Rainbow Electronics MAX8815A - Manual

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
Features
♦ Up to 97% Efficiency with Internal Synchronous
Rectifier
♦ Low 30µA Quiescent Current
♦ Guaranteed 500mA Output Current at V
OUT = 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
MAX8815A
1A, 97% Efficiency, 30µA Quiescent Current
Step-Up Converter with True Shutdown
________________________________________________________________ Maxim Integrated Products 1
Ordering Information
19-4092; Rev 0; 5/08
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
PART PIN-PACKAGE TOP MARK
MAX8815AETB+ 10 TDFN-EP* AUH
True Shutdown is a trademark of Maxim Integrated Products, Inc.
+ Denotes a lead-free package.
* EP = Exposed pad.
Note: This device operates in the -40°C to +85°C extended
operating temperature range.
BATT
ON
SKIPB
LX
POUT
OUTS
FB
GND
INPUT VOLTAGE
1.2V TO 5.5V
OUTPUT VOLTAGE
5V UP TO 1A
MAX8815A
Typical Operating Circuit
TOP VIEW
SKIPB OUTS FB
ON
GND
1 2 3 4 5
10 9 8 7 6
POUT POUT
LX
BATT
LX
MAX8815A
+
Pin Configuration