ltc3890 Linear Technology Corporation, ltc3890 Datasheet - Page 9

• Manufacturer Part Number: ltc3890
• Description: 60v Low Iq, Dual, 2-phase Synchronous Step-down Dc/dc Controller
• Manufacturer: Linear Technology Corporation

TG1, TG2 (Pin 26, Pin 15): High Current Gate Drives for
Top N-Channel MOSFETs. These are the outputs of fl oat-
ing drivers with a voltage swing equal to INTV
superimposed on the switch node voltage SW.
PGOOD1, PGOOD2 (Pin 27, Pin 14): Open-Drain Logic
Output. PGOOD1,2 is pulled to ground when the voltage
on the V
I
Inputs. Tying this pin to SGND, FLOAT or INTV
maximum current sense threshold to one of three different
levels for both comparators.
TRACK/SS1, TRACK/SS2 (Pin 29, Pin 13): External
Tracking and Soft-Start Input. The LTC3890 regulates the
V
TRACK/SS1,2 pin. An internal 1μA pull-up current source
is connected to this pin. A capacitor to ground at this
pin sets the ramp time to fi nal regulated output voltage.
PIN FUNCTIONS
LIM
FB1,2
(Pin 28): Current Comparator Sense Voltage Range
voltage to the smaller of 0.8V or the voltage on the
FB1,2
pin is not within ±10% of its set point.
CC
CC
sets the
– 0.5V
Alternatively, a resistor divider on another voltage supply
connected to this pin allows the LTC3890 output to track
the other supply during start-up.
ITH1, ITH2 (Pin 30, Pin 12): Error Amplifi er Outputs and
Switching Regulator Compensation Points. Each associ-
ated channel’s current comparator trip point increases
with this control voltage.
V
feedback voltage for each controller from an external
resistive divider across the output.
SENSE1
differential current comparators are normally connected
to DCR sensing networks or current sensing resistors.
The ITH pin voltage and controlled offsets between the
SENSE
the current trip threshold.
FB1
, V
–
FB2
+
and SENSE
, SENSE2
(Pin 31, Pin 11): Receives the remotely sensed
+
+
(Pin 32, Pin 10): The (+) input to the
pins in conjunction with R
LTC3890
SENSE
9
3890f
set