LT1610 Linear Technology, LT1610 Datasheet - Page 5

• Manufacturer Part Number: LT1610
• Description: Constant-Current/ Constant-Voltage 1.4MHz Step-Up DC/DC Converter
• Manufacturer: Linear Technology

BLOCK DIAGRA
PIN
V
tion network must be connected to this pin, either internal
(COMP pin) or external series RC to ground. 220k /
220pF typical value.
FB (Pin 2): Feedback Pin. Reference voltage is 1.23V.
Connect resistive divider tap here. Minimize trace area at
FB. Set V
SHDN (Pin 3): Shutdown. Ground this pin to turn off
device. Tie to 1V or more to enable.
PGND (Pin 4): Power Ground. Tie directly to local ground
plane.
C
(Pin 1): Error Amplifier Output. Frequency compensa-
U
FUNCTIONS
OUT
V
U
OUT
R1
(EXTERNAL)
R2
(EXTERNAL)
according to V
FB
FB
2
U
V
6
IN
Q1
W
R5
40k
OUT
= 1.23V (1 + R1/R2).
Q2
R3
30k
R6
40k
R4
140k
10
OSCILLATOR
GENERATOR
+
–
V
Figure 2. LT1610 Block Diagram
IN
1.7MHz
RAMP
A1
g
m
BIAS
SW (Pin 5): Switch Pin. Connect inductor/diode here.
Minimize trace area at this pin to keep EMI down.
V
GND (Pin 7): Signal Ground. Carries all device ground
current except switch current. Tie to local ground plane.
COMP (Pin 8): Internal Compensation Network. Tie to V
pin, or let float if external compensation is used. Output
capacitor must be tantalum if COMP pin is used for com-
pensation.
–
+
IN
1
8
R
A2
V
(Pin 6): Input Supply Pin. Must be locally bypassed.
COMP
C
C
C
C
COMPARATOR
+
–
R
FF
S
ENABLE
Q
A = 3
SHUTDOWN
+
–
DRIVER
3
7
5
4
Q3
0.15
GND
SW
SHDN
PGND
1610 F02
LT1610
5
C