Texas Instruments 78HT305VC, 78HT305HC Datasheet
For assistance or to order, call (800) 531-5782
78HT300 Series
3 AMP POSITIVE STEP-DOWN
INTEGRATED SWITCHING REGULATOR
Revised 6/30/98
Standard Application
Vin
C1
1
78HT300
C1 = Optional 1µF ceramic
C2 = Required 100µF electrolytic
• 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). Employing a ceramic substrate, these
ISRs have a maximum output current
of 3A. The output voltage is lasertrimmed for high accuracy.
The 78HT300 series regulators
have internal short-circuit and overtemperature protection and may be
used in a wide variety of applications.
Pin-Out Information
Pin No. Function
1V
in
2 GND
3
2
C2
Vout
+
GNDGND
3V
out
Ordering Information
78HT3 C
Output Voltage
05 = 5.0 Volts
53 = 5.25 Volts
(For dimensions and PC board
layout see Package Style 600.)
Y
XX
Package Suffix
V = Vertical Mount
H = Horizontal
Mount
Specifications
Characteristics
(Ta = 25°C unless noted) Symbols Conditions Min Typ Max Units
Output Current I
Input Voltage Range V
Output Voltage Tolerance ∆V
Line Regulation Reg
Load Regulation Regload 0.1 ≤ Io ≤ 3.0A — ±0.2 ±0.4 %V
Ripple/Noise V
Transient Response t
(with 100µF output cap) Vo over/undershoot 5.0 %V
Efficiency η V
Switching Frequency ƒ
Absolute Maximum T
Operating Temperature Range
Recommended Operating T
Temperature Range Over Vin and Io ranges
Thermal Resistance θ
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 78HT300 Series requires a 100µF electrolytic or tantalum output capacitor for proper operation in all applications.
o
in
o
line
n
tr
o
a
a
ja
s
Over Vin range 0.1* — 3.0 A
Io = 0.1 to 3.0A Vo+3 — 28 V
Over Vin range
Ta = 0°C to +60°C
Over Vin range — ±0.4 ±0.8 %V
Vin = V
min, I
= 3.0A — 1 — %Vo
in
o
50% load change — 100 — µSec
= 9V, Io = 3.0A — 80 — %
in
Over Vin and Io ranges 700 750 800 kHz
— -40 — +70 °C
Free Air Convection, (40-60LFM)
Free Air Convection, (40-60LFM) — 35 — °C/W
— -40 — +125 °C
20-2000 Hz, soldered in a PC board
78HT300 SERIES
— ±1.0 ±2.0 %Vo
-40 — +70** °C
—10—G’s
o
o
o
Power Trends, Inc. 27715 Diehl Road, Warrenville, IL 60555 (800) 531-5782 Fax: (630) 393-6902 http://www.powertrends.com
CHARACTERISTIC DATA
78HT305_ 5.0 VDC
(See Note 1)
Efficiency vs Output Current
100
90
80
70
Efficiency (%)Ripple (mV)PD (Watts)
60
50
40
0.0 0.5 1.0 1.5 2.0 2.5 3.0
Iout (A)
Ripple vs Output Current
60
50
40
30
20
10
0
0.0 0.5 1.0 1.5 2.0 2.5 3.0
Iout (A)
For assistance or to order, call (800) 531-5782
78HT300 Series
Vin
8.0V
10.0V
15.0V
20.0V
28.0V
Vin
8.0V
10.0V
15.0V
20.0V
28.0V
Thermal Derating (Ta) (See Note 2)
3.0
2.5
2.0
1.5
Iout (A)
1.0
0.5
0.0
8 1216202428
Vin (Volts)
60°C
70°C
85°C
50°C
Power Dissipation vs Output Current
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0.0
0.0 0.5 1.0 1.5 2.0 2.5 3.0
Iout (A)
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 Note)
Vin
8.0V
10.0V
15.0V
20.0V
28.0V
Power Trends, Inc. 27715 Diehl Road, Warrenville, IL 60555 (800) 531-5782 Fax: (630) 393-6902 http://www.powertrends.com
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