LT1970 Datasheet, PDF (1/12 Pages) Linear Technology – 500mA Power Op Amp with Adjustable Precision Current Limit

LT1970
500mA Power Op Amp with
Adjustable Precision Current Limit
FEATURES
s _{±500mA Minimum Output Current}
s _{Independent Adjustment of Source and}
Sink Current Limits
s _{2% Current Limit Accuracy}
s _{Operates with Single or Split Supplies}
s _{Shutdown/Enable Control Input}
s _{Open Collector Status Flags:}
Sink Current Limit
Source Current Limit
Thermal Shutdown
s _{Fail Safe Current Limit and Thermal Shutdown}
s _{1.6V/µs Slew Rate}
s _{3.6MHz Gain Bandwidth Product}
s _{Fast Current Limit Response: 2MHz Bandwidth}
s _{Specified Temperature Range: – 40°C to 85°C}
U
APPLICATIO S
s _{Automatic Test Equipment}
s _{Laboratory Power Supplies}
s _{Motor Drivers}
s _{Thermoelectric Cooler Driver}
, LTC and LT are registered trademarks of Linear Technology Corporation.
DESCRIPTIO
The LT^®1970 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 2% 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 operation, the
input stage supplies and the output stage supplies are con-
nected (V_CC to V⁺ and V_EE to V^–). To reduce power dissi-
pation 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 current limit circuits operate with a 2MHz re-
sponse between the VC_SRC or VC_SNK control inputs and
the amplifier output.
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 shut-
down and a ±800mA fixed current limit protect the chip
under fault conditions.
The LT1970 is packaged in a 20-lead TSSOP package with
a thermally conductive copper bottom plate to facilitate
heat sinking.
TYPICAL APPLICATIO
A_V = 2 Amplifier with Adjustable ±500mA Full-Scale
Current Limit and Fault indication
V_LIMIT
0V TO 5V
15V
15V
I_OUT(LIMIT)
=
±
V_LIMIT
10 • R_CS
V_{CC V+}
3k
VC_SRC
V_IN
+IN
VC_SNK
ISNK
ISRC
R_CS
I_OUT ^1Ω
TSD
1/4W
LT1970
OUT
SENSE⁺
SENSE^–
–IN
V_EE ^V–
COMMON
–15V
R1 ^LOAD
10k
R2
10k
1970 TA01
Current Limited Sinewave Into 10Ω Load
4V
2V
V_LOAD
0V
– 2V
VC_SRC = 4V
VC_SNK = 2V
R_CS = 1Ω
20µs/DIV
1970 TA02
1970f
1