Texas Instruments PT79SR105H, PT79SR105S, PT79SR105V, PT79SR108H, PT79SR108S Datasheet

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22

Application Notes

Mechanical Outline

Product Selector Guide

Revised 5/15/98

PT79SR100 Series

-1.5 AMP NEGATIVE STEP-DOWN

INTEGRATED SWITCHING REGULATOR

• High Efficiency > 85%

• Self-Contained Inductor

• Short Circuit Protection

• Over-Temperature Protection

The PT79SR100 Series is a new

line of Negative Input/Negative Out-

put 3-terminal Integrated Switching

Regulators (ISRs). These ISRs have a

maximum output current of -1.5 Amps

and an output voltage that is laser

trimmed to most industry standard volt-

ages. They have excellent line and load

regulation, and are ideal for applications,

such as RS232 and Ethernet communica-

tions, ECL logic, and op-amp circuitry.

PT79SR1

COMCOM

-Vin

C1

1

23

C2D1

-Vout

Pin-Out Information

Pin Function

1 GND

2-V

in

3-V

out

Ordering Information

PT79SR1

XX

Y

Output Voltage

05 = -5.0 Volts

52 = -5.2 Volts

08 = -8.0 Volts

09 = -9.0 Volts

12 = -12.0 Volts

15 = -15.0 Volts

Package Suffix

V = Vertical Mount

S = Surface Mount

H = Horizontal

Mount

Standard Application

C1 = Optional ceramic (1µF)

C2 = Optional ceramic (1-5µF)

D1 = Zener diode required to clamp

turn-on overshoot

(See Application Note)

Specifications

Characteristics

PT79SR100 SERIES

(T

a

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

Output Current I

o

Over V

in

range -0.1* — -1.5 A

Short Circuit Current I

sc

V

in

=V

o

-4V — -3.5 — Apk

Input Voltage Range V

in

I

o

=-0.1 to -1.5 A V

o

=-5V -9 — -30 V

-0.1 ≥ I

o

≥ -1.5 A V

o

=-15V -19 — -30 V

Output Voltage Tolerance ∆V

o

Over Vin range, I

o

=-1.5 A

— ±1.0 ±3.0 %V

o

T

a

=-20°C to shutdown

Line Regulation Reg

line

Over V

in

range — ±1.0 ±2.0 %V

o

Load Regulation Reg

load

-0.1 ≤ I

o

≤ -1.5 A — ±0.5 ±1.0 %V

o

V

o

Ripple/Noise V

n

V

in

=-15V, I

o

=-1.0 A,V

o

=-5V — 35 — mV

pp

Transient Response t

tr

50% load change — 100 — µSec

V

o

=overshoot/undershoot — 30 — %V

o

Efficiency η V

in

=-10V, I

o

=-1.0A, V

o

=-5V — 85 — %

Switching Frequency ƒ

o

Over V

in

and I

o

ranges 0.95 1.0 1.05 MHz

Absolute Maximum T

a

-40 — +85 °C

Operating Temperature Range

Recommended Operating T

a

Free Air Convection, (40-60LFM)

-40 — +60** °C

Temperature Range Over V

in

and I

o

ranges

Thermal Resistance θ

ja

Free Air Convection, (40-60LFM) — 45 — °C/W

Temperature Coefficient T

c

Over V

in

and I

o

ranges — ±0.5 ±1.5 mV/°C

Storage Temperature T

s

— -40 — +125 °C

Mechanical Shock — Per Mil-STD-883D, Method 2002.3 — 500 — G’s

Mechanical Vibration — Per Mil-STD-883D, Method 2007.2,

—5

—

G’s

20-2000 Hz, soldered in a PC board

Weight — — — 7.0 — Grams

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

Pkg Style 500