Rainbow Electronics MAX15028 User Manual
General Description
The MAX15027/MAX15028 low-dropout linear regulators
operate from input voltages as low as 1.425V and deliver
up to 1A of continuous output current with a typical
dropout voltage of only 75mV. The output voltage is
adjustable from 0.5V to V
IN
and is ±2% accurate over load
and line variations, from -40°C to +125°C. The MAX15028
features a BIAS input of 3V to 5.5V from an always-on
power supply. The BIAS input current is reduced down to
less than 2µA during shutdown.
These regulators use small, 1µF ceramic input capacitors and 4.7µF ceramic output capacitors to deliver 1A
output current. High bandwidth provides excellent transient response and limits the output voltage deviation to
15mV for a 500mA load step, with only a 4.7µF ceramic
output capacitor, and the voltage deviations can be
reduced further by increasing the output capacitor.
These devices offer a logic-controlled shutdown input
to reduce input current (IIN) consumption down to less
than 5.5µA in standby mode. Other features include a
soft-start to reduce inrush current, short-circuit protection, and thermal-overload protection.
The MAX15028 features a BIAS input allowing a secondary supply to keep the LDO’s internal circuitry alive
if the voltage on IN goes to 0V. Both devices are fully
specified from -40°C to +125°C and are available in a
10-pin thermally enhanced TDFN package (3mm x
3mm) that includes an exposed pad for optimal power
dissipation. For a 500mA version of these LDOs, refer
to the MAX15029/MAX15030 data sheet.
Applications
Automotive (Dead-Man LDO)
Servers
Storage
Networking
Base Stations
Optical Modules
ATE
Features
o 1.425V to 3.6V Input Voltage Range
o Output Voltage Programmable from 0.5V to V
IN
o Guaranteed Maximum 225mV Dropout at 1A
Output Current
o ±2% Output Accuracy Over Load, Line, and
Temperature
o Stable with Ceramic Capacitors
o Fast Transient Response
o 60µA Operating Bias Supply Current (MAX15028)
o 1.2µA Shutdown Bias Supply Current (MAX15028)
o Short-Circuit and Thermal Protection
o -40°C to +125°C Operating Temperature Range
o Soft-Start Limits Inrush Current
o Thermally Enhanced 3mm x 3mm TDFN Package
MAX15027/MAX15028
1.425V to 3.6V Input, 1A Low-Dropout
Regulators with BIAS Input
________________________________________________________________
Maxim Integrated Products
1
Pin Configurations
Ordering Information
19-4488; Rev 0; 3/09
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.
Pin Configurations continued at end of data sheet.
PART
TEMP RANGE
PINPACKAGE
TOP
MARK
MAX15027ATB+T
+AUD
MAX15028ATB+T
+AUE
+
Denotes a lead(Pb)-free and RoHS-compliant package.
For tape-and-reel orders, add a “T” after the “+”.
*
EP = Exposed pad.
Typical Operating Circuits appear at end of data sheet.
- 40°C to + 125°C 10 TDFN-EP*
- 40°C to + 125°C 10 TDFN-EP*
TOP VIEW
+
IN
1
29
IN
3
I.C.
4
56
MAX15027
TDFN
(3mm x 3mm)
10
8
7
OUT
OUTIN
GND
FB
SSEN
MAX15027/MAX15028
1.425V to 3.6V Input, 1A Low-Dropout
Regulators with BIAS Input
2 _______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS
(Circuit of Figure 1; VIN= 1.8V, V
OUT
= 1.2V, EN = IN for MAX15027, EN = BIAS for MAX15028, I
OUT
= 100mA, T
A
= T
J
= -40°C to
+125°C. Typical values are at T
A
= +25°C, unless otherwise noted.) (Note 2)
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.
IN, FB, SS, I.C. to GND..........................................-0.3V to +4.0V
BIAS to GND.............................................................-0.3V to +6V
EN to GND ................-0.3V to the lower of (V
BIAS
+ 0.3V) or +6V
OUT to GND ................................................-0.3V to (V
IN
+ 0.3V)
Output Short-Circuit Duration.....................................Continuous
Continuous Power Dissipation (T
A
= +70°C)
10-Pin TDFN, Multilayer Board
(derate 24.4mW/°C above +70°C)..............................1951mW
Junction-to-Case Thermal Resistance, θ
JC
.......................9°C/W
Junction-to-Ambient Thermal Resistance, θ
JA
(Note 1)...41°C/W
Operating Junction Temperature Range...........-40°C to +125°C
Maximum Junction Temperature .....................................+150°C
Storage Temperature Range .............................-65°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°C
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.maxim-ic.com/thermal-tutorial
.
