LT3690 LINER [Linear Technology], LT3690 Datasheet - Page 9

• Manufacturer Part Number: LT3690
• Description: 42V, 2.5A Synchronous Step-Down Regulator
• Manufacturer: LINER [Linear Technology]

PIN FUNCTIONS
BIAS (Pin 14): The internal regulator will draw current from
BIAS instead of V
than 3.1V. For output voltages of 3.3V and above this pin
should be tied to V
than V
PG (Pin 15): The PG pin is the open-drain output of an
internal comparator. PG remains low until the FB pin is
within ±9% of the final regulation voltage, and there are
no fault conditions. PG is valid when V
regardless of EN/UV pin state.
BLOCK DIAGRAM
V
IN
OPT
C
R2
R
R3
OPT
R4
OPT
SS
C1
T
OUT
V
OUT
C
R1
IN
use a 1μF local bypass capacitor on this pin.
15
16
4
2
3
1
V
5, 6
EN/UV
PG
FB
TR/SS
RT
SYNC
IN
IN
1V
OUT
when BIAS is tied to a voltage higher
. If this pin is tied to a supply other
2.2μA
SHDN
TSD
INTV
V
+
–
IN
±9%
UVLO
CC
INTERNAL 0.97V REF
UVLO
SHDN
ERROR
AMP
+
+
–
IN
is above 3.4V,
V
SHDN
TSD
V
C
IN
200kHz TO 2.2MHz
UVLO
SLOPE COMP
OSCILLATOR
–
+
GND
17
DETECT
BURST
FB (Pin 16): The LT8610 regulates the FB pin to 0.970V.
Connect the feedback resistor divider tap to this pin. Also,
connect a phase lead capacitor between FB and V
Typically, this capacitor is 4.7pF to 10pF.
GND (Exposed Pad Pin 17): Ground. The exposed pad
must be connected to the negative terminal of the input
capacitor and soldered to the PCB in order to lower the
thermal resistance.
THROUGH
SWITCH
SHOOT
LOGIC
ANTI-
AND
3.4V
REG
M1
M2
INTV
PGND
BIAS
9-11
BST
7, 8
SW
CC
14
13
12
8610 BD
LT8610
C
BST
C
C
L
OUT
VCC
OUT
9
8610p
V
OUT
.