2002 Fairchild Semiconductor Corporation
www.fairchildsemi.com
Rev. 1.0.2
Features
Complete House Keeping Circuit
Few External Components
Positive Voltage Protection
Negative Voltage Protection
High Current Drive Output for SCR
Precision Voltage Reference for 5V/12V Outputs
Power Good Signal Generator with Hysteresis
Description
The KA3501 is complete housekeeping circuits for use in the
secondary side of SMPS(Switched Mode Power Supply).
This IC(Integrated Circuit) contains a precision voltage
reference, protection circuits and a power good signal
generator. It also has a high current drive output for use in
conjunction with an external "crowbar" SCR. The reference
voltage is trimmed to
2% for correct output voltages(+5V/
+12V) and power good signal generator is to monitor the
voltage level of power good supply for safe operation in a
microprocessor circuit. Using the KA3501 requires few
external components to accomplish a complete
housekeeping circuit for SMPS(Switched Mode Power
Supply). The KA3501 is available in an 14-pin DIP.
Internal Block Diagram
Positive
Voltage
Protection
Negative
Voltage
Protection
+5V
Detecting
COMP
V
CC
Detecting
COMP
lchg
START UP
INTERNAL
BIAS
+2.5V
REFERENCE
VOLTAGE
4
7
8
11
12
10
13
1
3
9
2
14
6
5
V
CC
1(+5V)
V
CC
Vin1
PG
Ve
Vin2
GATE
Feedback
Vref
V
CC
2(+12V)
Vcont
GND
Td
Timing
KA3501
PC SMPS Supervisory IC
14-DIP
1
KA3501
2
Pin Assignments
Absolute Maximum Rating ( Ta = 25
C)
Pin Number
Pin Name
Pin Function Description
1
Vcont
Reference Voltage Control
2
Vref
Precision Reference Voltage
3
Vcc2
+12V Output Voltage
4
Vcc1
+5V Output Voltage
5
Vin2
UVP Input (Negative)
6
Gate
Gate Drive Input for SCR
7
Vcc
Supply Voltage
8
Vin1
PG Input
9
Td
Reference Voltage Delay for PG
10
Timing
PG Delay
11
PG
PG Output
12
Ve
PG Ground (Open Emitter)
13
GND
Ground
14
Feedback
Feedback for Precision Reference
Parameter
Symbol
Value
Unit
Supply Minimum Voltage
Vcc(min)
5
V
Supply Maximum Voltage
Vcc(max)
35
V
UV Input Voltage
Vuv
24
V
Minimum Gate Drive Current
I
DR
-25
V
Operating Cathode Current
I
K
1 to 30
A
Power Dissipation
Pd
1
W
Operating Temperature Range
Topr
0 to 70
C
Feedback
#1
#14
#7
#8
GND
Ve
PG
Td
Timing
Vin1
Vcont
Vref
Vcc2
Vcc1
Vin2
Gate
Vcc
K
A
3
5
0
1
KA3501
3
Electrical Characteristic
(Refer to the test circuit , Vcc=20V, Ta=25
C, unless otherwise stated)
Note:
1.These parameters, although guaranteed, are not 100% tested in production
Parameter
Symbol
Conditions
Min.
Typ. Max.
Unit
Temperature Stability for V
REF
V
REF
-
-
17
-
mV
PROTECTION SECTION
Positive Protection Voltage
V
POSI
-
5.7
6.0
6.4
V
Negative Protection Voltage
V
NEGA
Vcc1 = 5V
-1.5
-2.5
-3.5
V
Negative Input Resistor
R
NEGA
Pin 4 to Pin 5
8.5
10
11.5
k
Gate Drive Current
I
DR
V
GATE
= 0.7 V
-25
-50
-
V
REFERENCE SECTION
Reference Input Voltage
V
REF
I
K
= 10mA
2.44
2.50
2.56
V
Current Stability
V
REF
I
K
=1mA to 10mA
-
5
20
mV
Absolute Precision of Internal Three Resistors
Rint
-
-
-
20
%
Relative Deviation of Three Resistors
Rrate
-
-
0.5
3
%
Temperature Stability (Note1)
V
REF
Ta = 0 to 70
C
-
13
17
mV
Gain Bandwidth (Note1)
GBW
GV = 1
-
1
-
MHz
POWER GOOD SECTION
Detecting Input Voltage
V
IN1
-
1.23
1.28
1.33
V
Detecting PG Voltage
V
DET
-
4.1
4.3
4.5
V
Hysteresis Voltage 1
HY1
-
10
20
40
mV
Hysteresis Voltage 2
HY2
-
200
250
-
mV
Charging Current for PG Delay
I
CHG
-
-8
-14
-20
uA
PG Output Resistor
R
PG
-
7.7
9.0
10.3
k
PG Output Saturation Voltage
V
SAT
I
SINK
= 6mA
-
0.2
0.4
V
PG Output Leakage Current
I
O(LKG)
-
-
0.01
1
uA
TOTAL STANDBY CURRENT
Supply Current
Icc
V
CC
= 20V , V
CC1
= 5V
-
3
5
mA
KA3501
4
Mechanical Dimensions
Package
Dimensions in millimeters
6.40
0.20
7.62
0.300
2.54
0.100
#1
#7
#8
#14
0.252
0.008
0~15
0.25
+0.10
0.05
0.010
+0.004
0.002
3.30
0.30
0.130
0.012
3.25
0.20
0.128
0.008
19.40
0.20
0.764
0.008
19.80
0.780
MAX
5.08
0.200
0.20
0.008
MAX
MIN
2.08
0.082
()
0.46
0.10
0.018
0.004
0.059
0.004
1.50
0.10
14-DIP
KA3501
5
Ordering Information
Product Number
Package
Operating Temperature
KA3501
14-DIP
0
C ~ +70
C
KA3501
10/9/02 0.0m 001
Stock#DSxxxxxxxx
2002 Fairchild Semiconductor Corporation
LIFE SUPPORT POLICY
FAIRCHILD'S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES
OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT OF FAIRCHILD SEMICONDUCTOR
CORPORATION. As used herein:
1. Life support devices or systems are devices or systems
which, (a) are intended for surgical implant into the body,
or (b) support or sustain life, and (c) whose failure to
perform when properly used in accordance with
instructions for use provided in the labeling, can be
reasonably expected to result in a significant injury of the
user.
2. A critical component in any component of a life support
device or system whose failure to perform can be
reasonably expected to cause the failure of the life support
device or system, or to affect its safety or effectiveness.
www.fairchildsemi.com
DISCLAIMER
FAIRCHILD SEMICONDUCTOR RESERVES THE RIGHT TO MAKE CHANGES WITHOUT FURTHER NOTICE TO ANY
PRODUCTS HEREIN TO IMPROVE RELIABILITY, FUNCTION OR DESIGN. FAIRCHILD DOES NOT ASSUME ANY
LIABILITY ARISING OUT OF THE APPLICATION OR USE OF ANY PRODUCT OR CIRCUIT DESCRIBED HEREIN; NEITHER
DOES IT CONVEY ANY LICENSE UNDER ITS PATENT RIGHTS, NOR THE RIGHTS OF OTHERS.
PDF 
ZIP