AS3845D813 Astec Power, AS3845D813 Datasheet
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AS3845D813
Manufacturer Part Number
AS3845D813
Description
SOP8
Manufacturer
Astec Power
Datasheet
1.AS3845D813.pdf
(14 pages)
Specifications of AS3845D813
Date_code
05+
SEMICONDUCTOR
Features
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Pin Configuration —
Ordering Information
www.ptcc.com.tw
COMP
I
R
SENSE
T
2.5 V bandgap reference trimmed to
1.0% and temperature-compensated
Standard temperature range extended
to 105°C
AS3842/3 oscillations trimmed for
precision duty cycle clamp
AS3844/5 have exact 50% max duty
cycle clamp
Advanced oscillator design simplifies
synchronization
Improved specs on UVLO and
hysteresis provide more predictable
start-up and shutdown
Improved 5 V regulator provides better
AC noise immunity
Guaranteed performance with current
sense pulled below ground
V
/C
FB
T
Circuit Type:
Package Style
Current Mode Controller (See Table A)
14D =
1
2
3
4
8D =
N =
14
PDIP (N)
8
8
Pin Plastic SOIC
Pin Plastic SOIC
Pin Plastic DIP
8
7
6
5
V
V
OUT
GND
REG
CC
Top view
Current Mode Controller
COMP
I
R
SENSE
T
V
/C
AS384x
FB
T
Description
The AS3842 family of control ICs provide pin-for-pin replacement of the
industry standard UC3842 series of devices. The devices are
redesigned to provide significantly improved tolerances in power supply
manufacturing. The 2.5 V reference has been trimmed to 1.0%
tolerance. The oscillator discharge current is trimmed to provide guar-
anteed duty cycle clamping rather than specified discharge current. The
circuit is more completely specified to guarantee all parameters impact-
ing power supply manufacturing tolerances.
In addition, the oscillator and flip-flop sections have been enhanced to
provide additional performance. The R
chronization input that can be easily driven from open collector/open
drain logic outputs. This sync input is a high impedance input and can
easily be used for externally clocked systems. The new flip-flop topol-
ogy allows the duty cycle on the AS3844/5 to be guaranteed between
49 and 50%. The AS3843/5 requires less than 0.5 mA of start-up cur-
rent over the full temperature range.
1
2
3
4
AS384X 8D N
8L SOIC (8D)
61
Table A
AS3842
AS3843
AS3844
AS3845
8
7
6
5
Model
V
V
OUT
GND
REG
CC
V
CC(min)
7.6
7.6
10
10
COMP
I
R
Packaging Option:
SENSE
T
N
T
V
NC
NC
NC
/C
FB
T
= Tape and Reel (13" Reel Dia)
= Tube
T
1
2
3
4
5
6
7
V
/C
CC(on)
8.4
8.4
16
16
T
14L SOIC (14D)
pin now doubles as a syn-
Duty Cycle
49.5%
49.5%
Typ.
97%
97%
14
13
12
11
10
9
8
V
NC
V
V
OUT
PWR GND
GND
REG
CC
C
0.5 mA
0.3 mA
0.5 mA
0.3 mA
I
CC