furthermore, the solder mask around the IC area on both
top and bottom layers can be removed to radiate the heat
directly into the air. The maximum allowable power dis-
sipation in the IC is as follows:
PMAX = [(TJ(MAX) - TA)/(BJA)]
where (TJ(MAX) - TA) is the temperature difference
between the maximum-allowed die junction (+150NC)
and the surrounding air.
A sample layout is available on the MAX15101 EV kit.
+Denotes a lead(Pb)-free/RoHS-compliant package.
Ordering Information
Chip Information
PROCESS: BiCMOS
Package Information
For the latest package outline information and land patterns
(footprints), go to www.maxim-ic.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.
PART TEMP RANGE PIN-PACKAGE
MAX15101EWL+ -40NC to +85NC15 WLP
PACKAGE
TYPE
PACKAGE
CODE
OUTLINE
NO.
LAND
PATTERN NO.
15 WLP W151B2+1 21-0205
Refer to
Application
Note 1891
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied.
Maxim 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 Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 10
© 2011 Maxim Integrated Products Maxim is a registered trademark of Maxim Integrated Products, Inc.
MAX15101
Small 1A, Low-Dropout Linear Regulator
in a 2.7mm x 1.6mm Package
Revision History
REVISION
NUMBER
REVISION
DATE DESCRIPTION PAGES
CHANGED
0 12/11 Initial release —
