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19-4092; Rev 0; 5/08
EVALUATION KIT
AVAILABLE
1A, 97% Efficiency, 30µA Quiescent Current
Step-Up Converter with True Shutdown
www.datasheet4u.com
General Description
The MAX8815A DC-DC step-up converter is a high-effi-
ciency, low quiescent current, synchronous step-up
converter with True Shutdown™ and inrush-current lim-
iting. The MAX8815A generates any output voltage
from 3.3V to 5V from a 2-cell NiMH/NiCd or a single-cell
Li+/Li polymer battery.
The MAX8815A uses two modes of operation. The first
mode of operation (normal) uses only 30µA (typ) quies-
cent current and allows the converter to switch only
when needed at no load and light loads. Under moder-
ate and heavy loads (typically above 90mA), the
MAX8815A uses a fixed-frequency pulse-width modula-
tion (PWM) technique. This mode allows maximum effi-
ciency at light loads. The second mode of operation is
a fixed-frequency forced-pulse-width modulation
(FPWM) mode where the converter switches at a fixed
frequency irrespective of the load. This mode allows for
easy noise filtering and lower output ripple.
The MAX8815A has a preset 2.5A current limit, allowing
500mA load at 1.8V input and 1A load at 2.5V input when
the output is set to 5V. Features include soft-start, which
limits inrush current during startup, True Shutdown, and
internal compensation. The MAX8815A is available in a
compact 10-pin, 3mm x 3mm TDFN package.
The MAX8815A evaluation kit can help shorten the time
required for system design.
Applications
DSC and DVC
Microprocessor/DSP Core Power
Cell Phones, PDAs, MP3 Players
Portable Handheld Devices
PCMCIA Cards
True Shutdown is a trademark of Maxim Integrated Products, Inc.
Pin Configuration
TOP VIEW
10 9 8 7 6
MAX8815A
+
1 2345
Features
Up to 97% Efficiency with Internal Synchronous
Rectifier
Low 30µA Quiescent Current
Guaranteed 500mA Output Current at VOUT = 5V
from 1.8V Input
Guaranteed 1A Output Current at 5V from 2.5V
Input
Low-Noise Constant Frequency Operation (FPWM
Mode)
2MHz PWM Switching Frequency
Preset (5V) or Adjustable Output
Controlled Current in Soft-Start Limits Inrush
Current
True Shutdown
Internal Compensation
Overload/Short-Circuit Protection
0.1µA Shutdown Current
Thermal Shutdown
Compact 10-Pin, 3mm x 3mm TDFN Package
Ordering Information
PART
PIN-PACKAGE
TOP MARK
MAX8815AETB+
10 TDFN-EP*
AUH
+Denotes a lead-free package.
*EP = Exposed pad.
Note: This device operates in the -40°C to +85°C extended
operating temperature range.
Typical Operating Circuit
INPUT VOLTAGE
1.2V TO 5.5V
BATT LX
ON POUT
MAX8815A OUTS
FB
SKIPB
GND
OUTPUT VOLTAGE
5V UP TO 1A
________________________________________________________________ Maxim Integrated Products 1
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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1A, 97% Efficiency, 30µA Quiescent Current
Step-Up Converter with True Shutdown
www.daAtasBheSetO4uL.cUomTE MAXIMUM RATINGS
OUTS, BATT to GND ................................................-0.3V to +6V
POUT to OUTS ......................................................-0.3V to +0.3V
PGND (EP) to AGND .............................................-0.3V to +0.3V
FB to GND ................................................-0.3V to (VOUT + 0.3V)
ON, SKIPB to GND ............-0.3V to the higher of (VOUTS + 0.3V)
and (VBATT + 0.3V)
LX Continuous Current (Note 1)..........................................2.75A
Continuous Power Dissipation (TA = +70°C)
10-Pin TDFN Single-Layer Board (derate 18.5 mW/°C
above +70°C)...........................................................1481.5mW
10-Pin TDFN Multilayer Board (derate 24.4 mW/°C
above +70°C)...........................................................1951.2mW
Junction-to-Case Thermal Resistance (θJC) (Note 2)
10-Pin TDFN .................................................................8.5°C/W
Junction-to-Ambient Thermal Resistance (θJA) (Note 2)
10-Pin TDFN ..................................................................41°C/W
Operating Temperature Range ...........................-40°C to +85°C
Junction Temperature Range ............................-40°C to +150°C
Storage Temperature Range .............................-65°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°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.
Note 1: LX has internal clamp diodes to PGND (EP) and VPWR, where VPWR is the internal power node and is the higher of BATT
and OUTS. Applications that forward bias these diodes should take care not to exceed the power-dissipation limits of the
device.
