MAX1709_07 Datasheet, PDF (1/14 Pages) Maxim Integrated Products – 4A, Low-Noise, High-Frequency, Step-Up DC-DC Converter

19-1724; Rev 2; 4/07
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4A, Low-Noise, High-Frequency,
Step-Up DC-DC Converter
General Description
The MAX1709 sets a new standard of space savings for
high-power, step-up DC-DC conversion. It delivers up
to 20W 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 pushbut-
ton switch, as well as conventional on/off logic control.
The MAX1709 also features programmable soft-start
and current limit for design flexibility and optimum per-
formance with batteries.
The MAX1709 is supplied in both a high-power TSSOP
package, which allows a 10A_RMS switch current and a
4A output, and a narrow SO package, which supplies a
2.4A output with a switch rated at 6A_RMS. Although the
narrow SO device has a lower RMS switch rating, it has
the same peak switch current rating as the TSSOP
device, and so can supply 4A loads intermittently. If
loads of 2A or less are required, refer to the MAX1708.
________________________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
Typical Operating Circuit
INPUT
1V TO 5V
1μH
OFF ON
SYNC
OR
INTERNAL
ONA
LX
MAX1709
CLK
GND
SS/LIM
REF
OUT
OUTPUT
3.3V, 5V,
OR ADJ
UP TO 4A
Features
♦ On-Chip 10A Power MOSFET
♦ 5V, 4A 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)
Ordering Informations
PART
TEMP RANGE PIN-PACKAGE
MAX1709ESE
-40°C to +85°C 16 Narrow SO
MAX1709EUI+
-40°C to +85°C 28 TSSOP-EP*
+Indicates lead(Pb)-free/RoHS-compliant package.
*Exposed pad.
Pin Configurations
TOP VIEW
ONA 1
LX 2
LX 3
LX 4
LX 5
LX 6
LX 7
LX 8
NC 9
NC 10
GND 11
SS/ILM 12
REF 13
GND 14
MAX1709
28 ONB
27 CLK
26 3.3/5
25 NC
24 NC
23 PGND
22 PGND
21 PGND
20 PGND
19 PGND
18 PGND
17 NC
16 FB
15 OUT
TSSOP-EP*
Pin Configurations continued at end of data sheet.
________________________________________________________________ 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.