Rainbow Electronics MAX1708 - Manual

General Description
The MAX1708 sets a new standard of space savings for
high-power, step-up DC-DC conversion. It delivers up
to 10W at a fixed (3.3V or 5V) or adjustable (2.5V to
5.5V) output, using an on-chip power MOSFET from a
+0.7V to +5V supply.
Fixed-frequency PWM operation ensures that the
switching noise spectrum is constrained to the 600kHz
fundamental and its harmonics, allowing easy postfilter-
ing for noise reduction. External clock synchronization
capability allows for even tighter noise spectrum con-
trol. Quiescent power consumption is less than 1mW to
extend operating time in battery-powered systems.
Two control inputs (ONA, ONB) allow simple push-on,
push-off control through a single momentary push-but-
ton switch, as well as conventional on/off logic control.
The MAX1708 also features programmable soft-start
and current limit for design flexibility and optimum per-
formance with batteries. The maximum RMS switch cur-
rent rating is 5A. For a device with a higher (10A)
switch current rating, refer to the MAX1709 data sheet.
________________________Applications
Routers, Servers, Workstations, Card Racks
Local 2.5V to 3.3V or 5V Conversion
Local 3.3V to 5V Conversion
3.6V or 5V RF PAs in Communications Handsets
Features
♦ On-Chip 5A Power MOSFET
♦ 5V, 2A Output from a 3.3V Input
♦ Fixed 3.3V or 5V Output Voltage or
Adjustable (2.5V to 5.5V)
♦ Input Voltage Range Down to 0.7V
♦ Low Power Consumption
1mW Quiescent Power
1µA Current in Shutdown Mode
♦ Low-Noise, Constant Frequency Operation
(600kHz)
♦ Synchronizable Switching Frequency
(350kHz to 1000kHz)
♦ Small QSOP Package
MAX1708
High-Frequency, High-Power, Low-Noise,
Step-Up DC-DC Converter
________________________________________________________________ Maxim Integrated Products 1
16
15
14
13
12
11
10
9
1
2
3
4
5
6
7
8
ONB CLK
3.3/5
PGND
PGND
PGND
FB
OUT
GND
TOP VIEW
MAX1708
QSOP
ONA
LX
GND
LX
LX
SS/LIM
REF
Pin Configuration
ONA
REF
SS/LIM
CLK
OUTPUT
3.3V, 5V,
OR ADJ
UP TO 2A
OUT
GND
LX
2.2 µH
OFF ON
INPUT
1V TO 5V
SYNC
OR
INTERNAL
MAX1708
Typical Operating Circuit
19-2068; Rev 0; 7/01
Ordering Information
PART TEMP. RANGE PIN-PACKAGE
MAX1708EEE -40 °C to +85°C 16 QSOP
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.