Texas Instruments PT78ST212V Datasheet

For assistance or to order, call [phone]

PT78ST200 Series

12V 2 AMP POSITIVE STEP-DOWN
INTEGRATED SWITCHING REGULATOR

Application Notes

Mechanical Outline

Product Selector Guide

Revised 5/15/98

Standard Application

Vin

1

PT78ST200

C1

C1 = Optional 1µF ceramic
C2 = Required 100µF electrolytic

• High Efficiency > 87%

• Wide Input Range

• Aluminum Heatsink for

Applications with Airflow

• Self-Contained Inductor

• Short Circuit Protection

• Over-Temperature Protection

• Pin Compatible with Linear

The Power Trends’ PT78ST200 is
a new 3-terminal Integrated Switching
Regulator (ISR) that can supply up to 24
watts of regulated 12V power. With a
surge capability of 3 Amps and an out­put voltage that is laser trimmed, it is
ideal for inductive load applications
such as disk drive motors.

3-Terminal, “78” Series Regulators

• Small Footprint

Pin-Out Information

Pin Function

V

1

in

2 GND

V

3

out

Vout

3

C2

+

COMCOM

2

Ordering Information

PT78ST2

Output Voltage

12 = 12.0 Volts

XX Y

Package Suffix

V = Vertical Mount

Specifications

Characteristics
(Ta = 25°C unless noted) Symbols Conditions Min Typ Max Units

Output Current I

Short Circuit Current I
Input Voltage Range V

Output Voltage Tolerance ∆V

Line Regulation Reg
Load Regulation Regload 0.1 ≤ Io ≤ 2.0A — ±0.2 ±0.4 %V
V

Ripple/Noise V

o

Transient Response t
(with 100µF output cap) Vo over/undershoot — 5.0 — %V

Efficiency η Vin=17V, Io=2.0A — 87 — %
Switching Frequency ƒ
Absolute Maximum T

Operating Temperature Range
Recommended Operating T

Temperature Range at Vin= 24V, Io=2A
Thermal Resistance θja Free Air Convection, (40-60LFM) — 35 — °C/W
Storage Temperature T
Mechanical Shock — Per Mil-STD-883D, Method 2002.3 — 500 — G’s
Mechanical Vibration — Per Mil-STD-883D, Method 2007.2,

Weight — — — 11 — Grams

*ISR will operate down to no load with reduced specifications. **See Thermal Derating chart.

Note:

The PT78ST200 Series requires a 100µF electrolytic or tantalum output capacitor for proper operation in all applications.

o

sc

in

o

line

n

tr

o

a

a

s

Over Vin range
With forced air cooling

Vin = V

min — 5.0 — Apk

in

0.1 ≤ Io ≤ 2.0A 16 — 28 V
Over Vin range, Io= 2.0A

Ta= 0°C to +60°C
Over Vin range — ±0.4 ±0.8 %V

Vin=17V, Io=2.0A, Vo=12V — 120 — mV
50% load change — 100 — µSec

Over Vin and Io ranges 0.95 1.0 1.05 MHz
— -40 — +65 °C

Free Air Convection, (40-60LFM)

— -40 — +125 °C

20-2000 Hz, Soldered in a PC board

Pkg Style 600

PT78ST200 SERIES

0.1* — 2.0 A

— ±1.0 ±2.0 %Vo

-40 — +55** °C

—10

—

o

o

pp

o

G’s

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Power Trends, Inc. 27715 Diehl Road, Warrenville, IL 60555 [phone] Fax: [phone] http://www.powertrends.com

CHARACTERISTIC DATA

PT78ST212 12.0 VDC (See Note 1)

Efficiency vs Output Current

100

90

80

70

Efficiency - %Ripple-(mV)Iout-(Amps)PD-(Watts)

60

50

40

00.511.52

Iout-(Amps)

Ripple vs Output Current

100

For assistance or to order, call [phone]

PT78ST200 Series

Vin

16.0V

18.0V

21.0V

24.0V

28.0V

Wide Input Range Products

DATA SHEETS

80

60

40

20

0

0 0.25 0.5 0.75 1 1.25 1.5 1.75 2

Iout-(Amps)

Thermal Derating (Ta) (See Note 2)

2

1.8

1.6

1.4

1.2

1

0.8

0.6

0.4

0.2

0

16 18 20 22 24 26 28

Vin-(Volts)

45°C

65°C

Power Dissipation vs Output Current

3.5

3

2.5

2

1.5

1

0.5

0

0 0.5 1 1.5 2

`

Iout-(Amps)

55°C

Vin

28.0V

24.0V

21.0V

18.0V

16.0V

Vin

28.0V

24.0V

21.0V

18.0V

16.0V

Note 1: All data listed in the above graphs, except for derating data, has been developed from actual products tested at 25°C. This data is considered typical data for the ISR.
Note 2: Thermal derating graphs are developed in free air convection cooling of 40-60 LFM. (See Thermal Application Notes.)

Power Trends, Inc. 27715 Diehl Road, Warrenville, IL 60555 [phone] Fax: [phone] http://www.powertrends.com

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