FEATURES
s s s s s s s s s s s s s s
LT1784 2.5MHz, Over-The-Top Low Power, Rail-to-Rail Input and Output Op Amp in SOT-23 DESCRIPTIO
The LT®1784 is a 2.5MHz op amp available in the small SOT-23 package that operates on all single and split supplies with a total voltage of 2.5V to 18V. The amplifier draws less than 750µA of quiescent current and has reverse battery protection, drawing negligible current for reverse supply voltages up to 18V. The input range of the LT1784 includes ground, and a unique feature of this device is its Over-The-TopTM operation capabilitity with either or both of its inputs above the positive rail. The inputs handle 18V both differential and common mode, independent of supply voltage. The input stage incorporates phase reversal protection to prevent false outputs from occurring even when the inputs are 9V below the negative supply. The LT1784 can drive loads up to 15mA and still maintain rail-to-rail capability. A shutdown feature on the 6-lead version can disable the part, making the output high impedance and reducing quiescent current to 5µA. The LT1784 op amp is available in the 5- and 6-lead SOT-23 packages. For applications requiring lower power, refer to the LT1782 and LT1783 data sheets.
, LTC and LT are registered trademarks of Linear Technology Corporation. Over-The-Top and ThinSOT are trademarks of Linear Technology Corporation.
Operates with Inputs Above V + Rail-to-Rail Input and Output Low Profile (1mm) ThinSOTTM Package Gain Bandwidth Product: 2.5MHz Slew Rate: 2.1V/µs Low Input Offset Voltage: 3.5mV Max High Voltage Gain: 1000V/mV Single Supply Input Range: 0V to 18V Specified on 3V, 5V and ± 5V Supplies Reverse Battery Protection to 18V Low Power: 750µA Supply Current Max Output Shutdown on 6-Lead Version High Output Current: 15mA Min Operating Temperature Range: – 40°C to 85°C
APPLICATIO S
s s s s s s
Portable Instrumentation Battery-Powered Systems Sensor Conditioning Supply Current Sensing MUX Amplifiers 4mA to 20mA Transmitters
TYPICAL APPLICATIO
VCC AV = 20 AV = 2 SHDN IN SHDN VCC
Programmable Gain, AV = 2, AV = 20, 100kHz Amplifier
Programmable Gain Amplifier Frequency Response
30 25 AV = 20
VCC
20 15
+
LT1784 OUT
GAIN (dB)
10 5 0 –5 AV = 2
–
VEE
+
LT1782
–
VEE R2 9.09k R3 1k R1 10k AV = 1+
OR
1+
( (
R1 + R2 R3 R1 R2 + R3
) )
1784 TA01
–10 –15 –20 1k 10k 100k 1M FREQUENCY (Hz) 10M
1784 TA01a
U
U
U
1
LT1784
ABSOLUTE MAXIMUM RATINGS
Total Supply Voltage (V + to V –) .............................. 18V Input Differential Voltage ........................................ 18V Input Pin Voltage to V – ............................... + 24V/– 10V Shutdown Pin Voltage Above V – ............................ 18V Shutdown Pin Current ....................................... ±10mA Output Short-Circuit Duration (Note 2) ........... Indefinite
PACKAGE/ORDER INFORMATION
TOP VIEW OUT 1 V– 2 +IN 3
+–
ORDER PART NUMBER
5 V+ OUT 1 4 –IN
LT1784CS5 LT1784IS5 S5 PART MARKING LTJD LTSN
S5 PACKAGE 5-LEAD PLASTIC SOT-23
TJMAX = 150°C, θJA = 250°C/ W
Consult LTC marketing for parts specified with wider operating temperature ranges.
The q denotes specifications which apply over the specified temperature range, otherwise specifications are TA = 25°C. VS = 3V, 0V; VS = 5V, 0V, VCM = VOUT = half supply, for the 6-lead part VPIN5 = 0V, pulse power tested unless otherwise specified.