Note 2: Package thermal resistances were obtained using the method described in JEDEC specification JESD51-7, using a 4-layer
board. For detailed information on package thermal considerations, visit www.maxim-ic.com/thermal-tutorial.
ELECTRICAL CHARACTERISTICS
(VOUTS = VPOUT = 5V, VON = VBATT = 3.6V, VSKIPB = GND, TA = -40°C to +85°C, typical values are at TA = +25°C, unless otherwise
noted. Limits are 100% production tested at TA = +25°C. Limits over the operating temperature range are guaranteed by design and
characterization.)
PARAMETER
GENERAL
Operating Input Voltage Range
Minimum Startup Voltage
Shutdown Supply Current
Supply Current
OSCILLATOR
Switching Frequency
Maximum Duty Cycle
Output-Voltage Adjust Range
FB Regulation Voltage
FB Load Regulation
FB Line Regulation
FB Input Leakage Current
Idle Mode™ Trip Level
CONDITIONS
ON = GND
TA = +25°C
TA = +85°C
No load, no switching, VFB = 1.28V
No load, switching (measured with external feedback);
VPOUT = 5V
No load, TA = +25°C
No load, TA = -40°C to +85°C (Note 3)
VBATT = 1.8V to 5V, IPOUT = 0.5A
VFB = 1.28V, VOUTS =
VPOUT = VBATT = 5.5V
TA =+25°C
TA = +85°C
(Note 4)
MIN TYP MAX UNITS
1.2 5.5
1.2 1.5
0.1 1
0.2
16 30
30
V
V
µA
µA
1.8
3.3
1.255
1.252
-50
2.0
87.5
1.265
1.265
-7.5
-10
-5
-5
90
2.2
5.0
1.275
1.277
+50
MHz
%
V
V
mV/A
mV/D
nA
mA
Idle Mode is a trademark of Maxim Integrated Products, Inc.
2 _______________________________________________________________________________________

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1A, 97% Efficiency, 30µA Quiescent Current
Step-Up Converter with True Shutdown
www.daEtaLshEeeCt4Tu.RcomICAL CHARACTERISTICS (continued)
(VOUTS = VPOUT = 5V, VON = VBATT = 3.6V, VSKIPB = GND, TA = -40°C to +85°C, typical values are at TA = +25°C, unless otherwise
noted. Limits are 100% production tested at TA = +25°C. Limits over the operating temperature range are guaranteed by design and
characterization.)
PARAMETER
CONDITIONS
MIN TYP MAX UNITS
DC-DC SWITCHES
p-Channel On-Resistance
0.14 0.25
Ω
n-Channel On-Resistance
0.1 0.17
Ω
n-Channel Current Limit
2.20 2.5 2.75
A
p-Channel Turn-Off Current
10 mA
OUT Leakage Current
LX Leakage Current
Soft-Start Interval
VLX = VON = 0V, VOUTS =
VPOUT = VBATT = 5.5V
VLX = 0V or 5.5V, VOUTS =
VPOUT = VBATT = 5.5V,
VON = 0V
Load dependent
TA = +25°C
TA = +85°C
TA = +25°C
TA = +85°C
0.1 2
0.2
0.1 2
0.2
6
µA
µA
ms
Overload Protection Fault Delay
16 ms
Startup into a Short Circuit
6 ms
LOGIC INPUTS
ON Input Low Level
ON Input High Level
SKIPB Input Low Level
SKIPB Input High Level
ON, SKIPB Input Leakage
Current
Thermal Shutdown
VOUTS = VPOUT = 0V and 1.5V < VBATT < 5.5V
VOUTS = VPOUT = 0V and 1.5V < VBATT < 5.5V, VH is the
highter of VPOUT and VBATT
3.3V < VPOUT < VOUT < 5.5V
3.3V < VPOUT < VOUT < 5.5V
VOUTS = VPOUT = VBATT = TA = +25°C
5.5V
TA = +85°C
VH -
0.2V
(1.3V
max)
1.6
0.01
0.02
+167
0.5
0.5
1
V
V
V
V
µA
°C
Note 3: Guaranteed by design. Not production tested.
Note 4: The idle-mode current threshold is the transition point between fixed-frequency PWM operation and idle-mode operation. The
specification is given in terms of output load current for inductor values shown in the typical application circuits (Figure 1). The
idle-mode transition varies with input-to-output voltage ratio.
_______________________________________________________________________________________ 3

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1A, 97% Efficiency, 30µA Quiescent Current
Step-Up Converter with True Shutdown
www.datasheet4u.com
(VOUTS = VPOUT = 5V, VBATT = VON = 3.6V, VSKIPB = GND.)
