1-Cell to 3-Cell, High-Power (1A),
Low-Noise, Step-Up DC-DC Converters
MAX1700/MAX1701
Pin Description
PIN
MAX1700
—
—
3
MAX1701
1
2
3
LBP
LBN
REF
Low-Battery Comparator Non-Inverting Input
Low-Battery Comparator Inverting Input
Reference Output. Bypass with a 0.22µF capacitor to GND. REF can source up to
50µA.
Switching-Mode Selection and External-Clock Synchronization Inputs.
• CLK/SEL=Low: Low-power, delivers up to 10% of full load current.
• CLK/SEL=High: High-power PWM mode. Full output power available. Operates in
low-noise, constant-frequency mode.
• CLK/SEL=External Clock: High-power PWM mode with the internal oscillator
synchronized to the external clock.
Turning on with CLK/SEL=0V also serves as a soft-start function since peak inductor
current is limited to 25% of that allowed in PWM mode.
Ground
Power-Okay Comparator Output. Open drain N-channel output is low when V
OUT
is
10% below regulation point. No internal delay is provided.
Shutdown Input. When
ONB
=high and ONA=low, the IC is off and the load is connect-
ed to the battery through the Schottky diode.
Turn ON Input. When ONA=high or
ONB
=low, the IC turns on.
Gain Block Output. This open-drain output sinks when V
AIN
<V
REF
.
Gain Block AIN input. When AIN is low, AO sinks current. The transconductance from
AIN to AO is 9mmhos.
DC-DC Converter Dual-Mode Feedback Input. For a fixed output voltage of +3.3V,
connect FB to GND. For adjustable output, connect a divider between POUT and GND
to set the output voltage in the range of 2.5V to 5V.
Source of N-Channel Power MOSFET Switch. Connect to high-current ground path.
Drain of P-Channel Synchronous Rectifier and N-Channel Switch
Output Sense Input. Power source for the IC.
Source of P-Channel Synchronous Rectifier MOSFET Switch. Connect an external
Schottky diode from LX to POUT.
Low-Battery Comparator Output. Open-drain N-channel output is low when LBN > LBP
Input hysteresis is 15mV.
Internal Connection. Leave open or connect to GND.
NAME
FUNCTION
4
4
CLK/SEL
5
—
7
8
—
—
5
6
7
8
9
10
GND
POK
ONB
ONA
AO
AIN
11
12
13
14
15
—
1, 2, 6, 9,
10, 16
11
12
13
14
15
16
—
FB
PGND
LX
OUT
POUT
LBO
I.C.
8
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MAXIM [ MAXIM INTEGRATED PRODUCTS ]