SYMBOL PARAMETER VOS Input Offset Voltage CONDITIONS TA = 25°C 0°C ≤ TA ≤ 70°C – 40°C ≤ TA ≤ 85°C – 40°C ≤ TA ≤ 85°C VCM = 18V (Note 3) IB Input Bias Current VCM = 18V (Note 3) SHDN or VS = 0V, VCM = 0V to 18V ∆IB/∆T en in RIN Input Bias Current Drift Input Noise Voltage Input Noise Voltage Density Input Noise Current Density Input Resistance – 40°C ≤ TA ≤ 85°C 0.1Hz to 10Hz f = 10kHz f = 10kHz Differential Common Mode, VCM = 0V to (VCC – 1.2V) Common Mode, VCM = 0V to 18V
q q q q q q q q q
ELECTRICAL CHARACTERISTICS
∆VOS/∆T Input Offset Voltage Drift (Note 7) IOS Input Offset Current
CIN VCM
Input Capacitance Input Voltage Range 0
2
U
U
W
WW
U
W
(Note 1)
Operating Temperature Range (Note 10) – 40°C to 85°C Specified Temperature Range (Note 11) – 40°C to 85°C Junction Temperature........................................... 150°C Storage Temperature Range ................ – 65°C to 150°C Lead Temperature (Soldering, 10 sec)................. 300°C
TOP VIEW
+ 6V
+–
ORDER PART NUMBER
5 SHDN 4 –IN
V– 2 +IN 3
LT1784CS6 LT1784IS6 S6 PART MARKING LTIW LTIX
S6 PACKAGE 6-LEAD PLASTIC SOT-23
TJMAX = 150°C, θJA = 230°C/ W
MIN
TYP 1.5
MAX 3.5 4.2 4.5 15 50 50 500 400
UNITS mV mV mV µV/°C nA µA nA µA nA nA/°C µVP-P nV/√Hz pA/√Hz kΩ MΩ kΩ pF
5 25 250 225 0.1 0.4 1.5 25 0.3 100 45 200 150 80 5
18
V
LT1784
ELECTRICAL CHARACTERISTICS
SYMBOL PARAMETER CMRR PSRR AVOL Common Mode Rejection Ratio (Note 3) Power Supply Rejection Ratio Large-Signal Voltage Gain CONDITIONS
The q denotes specifications which apply over the specified temperature range, otherwise specifications are TA = 25°C. VS = 3V, 0V; VS = 5V, 0V, VCM = VOUT = half supply, for the 6-lead part VPIN5 = 0V, pulse power tested unless otherwise specified.
MIN
q q q q q q q q q q q q q q
TYP 95 70 100 1000
MAX
UNITS dB dB dB V/mV V/mV V/mV V/mV V/mV V/mV
VCM = 0V to VCC – 1.2V VCM = 0V to 18V (Note 6) VS = 3V to 12.5V, VCM = VO = 1V VS = 3V, VO = 500mV to 2.5V, RL = 10k VS = 3V, 0°C ≤ TA ≤ 70°C VS = 3V, – 40°C ≤ TA ≤ 85°C VS = 5V, VO = 500mV to 4.5V, RL = 10k VS = 5V, 0°C ≤ TA ≤ 70°C VS = 5V, – 40°C ≤ TA ≤ 85°C
84 60 90 133 90 60 266 180 120
1000
VOL
Output Voltage Swing LOW
No Load ISINK = 5mA VS = 5V, ISINK = 10mA VS = 3V, No Load VS = 3V, ISOURCE = 3mA VS = 5V, No Load VS = 5V, ISOURCE = 10mA
4 200 350 2.885 2.600 4.885 4.400 4 15 12.5 20.0 2.93 2.8 4.93 4.7 7.5 30 22 40 2.5 18 500
10 400 600
mV mV mV V V V V mA mA mA mA
VOH
Output Voltage Swing HIGH
ISC
Short-Circuit Current (Note 2)
VS = 3V, Short to GND VS = 3V, Short to VCC VS = 5V, Short to GND VS = 5V, Short to VCC
