High Performance Current Mode PWM Power Switch
SN3F
GENERAL DESCRIPTION
SN3F combines a dedicated current mode PWM
controller with a high voltage power MOSFET. It is
optimized for high performance, low standby
power, and cost effective off-line flyback converter
applications.
SN3F offers complete protection coverage with
automatic recovery feature including Cycle-by-
Cycle current limiting (OCP), over load protection
(OLP), over temperature protection (OTP), over
voltage protection and VDD under voltage lockout
(UVLO). Excellent EMI performance is achieved
with On-Bright proprietary frequency shuffling
technique together with soft switching control at
the totem pole gate drive output.
The tone energy at below 20KHZ is minimized in
the design and audio noise is eliminated during
operation.
SN3F is offered in DIP8 package.
FEATURES
Standby power lower than 100mW at
universal AC input
■
Power on soft start reducing power MOSFET
Vds stress
■
Frequency shuffling for EMI
■
Extended burst mode control for improved
efficiency and minimum standby power design
■
Audio noise free operation
■
Fixed 65KHZ (typical) switching frequency
■
Internal synchronized slope compensation
■
Low VDD startup current and low operating
current
■
Leading edge blanking on current sense input
■
Comprehensive protection coverage
o
VDD under voltage lockout with hysteresis
(UVLO)
o
Over temperature protection (OTP) with
auto- recovery
o
On-Bright
proprietary
line
input
compensated
o
Cycle-by-Cycle
over-current
threshold
setting for constant output power limiting
over universal input voltage range.
o
Accurate overload protection (OLP).
o
Over voltage protection(OVP)
o
Secondary rectifier short protection
■
APPLICATIONS
Offline AC/DC flyback converter for
■
AC/DC adapter
■
PDA power supplies
■
Digital cameras and camcorder adapter
■
VCR, SVR, STB, DVD&DVCD Player SMPS
■
Set-top box power
■
Auxiliary power supply for PC and Server
■
Open-frame SMPS
rig
ht
AC IN
EMI
Filter
co
TYPICAL APPLICATION
nf
id
en
GND
GND
Drain
Drain
tia
lt
o
盈
SN3F
n-
B
VDD_G
VDD
FB
Sense
O
Output Power Table
Product
SN3F
230VAC±15%
Adapter
1
23W
85-265VAC
Adapter
1
18W
Notes:
1. Maximum practical continuous power in an adapter design with sufficient drain pattern as a heat sink, at 40℃ ambient.
©On-Bright Electronics
Confidential
-1-
Preliminary Datasheet
OB_DOC_DS_SN3F01
源
DC Out
High Performance Current Mode PWM Power Switch
SN3F
GENERAL INFORMATION
Pin Configuration
The SN3F is offered in DIP8 package as shown
below.
Package Dissipation Rating
Package
RJA (℃/W)
DIP8
75
2
Note:
Drain Pin Connected to 100mm PCB copper clad.
Absolute Maximum Ratings
Parameter
Value
Drain voltage (off state)
-0.3V to BVdss
VDD voltage
-0.3V to 30 V
VDD-G input voltage
-0.3V to 30 V
FB input voltage
-0.3 to 7V
Sense input voltage
-0.3 to 7V
Min/Max operating junction
-40 to 150℃
temperature T
J
Min/Max storage temperature
-55 to 150℃
T
stg
Lead temperature (soldering,
260℃
10secs)
Note:
Stresses beyond those listed under “absolute
co
Current Mode PWM Power Switch
nf
id
en
SN3F
X
Package
A:DIP8
Ordering Information
Part Number
Description
SN3FAP
DIP8, Pb-free
maximum ratings” may cause permanent damage to the device.
These are stress ratings only, functional operation of the
device at these or any other conditions beyond those indicated
under “recommended operating conditions” is not implied.
Exposure to absolute maximum-rated conditions for extended
periods may affect device reliability.
