externally controlled current limiting. Separate control
voltages program the sourcing and sinking current limit
sense thresholds with 1% accuracy. Output current may
be boosted by adding external power transistors.
The circuit operates with single or split power supplies
from 5V to 36V total supply voltage. In normal opera-
tion, the input stage supplies and the output stage sup-
plies are connected (V
CC
to V
+
and V
EE
to V
–
). To reduce
power dissipation it is possible to power the output stage
(V
+
, V
–
) from independent, lower voltage rails. The amplifier
is unity-gain stable with a 3.6MHz gain-bandwidth product
and slews at 1.6V/µs. The LT1970A can drive capacitive
and inductive loads directly.
Open-collector status flags signal current limit circuit
activation, as well as thermal shutdown of the amplifier.
An enable logic input puts the amplifier into a low power,
high impedance output state when pulled low. Thermal
shutdown and a ±800mA fixed current limit protect the
chip under fault conditions.
The LT1970A is packaged in a 20-lead TSSOP package with
a thermally conductive copper bottom plate to facilitate
heat sinking.
n
n
n
n
n
n
n
n
n
n
± 500mA Minimum Output Current
Independent Adjustment of Source and
Sink Current Limits
1% Current Limit Accuracy
Improved Reactive Load Driving Stability
Operates with Single or Split Supplies
Shutdown/Enable Control Input
Open-Collector Status Flags:
Sink Current Limit
Source Current Limit
Thermal Shutdown
Fail-Safe Current Limit and Thermal Shutdown
1.6V/µs Slew Rate
3.6MHz Gain-Bandwidth Product
Specified Temperature Range: –40°C to 85°C
Available in a 20-Lead TSSOP Package
APPLICATIONS
n
n
n
n
Automatic Test Equipment
Laboratory Power Supplies
Motor Drivers
Thermoelectric Cooler Driver
L,
LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear
Technology Corporation. All other trademarks are the property of their respective owners.
TYPICAL APPLICATION
Device Power Supply (DPS) with ±500mA Adjustable Current Limit
V
LIMIT
0V TO 5V
20V
20V
6k
CURRENT LIMIT = 500mA
V
I
OUT(MAX)
= ±
LIMIT
10 • R
CS
I
OUT
R
CS
1
1/4W
TRACE R TRACE L
100m
200nH
4.7µF
SENSE
ESR
0.1
1970A TA01
V
CC
V
IN
V
+
EN
VC
SRC
+IN
VC
SNK
ISNK
V
LOAD
, R
LOAD
= 100
ISRC
TSD
LT1970A
OUT
SENSE
+
SENSE
–
V
–
–IN
V
EE
COMMON
2V/DIV
V
LOAD
,
R
LOAD
= 10
V
IN
, 5V/DIV
LOAD
0V
–5V
10k
100pF
100µs/DIV
1970A TA01b
1970afb
For more information
www.linear.com/LT1970A
1
LT1970A
ABSOLUTE MAXIMUM RATINGS
(Note 1)
PIN CONFIGURATION
TOP VIEW
V
EE
V
–
OUT
SENSE
+
FILTER
SENSE
–
V
CC
–IN
+IN
1
2
3
4
5
6
7
8
9
21
20 V
EE
19 V
+
18
TSD
17
ISNK
16
ISRC
V
EE
10
FE PACKAGE
20-LEAD PLASTIC TSSOP
T
JMAX
= 150°C,
θ
JA
= 40°C/W (NOTE 8)
EXPOSED PAD (PIN 21) IS CONNECTED TO V
EE
ORDER INFORMATION
LEAD FREE FINISH
LT1970ACFE#PBF
LT1970AIFE#PBF
TAPE AND REEL
LT1970ACFE#TRPBF
LT1970AIFE#TRPBF
PART MARKING*
LT1970AFE
LT1970AFE
PACKAGE DESCRIPTION
20-Lead Plastic TSSOP
20-Lead Plastic TSSOP
SPECIFIED TEMPERATURE RANGE
0°C to 70°C
–40°C to 85°C
Consult LTC Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container.
Consult LTC Marketing for information on non-standard lead based finish parts.
For more information on lead free part marking, go to:
http://www.linear.com/leadfree/
For more information on tape and reel specifications, go to:
http://www.linear.com/tapeandreel/
The
l
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. See Test Circuit for standard test conditions.
SYMBOL
V
OS
PARAMETER
Input Offset Voltage
Input Offset Voltage Drift (Note 4)
I
OS
I
B
Input Offset Current
Input Bias Current
Input Noise Voltage
V
CM
= 0V
V
CM
= 0V
0.1Hz to 10Hz
CONDITIONS
MIN
TYP
200
l
l
l
l
l
ELECTRICAL CHARACTERISTICS
Power Op Amp Characteristics
0°C < T
A
< 70°C
–40°C < T
A
< 85°C
600
1000
1300
10
100
–160
3
µV
µV
µV
µV/°C
nA
nA
µV
P-P
1970afb
2
For more information
www.linear.com/LT1970A
+ –
–10
–100
–600
Supply Voltage (V
CC
to V
EE
) ..................................... 36V
Positive High Current Supply (V
+
)................... V
–
to V
CC
Negative High Current Supply(V
–
) ....................V
EE
to V
+
Amplifier Output (OUT) ..................................... V
Microchip MCU
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