ltc1772bes6-trpbf Linear Technology Corporation, ltc1772bes6-trpbf Datasheet - Page 4

• Manufacturer Part Number: ltc1772bes6-trpbf
• Description: Constant Frequency Current Mode Step-down Dc/dc Controller In Sot-23
• Manufacturer: Linear Technology Corporation

FUNCTIONAL DIAGRA
I
serves as the error amplifier compensation point as well as
the run control input. The current comparator threshold
increases with this control voltage. Nominal voltage range
for this pin is 0.7V to 1.9V. Forcing this pin below 0.35V
causes the device to be shut down. In shutdown all
functions are disabled and the PGATE pin is held high.
GND (Pin 2): Ground Pin.
LTC1772
PIN
4
TH
/RUN (Pin 1): This pin performs two functions. It
U
U
FUNCTIONS
0.3V
V
U
IN
GND
V
5
2
IN
U
SENSE
4
4
U
–
FOLDBACK
FREQ
OSC
+
–
SHORT-CIRCUIT
+
–
DETECT
W
ICMP
0.5µA
UNDERVOLTAGE
SLOPE
COMP
REFERENCE
LOCKOUT
VOLTAGE
V
–
+
IN
0.15V
0.3V
V
0.8V
REF
V
nal resistive divider across the output.
SENSE
parator.
V
Pin 2.
PGATE (Pin 6): Gate Drive for the External P-Channel
MOSFET. This pin swings from 0V to V
FB
IN
0.35V
(Pin 5): Supply Pin. Must be closely decoupled to GND
(Pin 3): Receives the feedback voltage from an exter-
1
+
–
I
–
RS1
R
S
TH
(Pin 4): The Negative Input to the Current Com-
/RUN
Q
+
–
SHDN
CMP
BURST
CMP
SLEEP
SWITCHING
LOGIC AND
BLANKING
CIRCUIT
SHDN
UV
EAMP
OVP
+
–
+
–
1.2V
IN
V
IN
V
+
60mV
V
0.8V
.
REF
REF
V
IN
1772 FD
PGATE
V
6
3
FB
1772fb