SEMTECH SC4431CSK-1TR

SC4431
SHUNT REGULATOR WITH OPEN
COLLECTOR OR OUTPUT
PRELIMINARY - September 11, 2000
TEL:805-498-2111 FAX:805-498-3804 WEB:http://www.semtech.com
DESCRIPTION
FEATURES
•= Trimmed bandgap design - initial accuracies to
The SC4431 is a four terminal device for regulating an
isolated power supply with very low output voltage.
•=
•=
•=
•=
It is intended to be used as a replacement for three terminal shunt regulators such as SC431L where the output voltage is too low for them to function in conjunction with an opto-isolator. It achieves this by having
seperate supply and output pins, allowing the output to
sink current at voltages as low as 0.2V, while the supply pin still has sufficient voltage for the device to function. In this way, allowing for a 1.6V drop through an
opto-isolator diode, regulation down to 1.8V out can be
achieved.
+ 0.5%
40mA drive capability
Wide supply voltage range - 1.5V to 15V
Low supply current - typically 110µA
Full industrial temperature range
APPLICATIONS
•= Opto driver for very low output voltage isolated
power supplies
The SC4431 shunt regulator is available with three initial reference voltage accuracies (0.5%, 1.0% and
2.0%) in the space saving 5-lead SOT-23 package.
The three voltage tolerances allow the designer the
opportunity to select the proper cost/tolerance for their
application.
ORDERING INFORMATION
(1)(2)
Part Number
Package
SC4431CSK-X.TR
SOT-23-5
Notes:
(1) Where “-X” denotes initial reference voltage tolerance. Available options are ±0.5% (-.5), ±1% (-1) and
±2% (-2).
(2) Only available in tape and reel packaging. A reel
contains 3000 devices.
TYPICAL APPLICATION CIRCUIT
2V OUT
T1
VIN
Primary Side
Controller
Secondary Side
Rectification
and Filtering
R1
U1
R2
C1
5.1k
33nF
U2
1
R3
6.34k
SC4431
VCC
5
OUT
REF
4
4N25
C2
22nF
NC
3
R4
10k
GND
2
2V Output Isolated Power Supply
1
© 2000 SEMTECH CORP.
652 MITCHELL ROAD NEWBURY PARK CA 91320
SC4431
SHUNT REGULATOR WITH OPEN
COLLECTOR OR OUTPUT
PRELIMINARY - September 11, 2000
ABSOLUTE MAXIMUM RATINGS
Parameter
Symbol
Maximum
Units
Input Supply Voltage
VCC
-0.5 to +16
V
Output Voltage
VOUT
-0.5 to VCC
V
Reference Voltage
VREF
-0.5 to +4
V
Continuous Output Current
IOUT
40
mA
Reference Input Current
IREF
5
mA
Operating Ambient Temperature Range
TA
-40 to +85
°C
Operating Junction Temperature Range
TJ
-40 to +150
°C
TSTG
-65 to +150
°C
Thermal Impedance Junction to Ambient
θJA
256
°C/W
Thermal Impedance Junction to Case
θJC
81
°C/W
Power Dissipation at TA = 25°C
PD
475
mW
Lead Temperature (Soldering) 10 seconds
TLEAD
300
°C
ESD Rating (Human Body Model)
ESD
2
kV
Storage Temperature Range
ELECTRICAL CHARACTERISTICS
Unless specified, TA = 25°C, VCC = 2V, IOUT = 2mA. Values in bold apply over full operating temperature range.
Parameter
Symbol
Test Conditions
MIN
TYP
MAX
Units
15
V
VCC
Input Supply Voltage
VCC
Input Supply Current
ICC
VREF = VOUT
110
200
µA
ICC(OFF)
VREF = 1.187V, VOUT = 2V
65
100
µA
Off State Input Supply Current
1.5
150
REF
Reference Voltage
VREF
SC4431-.5, VREF = VOUT
1.219 1.224 1.231
1.207
SC4431-1, VREF = VOUT
1.243
1.212 1.224 1.236
1.200
SC4431-2, VREF = VOUT
in VCC
Change in VREF due to change
in IOUT
dVREF
dVCC
VCC = 1.5V to 15V
dVREF
dIOUT
IOUT = 0.1mA to 40mA
V
1.250
1.200 1.224 1.250
1.187
Change in VREF due to change
V
V
1.261
8
15
mV
20
8
28
mV
36
2
© 2000 SEMTECH CORP.
652 MITCHELL ROAD NEWBURY PARK CA 91320
SC4431
SHUNT REGULATOR WITH OPEN
COLLECTOR OR OUTPUT
PRELIMINARY - September 11, 2000
ELECTRICAL CHARACTERISTICS (Cont.)
Unless specified, TA = 25°C, VCC = 2V, IOUT = 2mA. Values in bold apply over full operating temperature range.
Parameter
Symbol
Test Conditions
IREF
0.1mA ≤ IOUT ≤ 10mA
MIN
TYP
MAX
Units
0.3
0.5
µA
REF (Cont.)
Reference Input Current
1.0
OUT
Saturation Voltage
VOUT(SAT)
IOUT = 5mA, ICC = 500µA
50
75
mV
100
VREF = 1.261V, IOUT = 40mA
275
300
mV
400
Off State Output Current
IOUT(OFF)
VREF = 1.187V, VOUT = 2V
0.5
1
µA
10
3
© 2000 SEMTECH CORP.
652 MITCHELL ROAD NEWBURY PARK CA 91320
SHUNT REGULATOR WITH OPEN
COLLECTOR OR OUTPUT
SC4431
PRELIMINARY - September 11, 2000
BLOCK DIAGRAM
PIN CONFIGURATION
SOT-23 -5 Lead (Top View)
PIN DESCRIPTION
Pin
Pin Name Pin Function
1
VCC
This is the input supply pin for the IC.
2
GND
Logic and power ground.
3
NC
No connection.
4
REF
This is connected to the non-inverting input of the error amplifier.
5
OUT
This is the output pin of the device, essentially an open collector.
4
© 2000 SEMTECH CORP.
652 MITCHELL ROAD NEWBURY PARK CA 91320
SHUNT REGULATOR WITH OPEN
COLLECTOR OR OUTPUT
SC4431
PRELIMINARY - September 11, 2000
DEVICE OUTLINE - SOT-23-5
LAND PATTERN - SOT-23-5
ECN 00-1315
5
© 2000 SEMTECH CORP.
652 MITCHELL ROAD NEWBURY PARK CA 91320