TI PT78ST212V

For assistance or to order, call
Application Notes
Mechanical Outline
Product Selector Guide
(800) 531-5782
PT78ST200 S e r i e s
12V 2 AMP POSITIVE STEP-DOWN
INTEGRATED SWITCHING REGULATOR
Standard Application
• 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
3-Terminal, “78” Series Regulators
• Small Footprint
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.
Pin-Out Information
Ordering Information
Pin
Function
1
Vin
2
GND
Vout
3
Vin
1
PT78ST200
C1
2
PT78ST2 XX
Y
Output Voltage
Package Suffix
12 = 12.0 Volts
V = Vertical Mount
Vout
3
C2
Revised 5/15/98
+
COM
COM
C1 = Optional 1µF ceramic
C2 = Required 100µF electrolytic
Pkg Style 600
Specifications
PT78ST200 SERIES
Characteristics
(Ta = 25°C unless noted)
Symbols
Conditions
Min
Typ
Max
Units
Output Current
Io
Over Vin range
With forced air cooling
0.1*
—
2.0
A
Short Circuit Current
Isc
Vin = Vin min
—
5.0
—
Apk
Input Voltage Range
Output Voltage Tolerance
Vin
∆Vo
0.1 ≤ Io ≤ 2.0A
Over Vin range, Io= 2.0A
Ta= 0°C to +60°C
16
—
28
V
—
±1.0
±2.0
%Vo
Line Regulation
Regline
Over Vin range
—
±0.4
±0.8
%Vo
Load Regulation
Regload
0.1 ≤ Io ≤ 2.0A
—
±0.2
±0.4
%Vo
Vo Ripple/Noise
Vn
Vin=17V, Io=2.0A, Vo=12V
—
120
—
mVpp
Transient Response
(with 100µF output cap)
ttr
50% load change
Vo over/undershoot
—
—
100
5.0
—
—
µSec
%Vo
Efficiency
η
Vin=17V, Io=2.0A
—
87
—
%
Switching Frequency
ƒo
Over Vin and Io ranges
0.95
1.0
1.05
MHz
Absolute Maximum
Operating Temperature Range
Ta
—
-40
—
+65
°C
Recommended Operating
Temperature Range
Ta
Free Air Convection, (40-60LFM)
at Vin= 24V, Io=2A
-40
—
+55**
°C
Thermal Resistance
θja
Free Air Convection, (40-60LFM)
—
35
—
°C/W
Storage Temperature
Ts
—
-40
—
+125
°C
Mechanical Shock
—
Per Mil-STD-883D, Method 2002.3
—
500
—
G’s
Mechanical Vibration
—
Per Mil-STD-883D, Method 2007.2,
20-2000 Hz, Soldered in a PC board
—
10
—
G’s
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.
18
Power Trends, Inc. 27715 Diehl Road, Warrenville, IL 60555 (800) 531-5782 Fax: (630) 393-6902 http://www.powertrends.com
For assistance or to order, call
(800) 531-5782
PT78ST200 S e r i e s
CHARACTERISTIC
DATA
Efficiency vs Output Current
100
Efficiency - %
90
Vin
80
16.0V
18.0V
21.0V
24.0V
28.0V
70
60
50
40
0
0.5
1
1.5
2
Iout-(Amps)
Ripple vs Output Current
100
Ripple-(mV)
80
Vin
28.0V
24.0V
21.0V
18.0V
16.0V
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)
45°C
2
1.8
55°C
65°C
1.6
Iout-(Amps)
1.4
1.2
1
0.8
0.6
0.4
0.2
0
16
18
20
22
24
26
28
Vin-(Volts)
Power Dissipation vs Output Current
3.5
3
PD-(Watts)
2.5
Vin
28.0V
24.0V
21.0V
18.0V
16.0V
2
`
1.5
1
0.5
0
0
0.5
1
1.5
2
Iout-(Amps)
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 (800) 531-5782 Fax: (630) 393-6902 http://www.powertrends.com
19
DATA SHEETS
(See Note 1)
Wide Input Range Products
PT78ST212 12.0 VDC
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