LTC1142-ADJ Linear Technology, LTC1142-ADJ Datasheet - Page 7

• Manufacturer Part Number: LTC1142-ADJ
• Description: Dual High Efficiency Synchronous Step-Down Switching Regulators
• Manufacturer: Linear Technology

PI FU CTIO S
NDRIVE 1 (Pin 6): High Current Drive for Bottom N-Channel
MOSFET, Section 1. Voltage swing at Pin 6 is from ground
to V
NC (Pins 7, 8): No Connection.
PDRIVE 2 (Pin 9): High Current Drive for Top P-Channel
MOSFET, Section 2. Voltage swing at this pin is from V
to ground.
V
decoupled to section 2 power ground, Pin 19.
C
sets the operating frequency for the section 2. (The actual
frequency is also dependent upon the input voltage.)
INT V
nominally 3.3V, can be decoupled to signal ground, Pin
18. Do not externally load this pin.
I
The section 2 current comparator threshold increases
with the Pin 13 voltage.
SENSE
comparator on section 2.
SENSE
Comparator. A built-in offset between Pins 15 and 14 in
conjunction with R
for this section.
V
external resistive divider used to set the output voltage for
section 2.
SHUTDOWN 2 (Pin 17): When grounded, the section 2
regulator operates normally. Pulling Pin 17 high holds
TH2
IN2
T2
FB2
U
(Pin 11): External capacitor C
IN1
(Pin 13): Gain Amplifier Decoupling Point, Section 2.
(Pin 16): This pin serves as the feedback pin from an
(Pin 10): Supply pin, section 2, must be closely
CC2
.
–
+
2 (Pin 15): The (+) Input to the Section 2 Current
2 (Pin 14): Connects (–) input for the current
(Pin 12) : Internal supply voltage for section 2,
U
SENSE2
U
sets the current trip threshold
T2
from Pin 11 to ground
IN2
both MOSFETs off and puts section 2 in micropower
shutdown mode. Requires CMOS logic signal with t
t
SGND2 (Pin 18): The section 2 small-signal ground must
be routed separately from other grounds to the (–) termi-
nal of the section 2 output capacitor.
PGND2 (Pin 19): The section 2 driver power ground
connects to source of the N-channel MOSFET and the (–)
terminal of the section 2 input capacitor.
NDRIVE 2 (Pin 20): High Current Drive for Bottom N-
Channel MOSFET, Section 2. Voltage swing at Pin 20 is
from ground to V
NC (Pins 21, 22): No Connection.
PDRIVE 1 (Pin 23): High Current Drive for Top P-Channel
MOSFET, Section 1. Voltage swing at this pin is from V
to ground.
V
decoupled to section 1 power ground Pin 5.
C
sets the operating frequency for section 1. (The actual
frequency is also dependent upon the input voltage.)
INT V
nominally 3.3V, can be decoupled to signal ground, Pin 4.
Do not externally load this pin.
I
The section 1 current comparator threshold increases
with the Pin 27 voltage.
SENSE
current comparator on section 1.
f
TH1
LTC1142/LTC1142L/LTC1142HV
IN1
T1
< 1 s. Do not “float” Pin 17.
(Pin 25): External capacitor C
(Pin 27): Gain Amplifier Decoupling Point, Section 1.
(Pin 24): Supply Pin, Section 1. Must be closely
CC1
–
1 (Pin 28): Connects to the (–) input for the
(Pin 26): Internal supply voltage for section 1,
IN2
.
T1
from Pin 25 to ground
7
IN1
r
,