LM2742_15 Datasheet, PDF (1/33 Pages) Texas Instruments – N-Channel FET Synchronous Buck Regulator Controller for Low Output Voltages

LM2742
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SNVS266C – MARCH 2004 – REVISED MARCH 2013
LM2742 N-Channel FET Synchronous Buck Regulator Controller for Low Output Voltages
Check for Samples: LM2742
FEATURES
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•2 Input Power from 1V to 16V
• Output Voltage Adjustable down to 0.6V
• Power Good Flag, Adjustable Soft-start and
Output Enable for Easy Power Sequencing
• Reference Accuracy: 1.5% (0°C–125°C)
• Current Limit Without Sense Resistor
• Soft Start
• Switching Frequency from 50 kHz to 2 MHz
• 40ns Typical Minimum On-time
• TSSOP-14 Package
APPLICATIONS
• POL Power Supply Modules
• Cable Modems
• Set-Top Boxes/ Home Gateways
• DDR Core Power
• High-Efficiency Distributed Power
• Local Regulation of Core Power
DESCRIPTION
The LM2742 is a high-speed, synchronous, switching
regulator controller. It is intended to control currents
of 0.7A to 20A with up to 95% conversion efficiencies.
Power up and down sequencing is achieved with the
power-good flag, adjustable soft-start and output
enable features. The LM2742 operates from a low-
current 5V bias and can convert from a 1V to 16V
power rail. The part utilizes a fixed-frequency,
voltage-mode, PWM control architecture and the
switching frequency is adjustable from 50kHz to
2MHz by setting the value of an external resistor.
Current limit is achieved by monitoring the voltage
drop across the on-resistance of the low-side
MOSFET, which enables on-times on the order of
40ns, one of the best in the industry. The wide range
of operating frequencies gives the power supply
designer the flexibility to fine-tune component size,
cost, noise and efficiency. The adaptive, non-
overlapping MOSFET gate-drivers and high-side
bootstrap structure helps to further maximize
efficiency. The high-side power FET drain voltage can
be from 1V to 16V and the output voltage is
adjustable down to 0.6V.
TYPICAL APPLICATION
+5V
D1
RIN
10:
CIN
2.2 PF
RFADJ
63.4k
CSS
12n
V_CC
SD
PWGD
FREQ
SS
SGND
EAO
HG
BOOT
I_SEN
LM2742 _LG
PGND
PGND
FB
CC2
180p
CC1
RC1
2.2p
392k
CBOOT
V_IN = 3.3V
0.1P
RCS
2.2k
Q1 Si4884DY
1.5 PH
6.1A, 9.6 m:
L1
Q2 Si4884DY
R_fb2
10k
CIN1,2
10 PF
6.3V
V_O = 1.2V@5A
+
CO1,2
2200 PF
6.3V, 2.8A
R_fb1
10k
Figure 1. Typical Application Circuit
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2
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.
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