LTC1474 LINER [Linear Technology], LTC1474 Datasheet - Page 5

• Manufacturer Part Number: LTC1474
• Description: Low Quiescent Current High Efficiency Step-Down Converters
• Manufacturer: LINER [Linear Technology]

FUNCTIONAL DIAGRA
PIN
V
versions, an internal resistive divider divides the output
voltage down for comparison to the internal 1.23V refer-
ence. In the adjustable versions, this divider must be
implemented externally.
LBO (Pin 2): Open Drain Output of the Low Battery
Comparator. This pin will sink current when Pin 3 is below
1.23V.
LBI/OFF (Pin 3): Input to Low Battery Comparator. This
input is compared to the internal 1.23V reference. For the
LTC1475, a momentary ground on this pin puts regulator
in shutdown mode.
GND (Pin 4): Ground Pin.
OUT
LTC1474: RUN
LTC1475: ON
U
U
/V
FUNCTIONS
FB
LBO
(Pin 1): Feedback of Output Voltage. In the fixed
U
1 A
8
2
CONNECTION NOT PRESENT IN LTC1474 SERIES
CONNECTION PRESENT IN LTC1474 SERIES ONLY
U
LBI/OFF
STRETCH
TRIGGER
U
1-SHOT
WAKEUP
LB
OUT
+
–
W
3
4.75 s
LTC1474: LBI
LTC1475: LBI/OFF
READY
ON
ON
C
V
REFERENCE
–
+
–
+
1.23V
1.23V
100mV
SW (Pin 5): Drain of Internal PMOS Power Switch. Cath-
ode of Schottky diode must be closely connected to this
pin.
SENSE (Pin 6): Current Sense Input for Monitoring Switch
Current and Source of Internal PMOS Power Switch.
Maximum switch current is programmed with a resistor
between SENSE and V
V
RUN/ON (Pin 8): On LTC1474, voltage level on this pin
controls shutdown/run mode (ground = shutdown, open/
high = run). On LTC1475, a momentary ground on this pin
puts regulator in run mode. A 100k series resistor must be
used between Pin 8 and the switch or control voltage.
IN
(Pin 7): Main Supply Pin.
V
CC
4
GND
1
(3.3V VERSION)
5
(5V VERSION)
1.68M
1M
20
3M
IN
pins.
LTC1474/LTC1475
SENSE
SW
V
7
6
5
IN
(OPTIONAL)
V
OUTPUT DIVIDER IS
IMPLEMENTED EXTERNALLY IN
ADJUSTABLE VERSIONS
OUT
R
SENSE
1
/V
FB
+
+
1474/75 FD
V
V
IN
OUT
5