LTC1143L_15 Datasheet, PDF (6/20 Pages) Linear Technology – Dual High Efficiency SO-16 Step-Down Switching Regulator Controllers

LTC1143/LTC1143L
LTC1143L-ADJ
PIN FUNCTIONS
V_IN3 (Pin 13): Supply Pin, 3.3V Section. Must be closely
decoupled to 3.3V power ground Pin 3.
C_T3 (Pin 14): External capacitor C_T3 from Pin 14 to ground
sets the operating frequency for the 3.3V section. (The
actual frequency is also dependent upon the input voltage.)
I_TH3 (Pin 15): Gain Amplifier Decoupling Point, 3.3V
Section. The 3.3V section current comparator threshold
increases with the Pin 15 voltage.
SENSE^– 3 (Pin 16): Connects to internal resistive
divider which sets the output voltage for the 3.3V
section. Pin 16 is also the (–) input for the current
comparator on the 3.3V section.
LTC1143L-ADJ
SENSE⁺ 1 (Pin 1): The (+) Input to the Section 1 Current
Comparator. A built-in offset between Pins 1 and 16 in
conjunction with R_{SENSE 1} sets the current trip threshold
for section 1.
V_FB1 (Pin 2): This pin serves as the feedback pin from an
external resistive divider used to set the output voltage for
section 1.
GND1 (Pin 3): Section 1 Ground. Two independent ground
lines must be routed separately from other grounds to: 1)
the (–) terminal of the section 1 output capacitor and 2) the
cathode of the Schottky diode D1 and (–) terminal of C_IN1
(see Figure 1).
P-DRIVE 1 (Pin 4): High Current Drive for Top P-Channel
MOSFET, Section 1. Voltage swing at this pin is from V_IN1
to ground.
V_IN2 (Pin 5): Supply Pin, Section 2. Must be closely
decoupled to power ground Pin 11.
C_T2 (Pin 6): External capacitor C_T2 from Pin 6 to ground sets
the operating frequency for section 2. (The actual frequency
is also dependent upon the input voltage.)
I_TH2 (Pin 7): Gain Amplifier Decoupling Point, Section 2.
The section 2 current comparator threshold increases
with the Pin 7 voltage.
SENSE^– 2 (Pin 8): Pin 8 is the (–) input for the current
comparator on section 2.
SENSE⁺ 2 (Pin 9): The (+) Input to the Section 2 Current
Comparator. A built-in offset between Pins 9 and 8 in
conjunction with R_{SENSE 2} sets the current trip threshold
for section 2.
V_FB2 (Pin 10): This pin serves as the feedback pin from an
external resistive divider used to set the output voltage for
section 2.
GND2 (Pin 11): Section 2 Ground. Two independent
ground lines must be routed separately from other grounds
to: 1) the (–) terminal of section 2 output capacitor and 2)
the cathode of the Schottky diode D2 and (–) terminal of
C_IN2 (see Figure 1).
P-DRIVE 2 (Pin 12): High Current Drive for Top P-Channel
MOSFET, Section 2. Voltage swing at this pin is from V_IN2
to ground.
V_IN1 (Pin 13): Supply Pin, Section 1. Must be closely
decoupled to power ground Pin 3.
C_T1 (Pin 14): External capacitor C_T1 from Pin 14 to ground
sets the operating frequency for section 1. (The actual
frequency is also dependent upon the input voltage.)
I_TH1 (Pin 15): Gain Amplifier Decoupling Point, Section 1.
The section 1 current comparator threshold increases
with the Pin 15 voltage.
SENSE^– 1 (Pin 16): Pin 16 is the (–) input for the
current comparator on section 1.
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