Minimum Supply Voltage Reverse Supply Voltage IS Supply Current (Note 4) Supply Current, Shutdown ISHDN SHDN Pin Current VPIN5 = 2V, No Load (Note 8) VPIN5 = 0.3V (On), No load (Note 8) VPIN5 = 2V (Shutdown), No Load (Note 8) VPIN5 = 5V (Shutdown), No Load (Note 8) VPIN5 = 2V, No Load (Note 8) VPIN5 = 18V, No Load (Note 8) (Note 8) (Note 8) VPIN5 = 5V to 0V, RL = 10k (Note 8) VPIN5 = 0V to 5V, RL = 10k (Note 8) f = 5kHz 0°C ≤ TA ≤ 70°C – 40°C ≤ TA ≤ 85°C AV = –1, RL = ∞ 0°C ≤ TA ≤ 70°C – 40°C ≤ TA ≤ 85°C VOUT = 2VP-P VS = 5V, ∆VOUT = 2V to 0.1%, AV = – 1 VS = 3V, VO = 1.8VP-P, AV = 1, RL = 10k, f = 1kHz IS = –100µA
q q q q q q q q q q
2.7 750 900 18 8 1 30 0.3
V V µA µA µA nA µA µA µA µA V V µs µs MHz MHz MHz V/µs V/µs V/µs kHz µs %
7 0.5 2.0 5.0 0.05 10 2 18 2.2 1.5 1.2 1.1 1.2 1.1 1.0 2.5
Output Leakage Current, Shutdown Maximum SHDN Pin Current VIL VIH tON tOFF GBW SHDN Pin Input Low Voltage SHDN Pin Input High Voltage Turn-On Time Turn-Off Time Gain Bandwidth Product (Note 4) Slew Rate (Note 5) Full-Power Bandwidth (Note 9) Settling Time Distortion
q q q q
SR
2.1
FPBW tS THD
350 3.7 0.001
3
LT1784
ELECTRICAL CHARACTERISTICS
SYMBOL PARAMETER VOS Input Offset Voltage CONDITIONS
The q denotes specifications which apply over the specified temperature range, otherwise specifications are TA = 25°C. VS = ±5V, VCM = 0V,VOUT = 0V, for the 6-lead part VPIN5 = V –, pulse power tested unless otherwise specified.
MIN
q q q q q
TYP 1.6
MAX 3.75 4.50 4.80 15 50 500
UNITS mV mV mV µV/°C nA nA nA/°C µVP-P nV/√Hz pA/√Hz kΩ kΩ pF
TA = 25°C 0°C ≤ TA ≤ 70°C – 40°C ≤ TA ≤ 85°C –40°C ≤ TA ≤ 85°C
∆VOS/∆T Input Offset Voltage Drift (Note 7) IOS IB ∆IB/∆T en in RIN CIN VCM CMRR AVOL VOL Input Offset Current Input Bias Current Input Bias Current Drift Input Noise Voltage Input Noise Voltage Density Input Noise Current Density Input Resistance Input Capacitance Input Voltage Range Common Mode Rejection Ratio Large-Signal Voltage Gain Output Voltage Swing LOW
5 25 250 0.4 1.5 25 0.3
0°C ≤ TA ≤ 70°C 0.1Hz to 10Hz f = 1kHz f = 1kHz Differential Common Mode, VCM = –5V to 13V
q
q q
100 45 –5 60 50 35
200 80 5 13 70 100 – 4.996 – 4.800 – 4.650 – 4.99 – 4.60 – 4.40
q
V dB V/mV V/mV V V V V V V mA mA dB
VCM = –5V to 13V VO = ±4V, RL= 10k 0°C ≤ TA ≤ 70°C No Load ISINK = 5mA ISINK = 10mA No Load ISOURCE = 5mA ISOURCE = 10mA Short to GND 0°C ≤ TA ≤ 70°C VS = ±1.5V to ±9V
q q q q q q q q q q q
VOH
Output Voltage Swing HIGH
4.885 4.550 4.400 15 10 90
