MAX761/MAX762
12V/15V or Adjustable, High-Efficiency,
Low I
Q
, Step-Up DC-DC Converters
6 _______________________________________________________________________________________
LOAD–TRANSIENT RESPONSE
A: I
LOAD
, (0mA to 200mA)
B: V
OUT
, AC COUPLED, 100mV/div
V
IN
= 5V, V
OUT
= 12V
5µs/div
200mA
0mA
A
B
_____________________________Typical Operating Characteristics (continued)
(Circuit of Figure 2, T
A
= +25°C, unless otherwise noted.)
LINE–TRANSIENT RESPONSE
A: V
IN
(4V to 6V)
B: V
OUT
, AC COUPLED, 20mV/div
I
OUT
= 50mA, V
OUT
= 12V
5ms/div
6V
4V
A
B
NAME FUNCTION
LBO
Low-battery output is an open-drain output that goes low when LBI is less than 1.5V.
Connect to V+ through a pull-up resistor. Leave LBO floating if not used.
LBI Input to the internal low-battery comparator. Tie to GND or V+ if not used.
PIN
1
2
FB
Feedback input. For fixed-output bootstrapped operation, connect FB to GND. For
adjustable-output bootstrapped operation, connect a resistor divider between V+, FB and
GND. For non-bootstrapped operation, there is no fixed-output option. Connect a resistor
divider network between V
OUT
, FB and GND. See
Bootstrapped/Non-Bootstrapped
Modes
section.
SHDN
Active-high TTL/CMOS logic-level input. In shutdown mode (SHDN = V+), the internal
switch is turned off and the output voltage equals V+ minus a diode drop (due to the DC
path from the input to the output). Tie to GND for normal operation.
REF
1.5V reference output that can source 100µA for external loads. Bypass with 0.1µF
or larger capacitor.
GND Ground
3
4
LX
Drain of the internal N-channel FET. LX has an output resistance of 1Ω and a peak current
limit of 1A.
V+ Power-supply input. In bootstrapped mode, V+ is also the output voltage sense input.
5
6
7
8
______________________________________________________________Pin Description
