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 μF 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

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

μ

A

ADJUSTMENT PIN CURRENT CHANGE

5mA≦I

3V≦|V

0.2

5

μ

A

REFERENCE VOLTAGE

3V≦|V

3

10mA≦I

-1.3

-1.25

-1.2

V

LINE REGULATION

3V≦|V

2

0.02

0.07

%/V

LOAD REGULATION

5mA≦I

2

0.3

1.5

%

TEMPERATURE STABILITY

T

0.65

%

|

V

3.5

5

mA

MINIMUM LOAD CURRENT

3V≦|V

2.2

3.5

mA

100

200

320

mA

CURRENT LIMIT

3V≦|V

|

V

25

50

120

mA

RMS OUTPUT NOISE, % OF VOUT

T

0.03

%

65

dB

RIPPLE REJECTION RATIO

V

C

66

80

dB

LONG-TERM STABILITY

T

0.3

1

%

: 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.

: 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

Wing Shing Computer Components Co., (H.K.)Ltd.

Tel:(852)2341 9276

Fax:(852)2797 8153

E-mail:

wsccltd@hkstar.com

TO-92 WS337L

WS337L

3-TERMINAL ADJUSTABLE REGULATORS

INPUT

OUTPUT

ADJ

A

I

O