General description
The WS337L is an adjustable 3-terminal negative voltage regulator capable of supplying 100mA over a 1.2V to 37V output range. It is
exceptionally easy to use and requires only two external resistors to set the output voltage. Furthermore, both line and load regulation are
better than standard fixed regulators, Also, the WS337L is packaged in a standard TO-92 transistor package which is easy to use.
In addition to higher performance than fixed regulators, the WS337L offers full overload protection. Included on the chip are current limit,
thermal overload protection and safe area protection. All overload protection circuitry remains fully functional even if the adjustment
terminal is disconnected.
Normally, only a single 1 F solid tantalum output capacitor is needed unless the device is situated more than 6 inches from the input
filter capacitors, in which case an input bypass is needed. A larger output capacitor can be added to improve transient response, the
adjustment terminal can be bypassed to achieve very high ripple rejection ratios which are difficult to achieve with standard 3-terminal
regulators.
Besides replacing fixed regulators, the WS337L is useful in a wide variety of other applications. Since the regulator is "floating" and sees
only the input-to-output differential is not exceeded.
Also, it makes an especially simple adjustable switching regulator, a programmable output regulator, or by connecting a fixed resistor
between the adjustment and output, the WS337L can be used as a precision current regulator. Supplies with electronic shutdown can be
achieved by clamping the adjustment terminal to ground that program the output to 1.2V where most loads draw little current.
The WS337L is available in a standard TO-92 transistor package and a SO-8 surface mount package. The WS337 is rated for operation
over a 0 to + 70 range.
FEATURES
Adjustable output down to 1.2V
Guaranteed 100mA output current
Line regulation typically 0.01%/V
Load regulation typically 0.1%
Current limit constant with temperature
Eliminates the need to stock many voltages
Standard 3-lead transistor package
80 dB ripple rejection
!
Output is short circuit protected
ELECTRICAL CHARACTERISTICS
1
Power dissipation
Internally Limited
Input-Output Voltage Differential
40v
Operating Junction
Temperature Range
0
to +70
Storage Temperature
55
to +150
Lead Temperature
Plastic Package (Soldiering 4 sec.)
260
ESD rating to be determined.
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNIT
ADJUSTMENT PIN CURRENT
50
100
A
ADJUSTMENT PIN CURRENT CHANGE
5mAI
OUT
100mA
3V|V
IN
-V
OUT
|
40V
0.2
5
A
REFERENCE VOLTAGE
3V|V
IN
-V
OUT
|
40V,
3
10mAI
OUT
100mA,P625MW
-1.3
-1.25
-1.2
V
LINE REGULATION
3V|V
IN
-V
OUT
|
40V
2
0.02
0.07
%/V
LOAD REGULATION
5mAI
OUT
100mA
2
0.3
1.5
%
TEMPERATURE STABILITY
T
MIN
T
J
T
MAX
0.65
%
|
V
IN
-V
OUT
|
40V
3.5
5
mA
MINIMUM LOAD CURRENT
3V|V
IN
-V
OUT
|
15V
2.2
3.5
mA
100
200
320
mA
CURRENT LIMIT
3V|V
IN
-V
OUT
|13V
|
V
IN
-V
OUT
|
=40V|
25
50
120
mA
RMS OUTPUT NOISE, % OF VOUT
T
A
=25, 10H
Z
-f-10KH
Z
0.03
%
65
dB
RIPPLE REJECTION RATIO
V
OUT
=-10V,F=120HZ, C
ADJ
=0
C
ADJ
=10F
66
80
dB
LONG-TERM STABILITY
T
A
=70
0.3
1
%
1
: Unless otherwise specified, these specifications apply 0 T
J
70 for the WS337L; V
IN
-V
OUT
= 5v and I
OUT
= 40mA. Although
power dissipation is internally limited, these specifications are applicable for power dissipation up to 625mW. I
MAX
is 100mA.
2
: Regulation is measured at constant junction temperature, using pulse testing with a low duty cycle. Changes in output voltage due to
heating effects are covered under the specification for thermal regulation.
3
: Thermal resistance of the TO-92 package is 180/W junction to ambient with 0.4" leads from a PC board and 160/W junction to
ambient with 0.125" lead length to PC board. The M package
JA
is 180/W in still air
Wing Shing Computer Components Co., (H.K.)Ltd.
Tel:(852)2341 9276 Fax:(852)2797 8153
Homepage:
http://www.wingshing.com
E-mail: wsccltd@hkstar.com
TO-92 WS337L
WS337L
3-TERMINAL ADJUSTABLE REGULATORS
INPUT
OUTPUT
ADJ
A
I
O
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