For assistance or to order, call
(800) 531-5782
Power Trends, Inc.
27715 Diehl Road, Warrenville, IL 60555
(800) 531-5782
Fax: (630) 393-6902 http://www.powertrends.com
3 AMP POSITIVE STEP-DOWN
INTEGRATED SWITCHING REGULATOR
7 8 S T 3 0 0
S e r i e s
Standard Application
C1 = Optional 1F ceramic
C2
= Required 100F electrolytic
Pin-Out Information
Pin No. Function
1
V
i
n
2
GND
3
V
out
Ordering Information
78ST3 C
Output Voltage
XX
Y
05
= 5.0 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 78ST300 is a series of wide
input voltage, 3 terminal Integrated
Switching Regulators (ISRs). Employ-
ing a ceramic substrate, these ISRs
have a maximum output current of 3A.
The output voltage is laser trimmed
for high accuracy.
The 78ST300 series regulators
have internal short-circuit and over-
temperature protection and may be
used in a wide variety of applications.
Specifications
Characteristics
78ST300 SERIES
(T
a
= 25C 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
8
--
20
V
Output Voltage Tolerance
V
o
Over V
in
range
--
1.0
2.0
%Vo
T
a
= 0C to +60C
Line Regulation
Reg
line
Over V
in
range
--
0.4
0.8
%V
o
Load Regulation
Reg
load
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
--
Sec
(with 100F output cap)
V
o
over/undershoot
5.0
%V
o
Efficiency
V
in
= 9V, I
o
= 3.0A
--
80
--
%
Switching Frequency
o
Over V
in
and I
o
ranges
0.95
1.0
1.05
MHz
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
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 78ST300 Series requires a 100F electrolytic or tantalum output capacitor for proper operation in all applications.
78ST300
C2
+
Vout
GND
GND
Vin
C1
1
2
3
(For dimensions and PC board
layout see Package Style 600.)
Revised 6/30/98
For assistance or to order, call
(800) 531-5782
Power Trends, Inc.
27715 Diehl Road, Warrenville, IL 60555
(800) 531-5782
Fax: (630) 393-6902 http://www.powertrends.com
C H A R A C T E R I S T I C D A T A
Note 1:
All data listed in the above graphs, except for derating data, has been developed from actual products tested at 25C. 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)
78ST305_ 5.0 VDC
(See Note 1)
Efficiency vs Output Current
Ripple vs Output Current
Power Dissipation vs Output Current
Efficiency (%)
Ripple (mV)
PD (Watts)
Iout (A)
Iout (A)
Iout (A)
7 8 S T 3 0 0
S e r i e s
Vin
Vin
Vin
40
50
60
70
80
90
100
0.0
0.5
1.0
1.5
2.0
2.5
3.0
7.5V
9.0V
12.0V
15.0V
20.0V
0
5
10
15
20
25
30
35
40
0.0
0.5
1.0
1.5
2.0
2.5
3.0
7.5V
9.0V
12.0V
15.0V
20.0V
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
0.0
0.5
1.0
1.5
2.0
2.5
3.0
7.5V
9.0V
12.0V
15.0V
20.0V
Thermal Derating (T
a
)
(See Note 2)
Iout (A)
Vin (Volts)
0.0
0.5
1.0
1.5
2.0
2.5
3.0
8
10
12
14
16
18
20
85C
70C
60C
50C
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1999, Texas Instruments Incorporated
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