Datasheet SC431CZ-2TA, SC431CZ-2TR, SC431CS-0.5TR, SC431CS-1TR, SC431CS-2TR Datasheet (Semtech Corporation)

SC431

© 1998 SEMTECH CORP. 652 MITCHELL ROAD NEWBURY PARK CA 91320

ADJUSTABLE SHUNT REGULATOR

April 13, 1998

1

BLOCK DIAGRAMPIN CONFIGURATIONS

DESCRIPTION

The SC431 is a three terminal adjustable shunt regula­tor with thermal stability guaranteed over temperature.
The output voltage can be adjusted to any value from

2.5V (V

REF

) to 36V with two external resistors. The

SC431 has a typical dynamic output impedance of

0.25Ω. Active output circuitry provides a very sharp
turn on characteristic, making the SC431 an excellent
replacement for zener diodes.

The SC431 shunt regulator is available in three voltage
tolerances (0.5%, 1.0% and 2.0%) and three package
options (SOT-23-3, SO-8 and TO-92). The three volt­age tolerances allow the designer the opportunity to
select the proper cost/tolerance for their application.

FEATURES

•

Wide operating current range 100µA to 150mA

•

Low dynamic output impedance 0.25 Ω typ.

•

Trimmed bandgap design + 0.5%

•

Alternate for TL431, LM431 & AS431

APPLICATIONS

•

Linear Regulators

•

Adjustable Supplies

•

Switching Power Supplies

•

Battery Operated Computers

•

Instrumentation

•

Computer Disk Drives

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SOT-23 -3 Lead (Top View)

SOIC 8 Lead (Top View)

TO-92 (Top View)

SYMBOL DIAGRAM

SC431

© 1998 SEMTECH CORP. 652 MITCHELL ROAD NEWBURY PARK CA 91320

ADJUSTABLE SHUNT REGULATOR

April 13, 1998

2

Parameter Symbol Maximum Units

Cathode Voltage V

Z

37 V

Continous Cathode Current I

Z

150 mA

Reference Input Current I

REF

10 mA

Operating Junction Temperature Range T

J

-40 to +150 °C

Storage Temperature Range T

STG

-65 to +150 °C

Thermal Resistance
TO-92
SO-8
SOT-23

θ

JA

160
175
410

°C/W

Power Dissipation at T

A

= 25°C
TO-92
SO-8
SOT-23

P

D

0.78

0.71

0.30

W

Lead Temperature (Soldering) 10 seconds T

LEAD

260 °C

ABSOLUTE MAXIMUM RATINGS

PACKAGE TOLERANCE

0.5% 1.0% 2.0% T/R Quantity

SO-8

(1)

SC431CS - .5 SC431CS - 1 SC431CS - 2 2.5K

SOT-23

(1)

SC431CSK - .5 SC431CSK - 1 SC431CSK - 2 3K

TO-92

(1)(2)

SC431CZ - .5 SC431CZ - 1 SC431CZ - 2 TR=3K, TA=2K

Notes:
(1) Add suffix ‘TR’ for Tape & Reel.
(2) Add suffix ‘TA’ for Tape Ammo.

ORDERING INFORMATION

SC431

© 1998 SEMTECH CORP. 652 MITCHELL ROAD NEWBURY PARK CA 91320

ADJUSTABLE SHUNT REGULATOR

April 13, 1998

3

SC431 0.5% SC431 1% SC431 2%

Parameter Symbol Condition MIN TYP MAX MIN TYP MAX MIN TYP MAX UNITS

Reference Voltage V

REF

VZ = V

REF TA

= 25°C

I

Z

= 10mA

(test circuit 1)

2.482 2.495 2.507 2.470 2.495 2.520 2.445 2.495 2.545 V

V

REF

Temp Deviation V

DEV

TA = -40 to +85°C, VZ = V

REF

(test circuit 1) IZ = 10mA

8 17 8 25 15 30 mV

Ratio of Change in
V

REF

to Change in

Cathode Voltage

I

Z

= 10mA, ∆VZ = 10V to V

REF

-0.5 -2.7 -0.5 -2.7 -0.5 -2.7
mV/V

I

Z

= 10mA, ∆VZ = 36V to 10V

-1.0 -2.0 -1.0 -2.0 -1.0 -2.0

Reference Input
Current

I

REF

R1 = 10k

Ω,

R2 =

∞,

IZ = 10mA

(test circuit 2)

0.5 4 0.5 4 0.5 4 µA

I

REF

Temp Deviation I

REF(DEV)

TA = -40 to +85°C,

R1 = 10kΩ, R2 =

∞,

IZ =10mA

(test circuit 2)

0.4 1.2 0.4 1.2 0.4 1.2 µA

Off State Cathode
Current

I

Z (off)

V

REF

= 0V, VZ = 36V

(test circuit 3)

