LT1970 Datasheet PDF - Linear Technology

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LT1970
Linear Technology

Part Number LT1970
Description 500mA Power Op Amp with Adjustable Precision Current Limit
Page 12 Pages


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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 (VCC to V+ and VEE 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 VCSRC or VCSNK 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
AV = 2 Amplifier with Adjustable ±500mA Full-Scale
Current Limit and Fault indication
VLIMIT
0V TO 5V
15V
15V
IOUT(LIMIT)
=
±
VLIMIT
10 • RCS
VCC V+
3k
VCSRC
VIN
+IN VCSNK
ISNK
ISRC
RCS
IOUT 1
TSD 1/4W
LT1970
OUT
SENSE+
SENSE
–IN VEE V
COMMON
–15V
R1 LOAD
10k
R2
10k
1970 TA01
Current Limited Sinewave Into 10Load
4V
2V
VLOAD
0V
– 2V
VCSRC = 4V
VCSNK = 2V
RCS = 1
20µs/DIV
1970 TA02
1970f
1



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LT1970
ABSOLUTE AXI U RATI GS
(Note 1)
Supply Voltage (VCC to VEE).................................... 36V
Positive High Current Supply (V+) .................. Vto VCC
Negative High Current Supply(V) ................... VEE to V+
Amplifier Output (OUT) ..................................... Vto V+
Current Sense Pins
(SENSE+, SENSE, FILTER) .......................... Vto V+
Logic Outputs (ISRC, ISNK, TSD) ....... COMMON to VCC
Input Voltage (–IN, +IN) .......... VEE – 0.3V to VEE + 36V
Input Current ....................................................... 10mA
Current Control Inputs
(VCSRC, VCSNK) ............. COMMON to COMMON + 7V
Enable Logic Input .............................. COMMON to VCC
COMMON ..................................................... VEE to VCC
Output Short-Circuit Duration ......................... Indefinite
Operating Temperature Range (Note 2) .. – 40°C to 85°C
Specified Temperature Range (Note 3) ... – 40°C to 85°C
Maximum Junction Temperature ......................... 150°C
Storage Temperature Range ................. – 65°C to 150°C
Lead Temperature (Soldering, 10 sec).................. 300°C
UW U
PACKAGE/ORDER I FOR ATIO
TOP VIEW
VEE 1
V2
OUT 3
SENSE+ 4
FILTER 5
SENSE6
VCC 7
–IN 8
+IN 9
VEE 10
–+
20 VEE
19 V+
18 TSD
17 ISNK
16 ISRC
15 ENABLE
14 COMMON
13 VCSRC
12 VCSNK
11 VEE
ORDER PART
NUMBER
LT1970CFE
FE PACKAGE
20-LEAD PLASTIC TSSOP
TJMAX = 150°C, θJA = 40°C/ W (NOTE 6)
UNDERSIDE METAL CONNECTED TO VEE
Consult LTC Marketing for parts specified with wider operating temperature ranges.
ELECTRICAL CHARACTERISTICS The q denotes specifications which apply over the full operating
temperature range, otherwise specifications are TA = 25°C. See Test Circuit for standard test conditions.
SYMBOL PARAMETER
CONDITIONS
MIN TYP MAX
Power Op Amp Characteristics
VOS Input Offset Voltage
0°C < TA < 70°C
–40°C < TA < 85°C
Input Offset Voltage Drift (Note 4)
200 600
q 800
q 1000
q –10
–4
10
IOS Input Offset Current
IB Input Bias Current
Input Noise Voltage
VCM = 0V
VCM = 0V
0.1Hz to 10Hz
q –100
q –600
–160
3
100
en Input Noise Voltage Density
in Input Noise Current Density
RIN Input Resistance
1kHz
1kHz
Common Mode
Differential Mode
15
3
500
100
CIN Input Capacitance
VCM Input Voltage Range
Pin 8 and Pin 9 to Ground
Typical
Guaranteed by CMRR Test
–14.5
q –12.0
6
13.6
12.0
CMRR
PSRR
Common Mode Rejection Ratio
Power Supply Rejection Ratio
–12V < VCM < 12V
q 92
VEE = V= –5V, VCC = V+ = 3V to 30V
q 90
VEE = V= –5V, VCC = 30V, V+ = 2.5V to 30V
q 110
VEE = V= –3V to – 30V, VCC = V+ = 5V
q 90
VEE = –30V, V= –2.5V to –30V, VCC = V+ = 5V q 110
105
100
130
100
130
2
UNITS
µV
µV
µV
µV/°C
nA
nA
µVP-P
nV/Hz
pA/Hz
k
k
pF
V
V
dB
dB
dB
dB
dB
1970f



