Texas Instrumentʼs PT78NR112 creates a negative output voltage from +12Vdc
input. These easy-to-use, 3-terminal, Integrated Switching Regulators have
maximum output power of 5 watts and a negative output voltage that is laser
trimmed. They also have excellent line and load regulation. They can be used
with current sensors that reguire ±12Vdc power supplies. (www.ti.com)
PT78NR100 Series
1 Amp Plus to Minus Voltage
Integrated Switching Regulator
SLTS058B
(Revised 8/31/2000)
•
•
•
•
•
•
Negative output from positive input
Wide Input Range
Self-Contained Inductor
Short Circuit Protection
Over-Temperature Protection
Fast Transient Response
The PT78NR100 Series creates a
negative output voltage from a posi-
tive input voltage greater than 7V.
These easy-to-use, 3-terminal, Inte-
grated Switching Regulators (ISRs)
have maximum output power of 5
watts and a negative output voltage
that is laser trimmed. They also have
excellent line and load regulation.
Pin-Out Information
Pin
1
Ordering Information
Function
+V
i
n
-V
out
GND
PT78NR1
XX
Output Voltage
03
= -3.0 Volts
05
= -5.0 Volts
52
= -5.2 Volts
06
= -6.0 Volts
07
= -7.0 Volts
08
= -8.0 Volts
09
= -9.0 Volts
10
= -10.0 Volts
12
= -12.0 Volts
14
= -13.9 Volts
15
= -15.0 Volts
PT78NR100 SERIES
Y
Package Suffix
V
= Vertical Mount
S
= Surface Mount
H
= Horizontal
Mount
Standard Application
Vin
+
1
2
3
2
PT78NR100
3
-Vout
C1
COM
C2
+
COM
C1 = Required 100µF electrolytic
(1)
C2 = Required 100µF electrolytic
(1)
Specifications
Characteristics
(T
a
= 25°C unless noted)
Output Current
Symbols
I
o
Conditions
Pkg Style 500
Min
V
o
=-5V
V
o
=-6V
V
o
=-7, -8, -9V
V
o
=-10V
V
o
=-12V
V
o
=-13.9, -15V
0.05
(2)
0.05
(2)
0.05
(2)
0.05
(2)
0.05
(2)
0.05
(2)
—
—
—
V
o
=-5V
V
o
=-6, -7, -8, -9V
V
o
=-10, -12V
V
o
=-13.9, -15V
7
7
7
7
—
—
—
—
—
—
—
600
-40
—
-40
—
—
—
Typ
—
—
—
—
—
—
4×I
max
4
0.5
—
—
—
—
±1.0
±0.5
±0.5
±2
100
5.0
75
650
—
45
—
500
5
6.5
Max
1.00
0.8
0.55
0.5
0.40
0.30
—
—
—
25
21
18
15
±3.0
±1.0
±1.0
—
250
—
—
700
+85
(3)
—
+125
—
—
Units
Over V
in
range
A
Short Circuit Current
Inrush Current
Input Voltage Range
I
sc
I
ir
t
ir
V
in
V
in
=10V
V
in
=10V
On start-up
0.1
≤
I
o
≤
I
max
Apk
A
mSec
V
V
V
V
%V
o
%V
o
%V
o
%V
o
µSec
%V
o
%
kHz
°C
°C/W
°C
G’s
G’s
Grams
Output Voltage Tolerance
Line Regulation
Load Regulation
V
o
Ripple/Noise
Transient Response
(with 100µF output cap)
Efficiency
Switching Frequency
Absolute Maximum
Operating Temperaturte Range
Thermal Resistance
Storage Temperature
Mechanical Shock
Mechanical Vibration
Weight
∆V
o
Reg
line
Reg
load
V
n
t
tr
η
ƒ
o
T
a
Over V
in
range
T
a
=-20°C to +70°C
Over V
in
range
0.1
≤
I
o
≤
I
max
V
in
=10V, I
o
=I
max
50% load change
V
o
over/undershoot
V
in
=10V, I
o
=0.5×I
max,
V
o
= -5V
Over V
in
and I
o
ranges
Free Air Convection, (40-60LFM)
Over V
in
Range
Free Air Convection, (40-60LFM)
—
Per Mil-STD-883D, Method 2002.3
Per Mil-STD-883D, Method 2007.2,
20-2000 Hz, soldered in a PC board
—
θ
ja
T
s
—
—
—
Notes:
(1)
The PT78NR100 Series requires a 100µF electrolytic or tantalum capacitor at both the input and output for proper operation in all applications. The input
capacitor, C
1
must have a ripple current rating
≥
600 mArms, and an ESR
≤
0.2
Ω
.
