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3 AMP POSITIVE STEP-DOWN
INTEGRATED SWITCHING REGULATOR
78HT300 Series
Standard Application
C1 = Optional 1µF ceramic
C2
= Required 100µF electrolytic
Pin-Out Information
Pin No. Function
1V
in
2 GND
3V
out
Ordering Information
78HT3 C
Output Voltage
XX
Y
05 = 5.0 Volts
53 = 5.25 Volts
Package Suffix
V = Vertical Mount
H = Horizontal
Mount
• High Efficiency > 80%
• Wide Input Range
• Self-Contained Inductor
• Short-Circuit Protection
• Over-Temperature Protection
• Fast Transient Response
The 78HT300 is a series of wide
input voltage, 3 terminal Integrated
Switching Regulators (ISRs). Em-
ploying a ceramic substrate, these
ISRs have a maximum output current
of 3A. The output voltage is laser-
trimmed for high accuracy.
The 78HT300 series regulators
have internal short-circuit and over-
temperature protection and may be
used in a wide variety of applications.
Specifications
Characteristics
78HT300 SERIES
(T
a
= 25°C unless noted) Symbols Conditions Min Typ Max Units
Output Current I
o
Over V
in
range 0.1* — 3.0 A
Input Voltage Range V
in
I
o
= 0.1 to 3.0A V
o
+3 — 28 V
Output Voltage Tolerance ∆V
o
Over V
in
range
— ±1.0 ±2.0 %Vo
T
a
= 0°C to +60°C
Line Regulation Reg
line
Over V
in
range — ±0.4 ±0.8 %V
o
Load Regulation Regload 0.1 ≤ I
o
≤ 3.0A — ±0.2 ±0.4 %V
o
Ripple/Noise V
n
V
in
= V
in
min, I
o
= 3.0A — 1 — %Vo
Transient Response t
tr
50% load change — 100 — µSec
(with 100µF output cap) V
o
over/undershoot 5.0 %V
o
Efficiency η V
in
= 9V, I
o
= 3.0A — 80 — %
Switching Frequency ƒ
o
Over V
in
and I
o
ranges 700 750 800 kHz
Absolute Maximum T
a
— -40 — +70 °C
Operating Temperature Range
Recommended Operating T
a
Free Air Convection, (40-60LFM)
-40 — +70** °C
Temperature Range Over V
in
and I
o
ranges
Thermal Resistance θ
ja
Free Air Convection, (40-60LFM) — 35 — °C/W
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,
—10—G’s
20-2000 Hz, soldered in a PC board
Weight — — — 11 — Grams
* ISR will operate down to no load with reduced specifications.
** See Thermal Derating chart.
Note:
The 78HT300 Series requires a 100µF electrolytic or tantalum output capacitor for proper operation in all applications.
78HT300
C2
+
Vout
GNDGND
Vin
C1
1
2
3
(For dimensions and PC board
layout see Package Style 600.)
Revised 6/30/98
