LT1970A Datasheet, PDF (1/24 Pages) Linear Technology – 500mA Power Op Amp with Adjustable Precision Current Limit

LT1970A
500mA Power Op Amp with
Adjustable Precision Current Limit
FEATURES
DESCRIPTION
n _{± 500mA Minimum Output Current}
n _{Independent Adjustment of Source and}
Sink Current Limits
n _{1% Current Limit Accuracy}
n _{Improved Reactive Load Driving Stability}
n _{Operates with Single or Split Supplies}
n _{Shutdown/Enable Control Input}
n _{Open-Collector Status Flags:}
Sink Current Limit
Source Current Limit
Thermal Shutdown
n _{Fail-Safe Current Limit and Thermal Shutdown}
n _{1.6V/μs Slew Rate}
n _{3.6MHz Gain-Bandwidth Product}
n _{Specified Temperature Range: –40°C to 85°C}
n _{Available in a 20-Lead TSSOP Package}
APPLICATIONS
n _{Automatic Test Equipment}
n _{Laboratory Power Supplies}
n _{Motor Drivers}
n _{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.
The LT^®1970A is a ± 500mA power op amp with precise
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.
TYPICAL APPLICATION
Device Power Supply (DPS) with ±500mA Adjustable Current Limit
V_LIMIT
0V TO 5V
V_IN
20V
20V
6k
V_{CC V+}
EN
+IN
VC_SRC
VC_SNK
ISNK
ISRC
TSD
LT1970A
OUT
SENSE⁺
SENSE^–
V^–
–IN
V_EE
COMMON
I_OUT(MAX)
=
±
V_LIMIT

t
3_CS
I_OUT
R_CS
1Ω
1/4W
TRACE R TRACE L
100mΩ 200nH
SENSE
4.7μF
ESR
0.1Ω
LOAD
1970A TA01
–5V
10k
100pF
CURRENT LIMIT = 500mA
V_LOAD, R_LOAD = 100Ω
2V/DIV
0V
V_LOAD,
R_LOAD = 10Ω
V_IN, 5V/DIV
100μs/DIV
1970A TA01b
1970afa
1