4.92 4.75 4.65 27 100 540 800 975 20 8 30 1 – 4.7
ISC PSRR IS
Short-Circuit Current (Note 2) Power Supply Rejection Ratio Supply Current Supply Current, Shutdown
µA µA µA nA µA µA µA V V µs µs MHz MHz MHz
VPIN5 = –3V, VS = ±5V, No Load (Note 8) VPIN5 = –4.7V (On), VS = ±5V, No load (Note 8) VPIN5 = –3V (Shutdown), VS = ±5V, No Load (Note 8) VPIN5 = 9V, VS = ±9V (Note 8) VPIN5 = –7V, VS = ±9V, No Load (Note 8) VS = ±5V (Note 8) VS = ±5V (Note 8) VPIN5 = 0V to –5V, RL = 10k (Note 8) VPIN5 = –5V to 0V, RL = 10k (Note 8) f = 5kHz 0°C ≤ TA ≤ 70°C –40°C ≤ TA ≤ 85°C
q q q q q q q q q q q
8 0.5 2.0 10 0.05 –3 18 2.2 1.55 1.30 1.20 2.6
ISHDN
SHDN Pin Current Maximum SHDN Pin Current Output Leakage Current, Shutdown
VIL VIH tON tOFF GBW
SHDN Pin Input Low Voltage SHDN Pin Input High Voltage Turn-On Time Turn-Off Time Gain Bandwidth Product
4
LT1784
ELECTRICAL CHARACTERISTICS
SYMBOL PARAMETER SR Slew Rate CONDITIONS
The q denotes specifications which apply over the specified temperature range, otherwise specifications are TA = 25°C. VS = ±5V, VCM = 0V,VOUT = 0V, for the 6-lead part VPIN5 = V –, pulse power tested unless otherwise specified.
MIN
q q
TYP 2.2
MAX
UNITS V/µs V/µs V/µs kHz µs
AV = –1, RL = ∞, VO = ±4V, Measured at VO = ±2V 0°C ≤ TA ≤ 70°C –40°C ≤ TA ≤ 85°C VOUT = 8VP-P VS = 5V, ∆VOUT = 4V to 0.1%, AV = 1
1.3 1.2 1.1
FPBW tS
Full-Power Bandwidth (Note 9) Settling Time
94 3.4
Note 1: Absolute Maximum Ratings are those values beyond which the life of a device may be impaired. Note 2: A heat sink may be required to keep the junction temperature below absolute maximum. Note 3: VS = 5V limits are guaranteed by correlation to VS = 3V and VS = ± 5V or VS = ± 9V tests. Note 4: VS = 3V limits are guaranteed by correlation to VS = 5V and VS = ± 5V or VS = ± 9V tests. Note 5: Guaranteed by correlation to slew rate at VS = ± 5V, and GBW at VS = 5V and VS = ± 5V tests.
Note 6: This specification implies a typical input offset voltage of 5.7mV at VCM = 18V and a maximum input offset voltage of 18mV at VCM = 18V. Note 7: This parameter is not 100% tested. Note 8: Specifications apply to 6-lead SOT-23 with shutdown. Note 9: Full-power bandwidth is calculated from the slew rate. FPBW = SR/2πVP. Note 10: The LT1784C is guaranteed functional over the operating temperature range – 40°C to 85°C. Note 11: The LT1784C is guaranteed to meet specified performance from 0°C to 70°C. The LT1784C 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. LT1784I is guaranteed to meet specified performance from – 40°C to 85°C.