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LT1970
ELECTRICAL CHARACTERISTICS The q denotes specifications which apply over the full operating
temperature range, otherwise specifications are TA = 25°C. See Test Circuit for standard test conditions.
SYMBOL
PARAMETER
CONDITIONS
MIN
AVOL Large-Signal Voltage Gain
RL = 1k, –12.5V < VOUT < 12.5V
100
q 75
VOL
VOH
ISC
SR
FPBW
GBW
Output Sat Voltage Low
Output Sat Voltage High
Output Short-Circuit Current
Slew Rate
Full Power Bandwidth
Gain Bandwidth Product
RL = 100, –12.5V < VOUT < 12.5V
RL = 10, –5V < VOUT < 5V, V+ = – V= 8V
VOL = VOUT – V
RL = 100, VCC = V+ = 15V, VEE = V= –15V
RL = 10, VCC = – VEE = 15V, V+ = –V= 5V
VOH = V+ – VOUT
RL = 100, VCC = V+ = 15V, VEE = V= –15V
RL = 10, VCC = – VEE = 15V, V+ = –V= 5V
Output Low, RSENSE = 0
Output High, RSENSE = 0
–10V < VOUT < 10V, RL = 1k
VOUT = 10VPEAK (Note 5)
f = 10kHz
80
q 40
20
q5
q
q
500
– 1000
0.7
11
tS Settling Time
Current Sense Characteristics
0.01%, VOUT = 0V to 10V, AV = –1, RL = 1k
VSENSE(MIN) Minimum Current Sense Voltage
VCSRC = VCSNK = 0V
0.1
q 0.1
VSENSE(4%)
VSENSE(10%)
VSENSE(FS)
Current Sense Voltage 4% of Full Scale
Current Sense Voltage 10% of Full Scale
Current Sense Voltage 100% of Full Scale
VCSRC = VCSNK = 0.2V
VCSRC = VCSNK = 0.5V
VCSRC = VCSNK = 5V
q 15
q 45
490
q 480
IBI
ISENSE
Current Limit Control Input Bias Current
SENSEInput Current
VCSRC, VCSNK Pins
0V < (VCSRC, VCSNK) < 5V
IFILTER
ISENSE+
FILTER Input Current
SENSE+ Input Current
0V < (VCSRC, VCSNK) < 5V
VCSRC= VCSNK = 0V
VCSRC = 5V, VCSNK = 0V
VCSRC= 0V, VCSNK = 5V
VCSRC = VCSNK = 5V
Current Sense Change with Output Voltage VCSRC = VCSNK = 5V, –12.5V < VOUT < 12.5V
Current Sense Change with Supply Voltage VCSRC = VCSNK = 5V, 6V < (VCC, V+) < 18V
2.5V < V+ < 18V, VCC = 18V
–18V < (VEE, V) < –2.5V
–18V < V< –2.5V, VEE = –18V
Current Sense Bandwidth
RCSF Resistance FILTER to SENSE
Logic I/O Characteristics
q
q
q
q
q
q
q
q
q
–1
– 200
– 200
– 500
200
– 300
– 25
– 0.1
750
Logic Output Leakage ISRC, ISNK, TSD V = 15V
q
Logic Low Output Level
I = 5mA
q
Logic Output Current Limit
q
VENABLE
IENABLE
Enable Logic Threshold
Enable Pin Bias Current
q 0.8
q –1
TYP
150
120
60
1.9
0.8
1.7
1.0
800
– 800
1.6
3.6
8
4
20
50
500
500
– 0.2
250
– 250
±0.05
±0.01
±0.05
±0.01
2
1000
0.2
25
1.6
MAX
2.4
2.2
1200
– 500
7
10
25
55
510
520
0.1
200
200
500
300
– 200
25
0.1
1250
1
0.4
2.4
1
UNITS
V/mV
V/mV
V/mV
V/mV
V/mV
V/mV
V
V
V
V
mA
mA
V/µs
kHz
MHz
µs
mV
mV
mV
mV
mV
mV
µA
nA
nA
nA
µA
µA
µA
%
%
%
%
%
MHz
µA
V
mA
V
µA
1970f
3



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LT1970
ELECTRICAL CHARACTERISTICS The q denotes specifications which apply over the full operating
temperature range, otherwise specifications are TA = 25°C. See Test Circuit for standard test conditions.
SYMBOL
ISUPPLY
ICC
ICC(STBY)
tON
tOFF
PARAMETER
Total Supply Current
VCC Supply Current
Supply Current Disabled
Turn-On Delay
Turn-Off Delay
CONDITIONS
MIN TYP MAX
VCC, V+ and V, VEE Connected
VCC, V+ and V, VEE Separate
VCC, V+ and V, VEE Connected, VENABLE 0.8V
(Note 7)
q
q
q
7 13
37
0.6 1.5
10
(Note 7)
10
UNITS
mA
mA
mA
µs
µs
Note 1: Absolute Maximum Ratings are those values beyond which the life
of a device may be impaired.
Note 2: The LT1970C is guaranteed functional over the operating
temperature range of – 40°C and 85°C.
Note 3: The LT1970C is guaranteed to meet specified performance from
0°C to 70°C. The LT1970C is designed, characterized and expected to
meet specified performance from – 40°C to 85°C but is not tested or QA
sampled at these temperatures.
Note 4: This parameter is not 100% tested.
Note 5: Full power bandwidth is calculated from slew rate measurements:
FPBW = SR/(2 • π • VP)
Note 6: Thermal resistance varies depending upon the amount of PC board
metal attached to the device. If the maximum dissipation of the package is
exceeded, the device will go into thermal shutdown and be protected.
Note 7: Turn-on and turn-off delay are measured from VENABLE crossing
1.6V to the OUT pin at 90% of normal output voltage.
TYPICAL PERFOR A CE CHARACTERISTICS
Warm-Up Drift VIO vs Time
TIME (100ms/DIV)
0V
1970 G04
Input Bias Current vs VCM
–100
VS = ±15V
–120
–140
–160
–180
–IBIAS
+IBIAS
–200
– 220
–240
–260
–15 –12 –9 –6 –3 0 3 6 9 12 15
COMMON MODE INPUT VOLTAGE (V)
1970 G05
Total Supply Current
vs Supply Voltage
14
12
10
ICC + IV+
125°C
8 25°C
6
4
2 –55°C
0
–2
IEE + IV
–4
–55°C
–6
–8
25°C
–10 125°C
–12
–14
0 2 4 6 8 10 12 14 16 18
SUPPLY VOLTAGE (±V)
1970 G15
1970f
4



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