TI SLTS060A

PT78ST200 Series
12V 2 Amp Positive Step-Down
Integrated Switching Regulator
SLTS060A
(Revised 6/30/2000)
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 series of 3-terminal Integrated
Switching Regulators (ISRs) 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
Y
Output Voltage
Package Suffix
12 = 12.0 Volts
V = Vertical Mount
Vout
3
C2
PT78ST2 XX
+
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.
For technical support and more information, see inside back cover or visit www.ti.com/powertrends
Typical Characteristics
PT78ST200 Series
12V 2 Amp Positive Step-Down
Integrated Switching Regulator
PT78ST212 12.0 VDC
(See Note 1)
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.)
For technical support and more information, see inside back cover or visit www.ti.com/powertrends
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