TYPICAL PERFOR A CE CHARACTERISTICS
Supply Current vs Supply Voltage
700 650
SUPPLY CURRENT (µA) INPUT OFFSET VOLTAGE CHANGE (µV)
600 550 500 450 400 350 300 2
TA = 125°C TA = 25°C
0
TA = 125°C
TA = – 55°C
–100 –200 –300 –400 1
TA = 25°C
VOUT (V)
4
8 10 12 14 6 SUPPLY VOLTAGE (V)
UW
16
1784 G01
Minimum Supply Voltage
400 300 4 200 100 TA = – 55°C 3 5
Output Voltage vs Large Input Voltage
VS = 5V, 0V
2 VIN 1 + –
5V
18
3 2 4 TOTAL SUPPLY VOLTAGE (V)
5
1784 G02
0 –10
–6
–2
6 2 VIN (V)
10
14
18
1784 G03
5
LT1784 TYPICAL PERFOR A CE CHARACTERISTICS
Input Bias Current vs Common Mode Voltage
300,000 250,000 200,000 VS = 5V, 0V
OUTPUT SATURATION VOLTAGE (V)
150,000 100,000 TA = 25°C 800 600 400 200 0 –200 –400 3.5 4.5 5 5.5 14 16 18 4 COMMON MODE VOLTAGE (V)
1784 G04
OUTPUT SATURATION VOLTAGE (V)
INPUT BIAS CURRENT (nA)
TA = – 55°C TA = 125°C
Output Saturation Voltage vs Input Overdrive
100
OUTPUT SATURATION VOLTAGE (mV)
50
OUTPUT HIGH
45
OUTPUT CURRENT (mA)
40 SINKING 35
10 OUTPUT LOW
30
VS = ± 2.5V NO LOAD 1 0 10 20 30 40 50 INPUT OVERDRIVE (mV) 60
1784 G07
SOURCING 25 –50 –25 50 75 0 25 TEMPERATURE (°C) 100 125
NOISE VOLTAGE (400nV/DIV)
Noise Voltage Density vs Frequency
100 INPUT NOISE VOLTAGE DENSITY (nV/√Hz) 90 80 70 60 50 40 30 20 10 0 1 10 100 1k FREQUENCY (Hz) 10k 100k
1784 G10
INPUT NOISE CURRENT DENSITY (pA/√Hz)
VS = ± 2.5V
GAIN (dB)
6
UW
Output Saturation Voltage vs Load Current (Output High)
1 VS = ± 2.5V VOD = 30mV
1
Output Saturation Voltage vs Load Current (Output Low)
VS = ± 2.5V VOD = 30mV
0.1 TA = 25°C 0.01 TA = – 55°C 0.001 1
TA = 125°C
0.1
TA = 125°C TA = 25°C TA = – 55°C
0.01 1 100 10 1000 SOURCING LOAD CURRENT (µA) 10000
1784 G05
10 100 1000 SINKING LOAD CURRENT (µA)
10000
1784 G06
Output Short-Circuit Current vs Temperature
VS = ± 5V
0.1Hz to 10Hz Noise Voltage
VS = ± 2.5V
0
1
2
3
456 TIME (sec)
7
8
9
10
DC194 G02
1784 G09
Input Noise Current vs Frequency
1.6 1.4 1.2 1.0 0.8 0.6 0.4 0.2 0 1 10 100 1k FREQUENCY (Hz) 10k 100k
1784 G11
Gain and Phase Shift vs Frequency
70 60 50 40 30 20 10 0 –10 –20 –30 1k 10k 100k 1M FREQUENCY (Hz) GAIN VS = ± 2.5V PHASE 120 100 80 60
PHASE (DEG)
VS = ± 2.5V
40 20 0
–20 –40 –60 –80 10M
1784 G12
LT1784 TYPICAL PERFOR A CE CHARACTERISTICS
Gain Bandwidth Product vs Temperature
2.8
GAIN BANDWIDTH PRODUCT (MHz)
2.7
RISING
GAIN BANDWIDTH PRODUCT (MHz)
VS = ± 2.5V f = 5kHz
2.6 2.5 2.4 2.3 2.2 –50 –25
SLEW RATE (V/µs)
50 25 75 0 TEMPERATURE (°C)
Gain Bandwidth and Phase Margin vs Load Resistance
65
90
POWER SUPPLY REJECTION RATIO (dB)
COMMON MODE REJECTION RATIO (dB)
GAIN BANDWIDTHPRODUCT (MHz)
PHASE MARGIN
2.6 2.4 2.2 2.0 1k
GAIN BANDWIDTH PRODUCT
VS = ± 2.5V AV = –1 RF = RG = 10k f = 5kHz 10k LOAD RESISTANCE (Ω) 100k
1784 G16
Output Impedance vs Frequency
1k VS = ± 2.5V 1M
OUTPUT IMPEDANCE (Ω)
OUTPUT STEP (V)
AV = 100 10 AV = 10 1 AV = 1 0.1
OUTPUT IMPEDANCE (Ω)
100
0.01 100
1k
10k 100k FREQUENCY (Hz)
UW
100
1784 G13
1784 G19
Slew Rate vs Temperature
3.0 VS = ± 5V
Gain Bandwidth Product and Phase Margin vs Supply Voltage
AV = –1 RF = RG = 10k f = 5kHz 65 PHASE MARGIN 60
PHASE MARGIN (DEG)
2.5 FALLING