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
IN
Input Voltage Range V
Undervoltage Lockout V
Undervoltage Lockout Hysteresis V
Quiescent GND Current I
Input Supply Current in Shutdown I
BIAS (MAX15028)
Input Voltage Range V
Undervoltage Lockout V
Undervoltage Lockout Hysteresis I
Quiescent Input Supply Current I
Input Supply Current in Shutdown I
MAX15027 1.425 3.600
V
IN
UVLO
UVLO_HYST
MAX15028
VIN rising,
I
OUT
VIN = 1.425V to 3.6V, V
I
GND
OUT
VIN = 3.6V, V
VIN = 3.3V, V
IN_SD
BIAS
BIAS_UVLOVBIAS
BIAS
BIAS_SD
VEN = 0, TA = - 40°C to + 85°C 0.1 5.5 µA
OUT
VEN = V
EN = GND
= 2mA
= 1mA, V
rising, I
BIAS
= 3.3V, I
OUT
= 3.3V, I
OUT
= 2mA 2.3 2.5 2.7 V
OUT
= 2mA 110 mV
BIAS
= 3V to 5.5V 1.425 3.600
BIAS
BIAS = IN 3.000 3.600
MAX15027 1.275 1.325 1.375
MAX15028 1.04 1.106 1.14
= 1.2V,
OUT
= 3.3V
= 100mA 180 275 560
OUT
= 500mA 170 315 470
OUT
VIN = 0, V
V
BIAS
V
I N
V
B I AS
V
I N
V
B I AS
OUT
= 3.3V
= 3.3V , V
= 3.3V
= 3.3V , V
= 5V
= 0,
OU T
OU T
= 0,
= 0,
160 275 410
3 5.5 V
20 60 120 µA
50 mV
1.2 2
1.2 2
1.5 3
V
V
µA
µA
MAX15027/MAX15028
1.425V to 3.6V Input, 1A Low-Dropout
Regulators with BIAS Input
_______________________________________________________________________________________ 3
ELECTRICAL CHARACTERISTICS (continued)
(Circuit of Figure 1; VIN= 1.8V, V
OUT
= 1.2V, EN = IN for MAX15027, EN = BIAS for MAX15028, I
OUT
= 100mA, T
A
= T
J
= -40°C to
+125°C. Typical values are at T
A
= +25°C, unless otherwise noted.) (Note 2)
Note 2: All devices are 100% production tested at T
A
= +25°C. Limits over the operating temperature range are guaranteed by
design and characterization.
OUT
Output Voltage Range V
Load Regulation I
Line Regulation VIN = 1.425V to 3.6V, I
Dropout Voltage (VIN - V
Output Current Limit I
FB
Threshold Accuracy V
Input Current I
EN/SOFT-START
Enable Input Threshold
(MAX15028)
Enable Input Threshold
(MAX15027)
Soft-Start Charging Current I
Soft-Start Reference Voltage V
THERMAL SHUTDOWN
Thermal-Shutdown Threshold TJ rising 165 °C
Thermal-Shutdown Hysteresis 15 °C
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
)VDOI
OUT
OUT
= 1mA to 1A 0.01 mV/mA
OUT
= 1mA 4 mV
OUT
= 1A, VIN = 1.5V 75 225 mV
OUT
LIM
V
V
V
V
FB
FB
IH
IL
IH
IL
SS
SS
VFB = 300mV 1.4 1.7 2.0 A
V
= 0.5V to 3.3V, VIN = (V
OUT
to 3.6V, I
VFB = 0.688V 0.1 0.2 µA
V
BIAS
VIN = 1.8V
OUT
= 5V
= 1mA to 1A
OUT
+ 0.3V)
0.5 3.3 V
0.489 0.499 0.509 mV
1.05
1.05
5µA
0.499 V
0.4
0.4
V
V
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