O
n-
B
©On-Bright Electronics
rig
ht
Confidential
-2-
tia
X
lt
P : Pb-free
o
Package Pb-free
盈
Preliminary Datasheet
OB_DOC_DS_SN3F01
源
High Performance Current Mode PWM Power Switch
SN3F
Marking Information
VDD-G
VDD
FB
Sense
Drain
GND
P
P
I
I
O
P
Internal gate driver power supply
IC DC power supply Input
Current sense input
HV MOSFET drain pin. The drain pin is connected to the primary lead of the
transformer
Ground
O
n-
B
©On-Bright Electronics
rig
ht
co
nf
id
en
Confidential
-3-
Feedback input pin. The PWM duty cycle is determined by voltage level into this pin
and the current-sense signal at Pin 4.
tia
lt
Preliminary Datasheet
OB_DOC_DS_SN3F01
Pin Name
I/O
Description
o
TERMINAL ASSIGNMENTS
盈
源
High Performance Current Mode PWM Power Switch
SN3F
BLOCK DIAGRAM
VDD_G
1
Drain
5/6
Power
MOSFET
Current
Reference OTP
VDD
2
Internal supply
LDO
R
S
OSC
Burst mode
Soft
Driver
OCP
Extended
Slope
o
lt
compensation
盈
SENSE
4
LEB
Internal supply
R
R
FB
3
Q
Soft Start
UVLO
POR
CPL
Vth
OVP
Burst
mode
O
n-
B
©On-Bright Electronics
rig
ht
co
nf
id
en
PWM Comparator
Debounce
7/8 GND
Confidential
-4-
tia
OLP
Preliminary Datasheet
OB_DOC_DS_SN3F01
源
High Performance Current Mode PWM Power Switch
SN3F
ELECTRICAL CHARACTERISTICS
(T
A
= 25℃, VDD=16V, unless otherwise noted)
Symbol
Parameter
Supply voltage (VDD)
I
startup
I
VDD_Operation
VDD start up current
Test Conditions
VDD=UVLO(OFF)-1V,
measure leakage current
into VDD
V
FB
=3V
7.0
Min
Typ
2
1.6
8.0
Max
10
Unit
uA
rig
ht
Operation current
VDD
under
voltage
UVLO(ON)
lockout enter
VDD
under
voltage
UVLO(OFF)
lockout exit (recovery)
Over voltage protection
OVP(ON)
voltage
Feedback input section(FB pin)
V
FB_OPEN
V
FB
open loop voltage
FB pin short circuit
I
FB_SHORT
current
Zero duty cycle FB
V
TH_0D
threshold voltage
The
threshold
enter
V
ref_Green
green mode
The threshold exit burst
V
ref_burst_H
mode
The threshold enter burst
V
ref_burst_L
mode
Power limiting
FB
V
TH_PL
threshold Voltage
Power limiting debounce
T
D
_
PL
time
Z
FB_IN
Input impedance
Current sense Input(Sense pin)
Soft start time
Leading edge blanking
T
blanking
time
Z
SENSE_IN
Input Impedance
15.2
CS=0V,FB=3V Ramp up
VDD until gate clock is off
27.5
盈
16.2
29
5.5
0.35
0.8
2.25
1.45
1.35
4.6
50
15.7
4
320
40
6.1
80
0.75
65
5
5
70
75
25
80
lt
4.9
0.72
60
70
620
o
tia
Short FB pin to GND and
measure current
nf
id
en
From over current occurs
till the gate driver output
start to turn off
FB=3.3V
FB=3.3V, CS =0V
Confidential
-5-
co
T
D_OC
V
TH_OC
F
OSC
Over current detection
and control delay
Internal current limiting
threshold voltage
n-
B
Oscillator
O
△f
Temp
△f
VDD
D
max
F
Burst
Normal
oscillation
frequency
Frequency temperature
stability
Frequency
voltage
stability
Maximum duty cycle
Burst
mode
base
frequency
MOSFET
drain-source
breakdown voltage
Mosfet section
BVdss
V
©On-Bright Electronics
Preliminary Datasheet
OB_DOC_DS_SN3F01
源
mA
V
9.0
17.2
V
V
V
mA
V
V
V
V
V
mSec
Kohm
ms
ns
Kohm
nSec
0.78
V
KHZ
%
%
%
KHZ
30.5
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