Typical Operating Characteristics
EFFICIENCY vs. LOAD
CURRENT, VOUT = 3.3V
100
VIN = 1.8V, SKIP
90 = 1.5V, SKIP
80
70
60
50
VIN = 3V, SKIP
40 = 2.5V, SKIP
30 = 3V, FPWM
20
10
0
0.1
VIN = 2.5V, SKIP
= 1.8V, SKIP
= 1.5V, FPWM
1 10 100
OUTPUT CURRENT (mA)
1000
MAXIMUM LOAD CURRENT
vs. INPUT VOLTAGE
1.4
1.2 VOUT = 3.3V
1.0
0.8
VOUT = 5V
0.6
0.4
0.2
0
1.2 1.7 2.2 2.7 3.2 3.7
INPUT VOLTAGE (V)
OUTPUT VOLTAGE
vs. LOAD CURRENT
3.38
FPWM
3.36 SKIP
3.34
3.32
3.30
3.28
VIN = 3.0V,
3.26 = 2.5V,
= 1.8V,
3.24 = 1.5V
3.22
0.1
1 10 100
LOAD CURRENT (mA)
1000
100
90
80
70
60
50
40
30
20
10
0
0.1
5.10
5.05
EFFICIENCY vs. LOAD
CURRENT, VOUT = 5V
VIN = 4.2V,
SKIP
FPWM
VIN = 4.2V,
= 3.6V,
SKIP
VIN = 3.6V,
= 3V,
= 2.4V,
= 3V,
= 2.4V,
= 1.8V,
= 1.5V
= 1.8V,
= 1.5V
1 10 100
OUTPUT CURRENT (mA)
1000
OUTPUT VOLTAGE
vs. LOAD CURRENT
FPWM
SKIP
5.00
4.95
VIN = 3.6V,
4.90 = 3V,
= 2.5V,
= 1.8V,
4.85 = 1.5V
4.80
0.1
6
1 10 100
LOAD CURRENT (mA)
OUTPUT VOLTAGE
vs. INPUT VOLTAGE
1000
5
4
3
2
1
0
1.2 2.2 3.2 4.2 5.2 6.2
INPUT VOLTAGE (V)
4 _______________________________________________________________________________________

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1A, 97% Efficiency, 30µA Quiescent Current
Step-Up Converter with True Shutdown
www.datasheet4u.com
Typical Operating Characteristics (continued)
(VOUTS = VPOUT = 5V, VBATT = VON = 3.6V, VSKIPB = GND.)
EP TEMPERATURE
vs. INPUT VOLTAGE
120
VOUT = 5V
TA = +25°C
100
IOUT = 1A
80
60
40
IOUT = 0.5A
20 MEASURED AT THE BOTTOM SIDE VIA
UNDERNEATH THE EP ON THE MAX8815A
EVALUATION KIT
0
1.2 2.2 3.2 4.2 5.2 6.2
INPUT VOLTAGE (V)
INPUT CURRENT
vs. INPUT VOLTAGE, VOUT = 3.3V
300
250
200
TA = -40°C
150 TA = +25°C
100
TA = +85°C
50
0
1.2 2.2 3.2 4.2 5.2 6.2
INPUT VOLTAGE (V)
INPUT CURRENT
vs. INPUT VOLTAGE, VOUT = 5V
200
180
160
140
TA = -40°C
TA = +85°C
120
100
80
60
40
20
0
1.2
TA = +25°C
2.2 3.2 4.2 5.2
INPUT VOLTAGE (V)
6.2
INPUT CURRENT
vs. INPUT VOLTAGE, DURING SHUTDOWN
2000
1800 TA = +85°C
1600
1400
1200
1000 TA = -40°C
800 TA = +25°C
600
400
200
0
1.2 2.2 3.2 4.2 5.2 6.2
INPUT VOLTAGE (V)
5000
4500
4000
3500
3000
2500
2000
1500
1000
500
0
0
SOFT-START TIME
vs. LOAD CURRENT
500 1000
LOAD CURRENT (mA)
1500
1200
1000
800
600
400
200
0
1.2
1600
1400
1200
1000
800
600
400
200
0
1.2
STARTUP LOAD
vs. INPUT VOLTAGE
TA = +25°C
TA = +85°C
1.8 2.4 3.0
INPUT VOLTAGE (V)
SOFT-START TIME
vs. INPUT VOLTAGE
3.6
2.2 3.2 4.2 5.2
INPUT VOLTAGE (V)
6.2
_______________________________________________________________________________________ 5