(2) The ISR will operate down to no load with reduced specifications.
(3) See Thermal Derating chart.
For technical support and more information, see inside back cover or visit www.ti.com/powertrends
PT78NR100 Series
1 Amp Plus to Minus Voltage
Integrated Switching Regulator
Typical Characteristics
PT78NR105 -5.0 VDC
(See Note A)
PT78NR109 -9.0 VDC
(See Note A)
PT78NR112 -12.0 VDC
(See Note A)
Efficiency vs Output Current
100
100
Efficiency vs Output Current
100
Efficiency vs Output Current
90
90
90
Efficiency - %
Efficiency - %
Efficiency - %
80
Vin
7.0V
12.0V
15.0V
20.0V
25.0V
80
V
IN
80
7.0V
9.0V
12.0V
15.0V
18.0V
Vin
7.0V
70
70
12.0V
15.0V
18.0V
21.0V
70
60
60
60
50
50
50
40
0
0.2
0.4
0.6
0.8
1
40
0
0.1
0.2
0.3
0.4
0.5
40
0
0.1
0.2
0.3
0.4
Iout-(Amps)
Iout-(Amps)
Iout-(Amps)
Ripple vs Output Current
200
200
Ripple vs Output Current
250
Ripple vs Output Current
160
Vin
160
Vin
200
V
IN
120
80
25.0V
20.0V
15.0V
12.0V
7.0V
Ripple - mV
Ripple-(mV)
Ripple-(mV)
120
21.0V
18.0V
15.0V
12.0V
7.0V
150
80
100
18.0V
15.0V
12.0V
9.0V
7.0V
40
40
50
0
0
0.2
0.4
0.6
0.8
1
0
0
0.1
0.2
0.3
0.4
0.5
0
0
0.1
0.2
0.3
0.4
Iout-(Amps)
Iout-(Amps)
Iout-(Amps)
Thermal Derating (T
a
)
1
0.9
0.8
(See Note B)
60°C
70°C
0.5
0.6
Thermal Derating (T
a
)
(See Note B)
0.4
Thermal Derating (T
a
)
(See Note B)
70°C
70°C
0.35
0.3
Iout-(Amps)
Iout-(Amps)
85°C
0.6
0.5
0.4
0.3
0.2
0.4
Iout-(Amps)
0.7
0.25
0.2
0.15
0.1
85°C
0.3
85°C
0.2
0.1
0.1
0
7
10
13
16
19
22
25
0
7
11
15
19
0.05
0
7
10
13
16
19
Vin-(Volts)
Vin-(Volts)
Vin-(Volts)
Power Dissipation vs Output Current
2
1.8
1.6
Power Dissipation vs Output Current
1.6
Power Dissipation vs Output Current
1.6
1.4
1.4
1.2
1.4
Vin
25.0V
1.2
1
0.8
0.6
20.0V
15.0V
12.0V
7.0V
Vin
1.2
PD-(Watts)
V
IN
18.0V
15.0V
12.0V
9.0V
7.0V
21.0V
18.0V
15.0V
12.0V
7.0V
Pd - Watts
PD-(Watts)
1
0.8
0.6
0.4
1
0.8
0.6
0.4
0.4
0.2
0.2
0
0
0.2
0.4
0.6
0.8
1
0.2
0
0
0.1
0.2
0.3
0.4
0.5
0
0
0.1
0.2
0.3
0.4
Iout-(Amps)
Iout-(Amps)
Iout-(Amps)
Note A:
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 B:
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
IMPORTANT NOTICE
Texas Instruments and its subsidiaries (TI) reserve the right to make changes to their products or to discontinue
any product or service without notice, and advise customers to obtain the latest version of relevant information
to verify, before placing orders, that information being relied on is current and complete. All products are sold
subject to the terms and conditions of sale supplied at the time of order acknowledgment, including those
pertaining to warranty, patent infringement, and limitation of liability.
TI warrants performance of its semiconductor products to the specifications applicable at the time of sale in
accordance with TI’s standard warranty. Testing and other quality control techniques are utilized to the extent
TI deems necessary to support this warranty. Specific testing of all parameters of each device is not necessarily
performed, except those mandated by government requirements.
Customers are responsible for their applications using TI components.
In order to minimize risks associated with the customer’s applications, adequate design and operating
safeguards must be provided by the customer to minimize inherent or procedural hazards.
TI assumes no liability for applications assistance or customer product design. TI does not warrant or represent
that any license, either express or implied, is granted under any patent right, copyright, mask work right, or other
intellectual property right of TI covering or relating to any combination, machine, or process in which such
semiconductor products or services might be or are used. TI’s publication of information regarding any third
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