55 2.7 2.6 2.5 2.4 0 2 6 4 8 10 12 14 16 TOTAL SUPPLY VOLTAGE (V) 18 GAIN BANDWIDTH PRODUCT
2.0
125
1.5 –50 –25
50 25 75 0 TEMPERATURE (°C)
100
125
1784 G14
1784 G15
PSRR vs Frequency
60
PHASE MARGIN (DEG) 80 70 60 50 40 30 20 10 0 –10 1k 10k 100k FREQUENCY (Hz) 1M
1784 G17
CMRR vs Frequency
120 110 100 90 80 70 60 50 40 30 20 10k 100k FREQUENCY (Hz) 1M
1784 G18
VS = ± 2.5V
VS = ± 2.5V
55
POSITIVE SUPPLY
NEGATIVE SUPPLY
Disabled Output Impedance vs Frequency
VS = ± 2.5V VPIN 5 = 2.5V
Settling Time to 0.1% vs Output Step
5 4 3 2 1 0 –1 –2 –3 –4 AV = 1 AV = – 1 VS = ± 5V AV = 1 AV = – 1
100k
10k
1k
1M
100 100
–5
1k 10k 100k FREQUENCY (Hz) 1M
1784 G20
0
1
2
4 6 5 3 SETTLING TIME (µs)
7
8
1784 G21
7
LT1784 TYPICAL PERFOR A CE CHARACTERISTICS
Capacitive Load Handling Overshoot vs Capacitive Load
70 60 50 VS = 5V, 0V VCM = 2.5V
OUTPUT SWING (VP-P)
OVERSHOOT (%)
40 30 20 10 0 10 100 CAPACITIVE LOAD (pF)
AV = 5
6 4 2 0
VS = ± 2.5V
THD + NOISE (%)
Total Harmonic Distortion + Noise vs Load Resistance
1 VS = ± 1.5V VIN = ± 1V 0.1 AV = 1 VS = 3V TOTAL VIN = 2VP-P AT 1kHz THD + NOISE (%)
10
FREQUENCY = 1kHz VCM = HALF SUPPLY
INPUT OFFSET VOLTAGE CHANGE (50µV/DIV)
THD + NOISE (%)
0.01 VS = 3V, 0V VIN = 0.1V TO 2.1V
0.001
0.0001 100
1k
10k
LOAD RESISTANCE TO GROUND (Ω)
1784 G25
Supply Current vs SHDN Pin Voltage
600 550 500 TA = 125°C TA = 25°C TA = – 55°C VS = 5V, 0V
SUPPLY CURRENT (µA)
450 400 350 300 250 200 150 100 50 0 0
2 0.5 1.5 1 SHUTDOWN PIN VOLTAGE (V)
8
UW
AV = 1 AV = 10
1784 G28
Undistorted Output Swing vs Frequency
12 10 8 VS = ± 5V DISTORTION ≤ 1% AV = 1
Total Harmonic Distortion + Noise vs Frequency
0.1 RL = 10k VS = 3V, 0V VOUT = 1.8VP-P VCM = 1V
0.01
AV = –1 0.001 AV = 1
1000
1784 G22
1k
10k 100k FREQUENCY (Hz)
1M
1784 G23
0.0001 10
100
1k 10k FREQUENCY (Hz)
100k
1784 G24
Total Harmonic Distortion + Noise vs Output Voltage Amplitude
Open-Loop Gain
VS = ± 5V RL = 2k
1 AV = 1 VS = 3V, 0V 0.1 AV = –1 VS = 3V, 0V RF = RG = 10k
RL = 10k RL = 50k
AV = 1 VS = ±1.5V AV = –1 VS = ±1.5V RF = RG = 10k
0.01
0.001
100k
0
1 2 OUTPUT VOLTAGE AMPLITUDE (VP-P)
3
–6 –5 –4 –3 –2 –1 0 1 2 3 OUTPUT VOLTAGE (V)
4
5
6
1784 G26
1784 G27
Large Signal Response
Small Signal Response
2V/DIV
20mV/DIV
VS = ± 5V AV = 1 CL = 15pF
2.5
5µs/DIV
VS = ± 5V AV = 1 CL = 15pF
2µs/DIV
LT1784
APPLICATIO S I FOR ATIO
Supply Voltage
The positive supply pin of the LT1784 should be bypassed with a small capacitor (typically 0.1µF) within an inch of the pin. When driving heavy loads, and additional 4.7µF electrolytic capacitor should be used. When using split supplies the same is true for the negative supply pin. The LT1784 is protected against reverse battery voltages up to 18V. In the event a reverse battery condition occurs the supply current is less than 1nA. Inputs The LT1784 has two input stages, NPN and PNP (see the Simplified Schematic), resulting in three distinct operating regions as shown in the “Input Bias Current vs Common Mode” Typical Performance Characteristic Curve. For input voltages about 1V or more below V +, the PNP input stage is active and the input bias current is typically –250nA. When the input common mode voltage is within 0.6V of the