LM2744MTC/NOPB National Semiconductor, LM2744MTC/NOPB Datasheet - Page 2

• Manufacturer Part Number: LM2744MTC/NOPB
• Description: IC REG SYNC BUCK N-CH 14-TSSOP
• Manufacturer: National Semiconductor
• Series: PowerWise®r
• Type: Step-Down (Buck)r

Specifications of LM2744MTC/NOPB

• Internal Switch(s): No
• Synchronous Rectifier: Yes
• Number Of Outputs: 1
• Voltage - Output: 0.5 ~ 1.5 V
• Current - Output: 20A
• Frequency - Switching: 50kHz ~ 1MHz
• Voltage - Input: 1 ~ 16 V
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: 14-TSSOP
• For Use With: LM2744EVAL - BOARD EVALUATION LM2744
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Power - Output: -
• Other names: *LM2744MTC; *LM2744MTC/NOPB; LM2744MTC

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Connection Diagram
Ordering Information
Pin Descriptions
BOOT (Pin 1) - Bootstrap pin. This is the supply rail for the
high-side gate driver. When the high-side MOSFET turns on,
the voltage on this pin should be at least one gate threshold
above the regulator input voltage V
MOSFET. See MOSFET Gate Drivers in the Application In-
formation section for more details on how to select MOSFETs.
LG (Pin 2) - Low-gate drive pin. This is the gate drive for the
low-side N-channel MOSFET. This signal is interlocked with
the high-side gate drive HG (Pin 14), so as to avoid shoot-
through.
PGND (Pin 3) - Power ground. This is also the ground for the
low-side MOSFET driver. This pin must be connected on the
PCB ground plane, which is usually also the system ground.
SGND (Pin 4) - Signal ground. It should be connected ap-
propriately to the ground plane with due regard to good layout
practices in switching power regulator circuits.
V
PWGD (Pin 6) - Power Good pin. This is an open drain output,
which is typically meant to be connected to V
low voltage source through a pull-up resistor. The voltage on
this pin is thus pulled low under output fault conditions (un-
dervoltage or overvoltage) and also under UVLO.
I
a fixed 40 µA current. A resistor of appropriate value should
be connected between this pin and the drain of the low-side
MOSFET (switch node).
EAO (Pin 8) - Output of the error amplifier. The voltage level
on this pin is compared with an internally generated ramp
signal to determine the duty cycle. This pin is necessary for
compensating the control loop.
SEN
CC
(Pin 5) Supply rail for the control sections of the IC.
(Pin 7) - Current limit threshold setting pin. This sources
Order Number
LM2744MTCX
LM2744MTC
IN
to properly turn on the
Package Type
TSSOP-14
TSSOP-14
CC
or any other
14-Lead Plastic TSSOP
θ
JA
= 155°C/W
2
NSC Package Drawing
SS/TRACK (Pin 9) - Soft-start and tracking pin. This pin is
internally connected to the non-inverting input of the error
amplifier during soft-start, and in fact any time the SS/TRACK
pin voltage happens to be below the internal reference volt-
age. For the basic soft-start function, a capacitor of minimum
value 1nF is connected from this pin to ground. To track the
rising ramp of another power supply’s output, connect a re-
sistor divider from the output of that supply to this pin as
described in Application Information.
FB (Pin 10) - Feedback pin. This is the inverting input of the
error amplifier, which is used for sensing the output voltage
and compensating the control loop.
FREQ (Pin 11) - Frequency adjust pin. The switching fre-
quency is set by connecting a resistor of suitable value be-
tween this pin and ground. The equation for calculating the
exact value is provided in Application Information, but some
typical values (rounded up to the nearest standard values) are
324 kΩ for 100 kHz, 97.6 kΩ for 300 kHz, 56.2 kΩ for 500 kHz,
24.9 kΩ for 1 MHz.
SD (Pin 12) - IC shutdown pin. Pull this pin to V
the IC is enabled. Connect to ground to disable the IC. Under
shutdown, both high-side and low-side drives are off. This pin
also features a precision threshold for power supply sequenc-
ing purposes, as well as a low threshold to ensure minimal
quiescent current.
V
verting input of the error amplifier. Any desired reference
voltage between 0.5V to 1.5V can be connected to this pin
(with appropriate filtering if necessary).
HG (Pin 14) - High-gate drive pin. This is the gate drive for
the high-side N-channel MOSFET. This signal is interlocked
with LG (Pin 2) to avoid shoot-through.
REF
(Pin 13) - External reference. This goes to the non-in-
20106002
MTC14
MTC14
2500 Units on Tape and Reel
94 Units, Raill
Supplied As
CC
to ensure