0.04 0.5 0.04 0.5 0.04 0.5 µA

Dynamic Output
Impedance

r

Z

f < 1kHz, VZ = V

REF

IZ = 100uA to 100mA

(test circuit 1)

0.25 0.5 0.25 0.5 0.25 0.5

Ω

Minimum Operating
Current

I

Z (min)

VZ = V

REF

(test circuit 1)

100 100 100 µA

RECOMMENDED OPERATING CONDITIONS

Min Max Symbol

Cathode Voltage, V

Z

V

REF

36 V

Cathode Current, I

Z

0.1 150 mA

TEST CIRCUITS

Test Circuit 1:

V

Z

= V

REF

Test Circuit 2:

V

Z

> V

REF

Test Circuit 3:

Off State Current

Z

REF

V

V

∆

∆

ELECTRICAL CHARACTERISTICS

Unless specified, TA = 25°C

SC431

© 1998 SEMTECH CORP. 652 MITCHELL ROAD NEWBURY PARK CA 91320

ADJUSTABLE SHUNT REGULATOR

April 13, 1998

4

TYPICAL CHARACTERISTICS

-300

-200

-100

0

100

200

300

-2-10123

V

Z

(V)

I

Z

(

µ

µµ

µ

A)

VZ = V

REF

TA = 25 oC

Cathode Current vs. Cathode Voltage

-150

-100

-50

0

50

100

150

-2-10123

V

Z

(V)

I

Z

(mA)

VZ = V

REF

TA = 25 oC

Cathode Current vs. Cathode Voltage

0

20

40

60

80

100

-50-250 255075100125150

T

J

(°C)

I

REF

(nA)

IZ = 10mA
R1 = 10k

Ω

R2 =

∞

Reference Input Current vs.

Junction Temperature

0

0.1

0.2

0.3

0.4

0.5

-50-250 255075100125150

T

J

(°C)

∆

∆∆

∆

V

REF

/

∆

∆∆

∆

V

Z

(-mV/V)

IZ = 10mA

∆

VZ = 3V to 36V

Ratio of Delta Reference Voltage to Delta

Cathode Voltage vs. Junction Temperature

0.001

0.01

0.1

1

10

100

-50 -25 0 25 50 75 100 125 150

T

J

(°C)

I

Z(off)

VZ = 36V
V

REF

= 0V

Off-State Cathode Current

vs. Junction Temperature

2.485

2.490

2.495

2.500

2.505

2.510

2.515

-50 -25 0 25 50 75 100 125 150

T

J

(°C)

V

REF

(V)

VZ = V

REF

IZ = 10mA

Reference Voltage vs.

Junction Temperature

SC431

© 1998 SEMTECH CORP. 652 MITCHELL ROAD NEWBURY PARK CA 91320

ADJUSTABLE SHUNT REGULATOR

April 13, 1998

5

TYPICAL CHARACTERISTICS (Cont.)

Test Circuit For Small-Signal

Gain and Phase Shift

APPLICATION CIRCUIT

Notes for Application Circuit:

1) Set V

OUT

according to the following equation:

2) Choose the value for R as follows:

• The maximum limit for R should be such that the
cathode current, I

Z

, is greater than the minimum

operating current (100µA) at V

IN(min)

.

• The minimum limit for R should be such that I

Z

does not exceed 150mA under all load conditions,
and the instantaneous turn-on value for I

Z

does not
exceed 200mA. Both of the following conditions
must be met:

(to limit instantaneous turn-on I

Z

)

(to limit I

Z

under normal

operating conditions)

1RI

2R

1R

1VV

REFREFOUT

+











+=

mA200

V

R

(max)IN

min

≥

mA150I

VV

R

(min)OUT

OUT(max)IN

min

+

−

≥

-20

-10

0

10

20

30

40

50

60

70

80

1.0E+02 1.0E+03 1.0E+04 1.0E+05 1.0E+06

f (Hz)

A

V

(dB)

-630

-585

-540

-495

-450

-405

-360

-315

-270

-225

-180

Phase Shift (deg)

IZ = 10mA
T

A

= 25°C

Small-Signal Gain and Phase Shift

vs. Frequency

0.01

0.1

1

10

100

1.0E+03 1.0E+04 1.0E+05 1.0E+06 1.0E+07

f (Hz)

r

Z

(

Ω

ΩΩ

Ω

)

IZ = 10mA
T

A

= 25°C

Reference Impedance

vs. Frequency

SC431

© 1998 SEMTECH CORP. 652 MITCHELL ROAD NEWBURY PARK CA 91320

ADJUSTABLE SHUNT REGULATOR

April 13, 1998

6

OUTLINE DRAWING SOT-23

OUTLINE DRAWING SO-8

OUTLINE DRAWING TO-92