PWM controller. L6728A Datasheet

L6728A controller. Datasheet pdf. Equivalent

Part L6728A
Description High frequency single phase PWM controller
Feature www.DataSheet4U.com L6728A High frequency single phase PWM controller with Power Good Features ■ ■ .
Manufacture STMicroelectronics
Datasheet
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L6728A
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L6728A
High frequency single phase PWM controller with Power Good
Features
Flexible power supply from 5 V to 12 V
Power conversion input as low as 1.5 V
0.8 V internal reference
0.8 % output voltage accuracy
High-current integrated drivers
Power Good output
Sensorless and programmable OCP across
low-side RDS(on)
OV / UV protections
VSEN disconnection protection
Oscillator internally fixed at 600 kHz
LS-LESS to manage pre-bias start-up
Adjustable output voltage
Disable function
Internal soft-start
VFDFPN 10 package
Applications
Memory and termination supply
Subsystem power supply (MCH, IOCH, PCI)
CPU and DSP power supply
Distributed power supply
General DC / DC converters
VFQFPN 10
Description
L6728A is a single-phase step-down controller
with integrated high-current drivers that provides
complete control logic and protection to realize in
a simple way general DC-DC converters by using
a compact VFDFPN 10 package.
Device flexibility allows managing conversions
with power input VIN as low as 1.5 V and device
supply voltage ranging from 5 V to 12 V.
L6728A provides simple control loop with voltage
mode EA. The integrated 0.8 V reference allows
regulating output voltages with ±0.8 % accuracy
over line and temperature variations. Oscillator is
internally fixed to 600 kHz.
L6728A provides programmable dual level over
current protection as well as over and under
voltage protection. Current information is
monitored across the low-side MOSFET RDS(on)
saving the use of expensive and space-
consuming sense resistors.
PGOOD output easily provides real-time
information on output voltage status, through
VSEN dedicated output monitor.
Table 1.
Device summary
Order codes
L6728A
L6728ATR
Package
VFDFPN 10
VFDFPN 10
Packing
Tube
Tape and reel
October 2008
Rev 1
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L6728A
L6728A
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Contents
Contents
1 Typical application circuit and block diagram . . . . . . . . . . . . . . . . . . . . 4
1.1 Application circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.2 Block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
2 Pins description and connection diagrams . . . . . . . . . . . . . . . . . . . . . . 5
2.1 Pin descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2.2 Thermal data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
3 Electrical specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
3.1 Absolute maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
3.2 Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
4 Device description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
5 Driver section . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
5.1 Power dissipation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
6 Soft-start . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
6.1 Low-side-less start up (LSLess) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
7 Over-current protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
7.1 Over-current threshold setting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
8 Output voltage setting and protections . . . . . . . . . . . . . . . . . . . . . . . . 13
9 Application details . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
9.1 Compensation network . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
9.2 Layout guidelines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
10 Application information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
10.1 Inductor design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
10.2 Output capacitor(s) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
10.3 Input capacitors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
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