F72814
F72814 Datasheet
Synchronous Buck PWM DC-DC Controller
Release Date: July, 2007
Version: V0.23P
V0.23P
F72814
F72814 Datasheet Revision History
Version
0.20P
0.21P
0.22P
0.23P
Apr, 2006
May,2006
Jul, 2007
3
4
8
11
Re-compose
Remove free run frequency
Add dead time measurement loading
Add typical characteristic diagram
Update company address
Date
Page
Revision History
Preliminary version
Please note that all data and specifications are subject to change without notice. All the trade marks of products
and companies mentioned in this data sheet belong to their respective owners.
LIFE SUPPORT APPLICATIONS
These products are not designed for use in life support appliances, devices, or systems where malfunction of these
products can reasonably be expected to result in personal injury. Customers using or selling these products for
use in such applications do so at their own risk and agree to fully indemnify Fintek for any damages resulting from
such improper use or sales.
V0.23P
F72814
Table of Content
General Description ........................................................................................................................1
Feature List .....................................................................................................................................1
Pin Configuration............................................................................................................................2
Pin Description................................................................................................................................2
Electrical Characteristic ..................................................................................................................2
Block Diagram ................................................................................................................................4
Function Description.......................................................................................................................5
7.1 Bootstrap Operation ....................................................................................................................5
7.2 Power On Reset...........................................................................................................................5
7.3 Soft-Start .....................................................................................................................................6
7.4 Over-current Protection ..............................................................................................................6
7.5 Under-voltage Protection ............................................................................................................6
7.6 Shutdown ....................................................................................................................................7
7.7 VIN Sense ...................................................................................................................................7
8. Typical Characteristic .................................................................................................................8
9.
Ordering Information ......................................................................................................................9
10.
Package Dimensions (8-SOP/150 mil) .........................................................................................11
11.
Application Circuit........................................................................................................................12
1.
2.
3.
4.
5.
6.
7.
V0.23P
F72814
1. General Description
The F72814 is a high-efficiency synchronous buck PWM controller that generates logic-supply voltages in PC based
systems. This high-performance , single output device includes internal soft-start, frequency-compensation networks, power
good signal with delay, and integrates all of the control, output adjustment, monitoring and protection functions into a single
package. This device operates at a fixed frequency, 300K Hz and provides an optimum compromise between efficiency,
external component size, and cost. Adjustable over-current protection (OCP) monitors the voltage drop across the RDS (ON)
of the lower MOSFET for synchronous buck PWM DC-DC controller. The over-current function cycles the soft-start in 4-times
hiccup mode to provide fault protection, and in a routine hiccup mode for under-voltage protection.
2. Feature List
Provides one synchronous rectified buck DC-DC PWM controller
Fast transient response (high bandwidth error amplifier; full 0~80% duty cycle)
Fixed operation frequency : 300KHz
Single loop voltage-mode control
Few external components
Output range adjustable down to 0.8V
Operates under 5V to 12V input
Drives all low cost N-channel MOSFETs
Uses MOSFET R
DS(ON)
as over current monitor, and no current sense resistor is required
0.8V internal reference voltage
±2% accuracy over line, load and temperature
Internal soft-start (typically 3 ms)
Internal loop compensation
Under voltage fault monitoring and protection
Over voltage protection
Adaptive Non-Overlapping Gate Driver
8-SOP package (150 mil)
F72814
-1-
V0.23P
F72814
3. Pin Configuration
BOOT
UGATE
GND
LGATE
1
2
3
4
8
7
6
5
PHASE
OCSET
FB
VCC
F72814
4. Pin Description
Pin No
1
Pin Name
BOOT
Description
Bootstrap supply pin for the upper gate driver. Connect the bootstrap capacitor between
BOOT pin and the PHASE pin. The bootstrap capacitor provides the charge to turn on
the upper MOSFET.
2
3
4
5
6
UGATE
GND
LGATE
VCC
FB
Higher gate drive output. Connect this pin to gate of the high side MOSFET
Power ground pin for the chip
Lower gate drive output. Connect this pin to gate of the low side MOSFET
IC supply voltage. This voltage is monitored for power-on-reset purpose.
Inverting input of the error amplifier used to compensate the feedback loop of the PWM
controller.
7
OCSET/SD
This is multi-function pin. Connecting a resistor ROCSET from this pin to PHASE, and an
internal 40uA current source from VCC. OCSET voltage can sense loading status when
low side MOSFET turn on. When OCSET voltage is under 0.1V, shut down (SD) function
will be enabled.
8
PHASE
Connect this pin to the source of the upper MOSFET and the drain of the lower MOSFET.
5. Electrical Characteristic
Absolute Maximum Ratings
PARAMETER
IC supply voltage
PHASE to GND
BOOT to PHASE
SYMBOL
VCC
VPHASE – GND
VBOOT - VPHASE
RATINGS
15
15
15
UNIT
V
V
V
F72814
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V0.23P
