LTC3860_15 Datasheet, PDF (9/36 Pages) Linear Technology – Dual, Multiphase Step-Down Voltage Mode DC/DC Controller with Current Sharing

LTC3860
PIN FUNCTIONS
A change in V_IN immediately modulates the input to the
PWM comparator and changes the pulse width in an in-
versely proportional manner, thus bypassing the feedback
loop and providing excellent transient line regulation. An
external lowpass filter can be added to this pin to prevent
noisy signals from affecting the loop gain.
TRACK/SS1 (Pin 32), TRACK/SS2 (Pin 9): Soft-Start. The
voltage ramp rate at these pins sets the voltage ramp rate
of the outputs. Self soft-start is accomplished by placing
a capacitor to ground.
FUNCTIONAL DIAGRAM
VSNSOUT
4
VSNSP
6
DA
VSNSN
5
BG/BIAS
COMP1
3
REF
TRACK/SS1
32
FB1
2
+
+ EA1
–
REF
TRACK/SS2
9
FB2
8
COMP2
7
+
+ EA2
–
ISNS1P
22
ISNS1N
21
+
x18.5
–
ISNS2P
19
ISNS2N
20
+
x18.5
–
1
29
30
V_CC SGND SGND
V_CC
100k
24
RUN1
V_CC
100k
1.5μA
1.5μA
V_CC
17
27
14
RUN2 PGOOD1 PGOOD2
PGOOD
V_FB1
V_FB2
SD/UVLO
+
OC1 OC2
OV1 OV2
V_FB1
I_LIM1
V_FB2
I_LIM2
S
+
MASTER/SLAVE/
INDEPENDENT?
V_CC
20μA
NOC1
NOC2
LOGIC
RAMP/SLOPE/
FEEDFORWARD
V_CC
OC1
NOC1
20μA
S
V_CC
OC2
NOC2
21μA
PLL/VCO
PWM1
25
PWMEN1
26
PWM2
16
PWMEN2
15
VINSNS
31
I_AVG
28
I_LIM2
18
I_LIM1
23
FREQ PHSMD CLKOUT CLKIN
10 13
12
11
3860 BD
3860fc
9