Datasheet LTC3890 (Analog Devices) - 9

LTC3890
PIN FUNCTIONS TG1, TG2 (Pin 26, Pin 15):
High Current Gate Drives for Alternatively, a resistor divider on another voltage supply Top N-Channel MOSFETs. These are the outputs of float- connected to this pin allows the LTC3890 output to track ing drivers with a voltage swing equal to INTVCC – 0.5V the other supply during start-up. superimposed on the switch node voltage SW.
ITH1, ITH2 (Pin 30, Pin 12):
Error Amplifier Outputs and
PGOOD1, PGOOD2 (Pin 27, Pin 14):
Open-Drain Logic Switching Regulator Compensation Points. Each associ- Output. PGOOD1,2 is pulled to ground when the voltage ated channel’s current comparator trip point increases on the VFB1,2 pin is not within ±10% of its set point. with this control voltage.
ILIM (Pin 28):
Current Comparator Sense Voltage Range
VFB1, VFB2 (Pin 31, Pin 11):
Receives the remotely sensed Inputs. Tying this pin to SGND, FLOAT or INTVCC sets the feedback voltage for each controller from an external maximum current sense threshold to one of three different resistive divider across the output. levels for both comparators.
SENSE1+, SENSE2+ (Pin 32, Pin 10):
The (+) input to the
TRACK/SS1, TRACK/SS2 (Pin 29, Pin 13):
External differential current comparators are normally connected Tracking and Soft-Start Input. The LTC3890 regulates the to DCR sensing networks or current sensing resistors. VFB1,2 voltage to the smaller of 0.8V or the voltage on the The ITH pin voltage and controlled offsets between the TRACK/SS1,2 pin. An internal 1µA pull-up current source SENSE– and SENSE+ pins in conjunction with RSENSE set is connected to this pin. A capacitor to ground at this the current trip threshold. pin sets the ramp time to final regulated output voltage. Rev. D For more information www.analog.com 9 Document Outline Features Applications Typical Application Description Absolute Maximum Ratings Order Information Pin Configuration Electrical Characteristics Typical Performance Characteristics Pin Functions Functional Diagram Operation Applications Information Typical Applications Package Description Revision History Typical Application Related Parts