positive rail, the NPN stage is operating and the input bias current is typically 500nA. Increases in temperature will cause the voltage at which operation switches from the PNP input stage to the NPN input stage to move towards V +. The input offset voltage of the NPN stage is untrimmed and is typically 3mV. A Schottky diode in the collector of the input transistors, along with special geometries for these NPN transistors, allow the LT1784 to operate with either or both of its inputs above V +. At about 0.3V above V +, the NPN input transistors is fully saturated and the input bias current is typically 200µA at room temperature. The input offset voltage is typically 3mV when operating above V +. The LT1784 will operate with inputs 18V above V – regardless of V+. The inputs are protected against excursions as much as 10V below V – by an internal 1k resistor in series with each input and a diode from the input to the negative supply. The input stage of the LT1784 incorporates phase reversal protection to prevent the output from phase reversing for inputs up to 9V below V –. There are no clamping diodes between the inputs and the maximum differential input voltage is 18V.
U
Output The output of the LT1784 can swing to within 80mV of the positive rail and within 4mV of the negative rail with no load. When monitoring input voltages within 80mV of the positive rail or within 4mV of the negative rail, gain should be taken to keep the output from clipping. The LT1784 can typically sink and source over 25mA at ±5V supplies, sourcing current is reduced to 7.5mA at 3V total supplies as noted in the electrical characteristics. The LT1784 is internally compensated to drive at least 400pF of capacitance under any output loading conditions. A 0.22µF capacitor in series with a 150Ω resistor between the output and ground will compensate these amplifiers for larger capacitive loads, up to 10,000pF at all output currents. Distortion There are two main contributors to distortion in op amps: output crossover distortion as the output transitions from sourcing to sinking current, and distortion caused by nonlinear common mode rejection. If the op amp is operating inverting, there is no common mode induced distortion. If the op amp is operating in the PNP input stage (input not within 1V of V +), the CMRR is very good, typically 95dB. When the LT1784 switches between input stages, there is significant nonlinearity in the CMRR. Lower load resistance increases the output crossover distortion but has no effect on the input stage transition distortion. For lowest distortion, the LT1784 should be operated single supply, with the output always sourcing current and with the input voltage swing between ground and (V + – 1V). See Typical Performance Characteristics Curve, “Total Harmonic Distortion + Noise vs Output Voltage Amplitude.” Gain The open-loop gain is almost independent of load when the output is sourcing current. This optimizes performance in single supply applications where the load is returned to ground. The Typical Performance Characteric Curve “Open-Loop Gain” for various loads shows the details.
