Datasheet LTC3417A (Analog Devices) - 6

LTC3417A
pin FuncTions (DFN/TSSOP) RUN1 (Pin 1/Pin 2):
Enable for 1.5A Regulator. When oscillator applied to this pin. When synchronized to an at Logic 1, 1.5A regulator is running. When at 0V, 1.5A external clock, pulse skip mode is selected. regulator is off. When both RUN1 and RUN2 are at 0V,
SW2 (Pin 10/Pin 13):
Switch Node Connection to the the part is in shutdown. Inductor for the 1A Regulator. This pin swings from VIN2
VIN1 (Pin 2/Pin 3):
Supply Pin for P-Channel Switch of to PGND2. 1.5A Regulator.
PGOOD (Pin 11/Pin 14):
Power Good Pin. This common
ITH1 (Pin 3/Pin 4):
Error Amplifier Compensation Point drain-logic output is pulled to GND when the output voltage for 1.5A Regulator. The current comparator threshold of either regulator is –6% of regulation. If either RUN1 or increases with this control voltage. Nominal voltage range RUN2 is low (the respective regulator is in sleep mode and for this pin is 0V to 1.5V. therefore the output voltage is low), then PGOOD reflects
V
the regulation of the running regulator.
FB1 (Pin 4/Pin 5):
Receives the feedback voltage from external resistive divider across the 1.5A regulator output.
FREQ (Pin 12/Pin 15):
Frequency Set Pin. When FREQ is Nominal voltage for this pin is 0.8V. at VIN, internal oscillator runs at 1.5MHz. When a resistor
V
is connected from this pin to ground, the internal oscillator
FB2 (Pin 5/Pin 6):
Receives the feedback voltage from external resistive divider across the 1A regulator output. frequency can be varied from 0.6MHz to 4MHz. Nominal voltage for this pin is 0.8V.
GNDA (Pin 13/Pin 16):
Analog Ground Pin for Internal
I
Analog Circuitry.
TH2 (Pin 6/Pin 7):
Error Amplifier Compensation Point for 1A regulator. The current comparator threshold increases
PHASE (Pin 14/Pin 17):
Selects 1A regulator switching with this control voltage. Nominal voltage range for this phase with respect to 1.5A regulator switching. Set to VIN, pin is 0V to 1.5V. the 1.5A regulator and the 1A regulator are in phase. When
RUN2 (Pin 7/Pin 8):
Enable for 1A Regulator. When at PHASE is at 0V, the 1.5A regulator and the 1A regulator Logic 1, 1A regulator is running. When at 0V, 1A regula- are switching 180 degrees out-of-phase. tor is off. When both RUN1 and RUN2 are at 0V, the part
SW1 (Pin 15/Pin 18):
Switch Node Connection to the is in shutdown. Inductor for the 1.5A Regulator. This pin swings from
V
VIN1 to PGND1.
IN2 (Pin 8/Pin 9):
Supply Pin for P-Channel Switch of 1A Regulator and Supply for Analog Circuitry.
PGND1 (Pin 16/Pin 19):
Ground for SW1 N-Channel
SYNC/MODE (Pin 9/Pin 12):
Combination Mode Selection Driver. and Oscillator Synchronization Pin. This pin controls the op-
PGND2, GNDD (Pins 1,10,11,20):
TSSOP Package Only. eration of the device. When the voltage on the SYNC/MODE Ground for SW2 N-channel driver and digital ground for pin is >(VIN – 0.5V), Burst Mode operation is selected. circuit. When the voltage on the SYNC/MODE pin is <0.5V, pulse
Exposed Pad (Pin 17/Pin 21):
PGND2, GNDD. Ground for skipping mode is selected. When the SYNC/MODE pin is SW2 N-channel driver and digital ground for circuit. The held at VIN/2, forced continuous mode is selected. The Exposed Pad must be soldered to PCB ground. oscillation frequency can be synchronized to an external 3417afc 6 Document Outline Features Description Applications Typical Application Absolute Maximum Ratings Pin Configuration Electrical Characteristics Typical Performance Characteristics Pin Functions Functional Diagram Operation Applications Information Package Description Revision History Related Parts