Micropac Industries cannot assume any responsibility for any circuits shown or represent that they are free from patent infringement.

Micropac reserves the right to make changes at any time in order to improve design and to supply the best product possible.

MICROPAC INDUSTRIES, INC. HYBRID MICROELECTRONICS PRODUCTS DIVISION

• 905 E. Walnut St., Garland, TX 75040 • (972) 272-3571 • Fax (972) 494-2281

www.micropac.com

12/12/01

2

52149/52174

NEGATIVE ADJUSTABLE 5-AMP, VOLTAGE REGULATOR

ELECTRICAL CHARACTERISTICS

PARAMETER

TEST CONDITIONS

MIN

TYP

MAX

UNIT

Output Voltage Range

-7.0

-35

V

Nominal Output Voltage Range

2.55

24

V

Output Voltage Tolerance

40V

4

Line Regulation

40V

0.4

1.0

Load Regulation

-10mA

0.7

1.0

Control Pin Current

3.0

µA

Quiescent Current

7.0

mA

Ripple Rejection

-18V

50

dB

Output Noise Voltage

200

µV

Dropout Voltage

-2.2

V

Short-Circuit Current Limit

8

12

A

Control Pin voltage (Reference)

-2.65

-2.45

V

DESIGN CONSIDERATIONS

This device has thermal overload protection from excessive power and internal short circuit protection, which limits the circuit’s maximum

current. Thus, the device is protected from overload abnormalities. Although the internal power dissipation is limited, the junction

temperature must be kept below the maximum specified temperature (150ºC). It is recommended, by the manufacturer, that the maximum

junction temperature be kept as low as possible for increased reliability. To calculate the maximum junction temperature or heat sink

required, the following thermal resistance values should be used.

Package

Typical

Max

TO-3

1.8

2.5

Where:

The device is designed to operate without external compensation components. However, the amount of external filtering of these voltage

regulators depends upon the circuit layout. If in a specific application the regulator is more than four inches from the filter capacitor, a 2

µF

solid tantalum capacitor should be used at the input. A 1

µF capacitor should be used at the output to reduce transients created by fast

switching loads, as seen in the basic test circuit. These filter capacitors must be located as close to the regulator as possible.

Caution: Permanent damage can result from forcing the output voltage higher than the input voltage. A protection diode from output to

input should be used if this condition exists.

VOLTAGE OUTPUT

The device has an adjustable output voltage from -2.55 to -24V which can be programmed by the external resistor network (potentiometer

or two fixed resistors) using the relationship:

Example:

If R1 = 0

Ω and R2 = 5kΩ, Then

R2

or, if R1 = 12.8 k

Ω and R2 = 2.1 kΩ then