Pin description – Rainbow Electronics MAX1698 User Manual
Page 5
MAX1698
High-Efficiency Step-Up
Current Regulator for LEDs
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5
NAME
FUNCTION
1
V
CC
IC Supply Voltage Input. Power for internal circuitry. Input range is 2.7V to 5.5V.
2
SHDN
Active-Low Shutdown Input. In shutdown, the MOSFET turns off, but a current path still exists between the
input and output. The minimum forward voltage of the LED array must exceed the maximum V
BATT
to ensure
that the LEDs are off in shutdown.
PIN
3
REF
1.25V Reference Output. Capable of sourcing 150µA for external loads. This pin is internally compensated.
Do not connect any bypass capacitors at REF.
4
ADJ
Adjust Input. Allows dynamic adjustment of the output current. FB regulates to 300mV when ADJ = REF.
6
FB
Feedback Input. Connect to the external LED current-sense feedback resistor.
8
PGND
Power Ground
9
CS
FET Current-Sense Input
5, 7
GND
Ground
10
EXT
Gate Driver Output
Pin Description
UNDERVOLTAGE
LOCKOUT/
SHUTDOWN
CS
PGND
EXT
REF
GND
ADJ
FB
SHDN
V
L
V
CC
V
CC
MAX t
ON
MIN t
OFF
MAX1698
SOFT-START
1.25V REFERENCE
Figure 1. Functional Diagram