LTC1143 Linear Technology, LTC1143 Datasheet - Page 6

• Manufacturer Part Number: LTC1143
• Description: Dual High Efficiency SO-16 Step-Down Switching Regulator Controllers
• Manufacturer: Linear Technology

LTC1143/LTC1143L
LTC1143L-ADJ
PIN
V
decoupled to 3.3V power ground Pin 3.
C
sets the operating frequency for the 3.3V section. (The
actual frequency is also dependent upon the input voltage.)
I
Section. The 3.3V section current comparator threshold
increases with the Pin 15 voltage.
SENSE
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
Comparator. A built-in offset between Pins 1 and 16 in
conjunction with R
for section 1.
V
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
(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
to ground.
V
decoupled to power ground Pin 11.
C
the operating frequency for section 2. (The actual frequency
is also dependent upon the input voltage.)
6
TH3
IN3
T3
FB1
IN2
T2
U
(Pin 14): External capacitor C
(Pin 6): External capacitor C
(Pin 13): Supply Pin, 3.3V Section. Must be closely
(Pin 15): Gain Amplifier Decoupling Point, 3.3V
(Pin 2): This pin serves as the feedback pin from an
(Pin 5): Supply Pin, Section 2. Must be closely
FUNCTIONS
+
–
1 (Pin 1): The (+) Input to the Section 1 Current
3 (Pin 16): Connects to internal resistive
U
SENSE 1
U
sets the current trip threshold
T2
T3
from Pin 6 to ground sets
from Pin 14 to ground
IN1
IN1
I
The section 2 current comparator threshold increases
with the Pin 7 voltage.
SENSE
comparator on section 2.
SENSE
Comparator. A built-in offset between Pins 9 and 8 in
conjunction with R
for section 2.
V
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
P-DRIVE 2 (Pin 12): High Current Drive for Top P-Channel
MOSFET, Section 2. Voltage swing at this pin is from V
to ground.
V
decoupled to power ground Pin 3.
C
sets the operating frequency for section 1. (The actual
frequency is also dependent upon the input voltage.)
I
The section 1 current comparator threshold increases
with the Pin 15 voltage.
SENSE
current comparator on section 1.
TH2
TH1
FB2
IN2
IN1
T1
(Pin 14): External capacitor C
(Pin 7): Gain Amplifier Decoupling Point, Section 2.
(Pin 15): Gain Amplifier Decoupling Point, Section 1.
(see Figure 1).
(Pin 10): This pin serves as the feedback pin from an
(Pin 13): Supply Pin, Section 1. Must be closely
–
+
–
2 (Pin 9): The (+) Input to the Section 2 Current
2 (Pin 8): Pin 8 is the (–) input for the current
1 (Pin 16): Pin 16 is the (–) input for the
SENSE 2
sets the current trip threshold
T1
from Pin 14 to ground
IN2