W
UU
9
LT1784
APPLICATIO S I FOR ATIO
Shutdown
The 6-lead part includes a shutdown feature that disables the part, reducing quiescent current and making the output high impedance. The part can be shut down by
TYPICAL APPLICATIO S
Adjustable Clamp Negative Rectifier
V+
LT1784
OUT
- ~80mV VIN
–
V–
10k WORKS WELL TO 100kHz
+
LT1784 VOUT 10k V–
V– VCLAMP - ~80mV WORKS WELL TO 100kHz
–
SI PLIFIED SCHE ATIC
Q1 D1 SHDN R1 6k Q4 – IN R6 1.5k J1 R2 1k
Q2
Q3 Q22 D3
R7 1.5k Q12 Q16
Q17 Q20 OUT Q18
+
20µA +IN
R3 1k
Q7 R8 0.75k
Q8 R9 0.75k Q10
Q11
Q15 Q13 Q14 Q21
Q26
Q9
Q25 Q23
Q24
Q5
Q6
D4
D5
R4 2k
R5 2k V–
1784 SS
10
+
VIN
+
LT1784 VCLAMP
–
U
bringing the SHDN pin 1.2V or more above V –. When shut down, the supply current is less than 1µA (V – ≤ VOUT ≤ V +). In normal operation, the SHDN pin can be tied to V – or left floating. See Typical Performance Characteristics Curve, “Supply Current vs SHDN pin Voltage.”
1784 TA07
W
U
W
UU
W
V+
Q19
LT1784
PACKAGE DESCRIPTIO
A A1 A2 L
SOT-23 (Original) .90 – 1.45 (.035 – .057) .00 – .15 (.00 – .006) .90 – 1.30 (.035 – .051) .35 – .55 (.014 – .021)
SOT-23 (ThinSOT) 1.00 MAX (.039 MAX) .01 – .10 (.0004 – .004) .80 – .90 (.031 – .035) .30 – .50 REF (.012 – .019 REF)
2.60 – 3.00 (.102 – .118)
.20 (.008) DATUM ‘A’ A A2
L
.09 – .20 (.004 – .008) (NOTE 2)
SOT-23 (Original) A A1 A2 L .90 – 1.45 (.035 – .057) .00 – 0.15 (.00 – .006) .90 – 1.30 (.035 – .051) .35 – .55 (.014 – .021)
SOT-23 (ThinSOT) 1.00 MAX (.039 MAX) .01 – .10 (.0004 – .004) .80 – .90 (.031 – .035) .30 – .50 REF (.012 – .019 REF) 2.60 – 3.00 (.102 – .118) 1.50 – 1.75 (.059 – .069) (NOTE 3) PIN ONE ID
.20 (.008) DATUM ‘A’ A A2
L
.09 – .20 (.004 – .008) (NOTE 2)
Information furnished by Linear Technology Corporation is believed to be accurate and reliable. However, no responsibility is assumed for its use. Linear Technology Corporation makes no representation that the interconnection of its circuits as described herein will not infringe on existing patent rights.
U
S5 Package 5-Lead Plastic SOT-23
(Reference LTC DWG # 05-08-1633) (Reference LTC DWG # 05-08-1635)
2.80 – 3.10 (.110 – .118) (NOTE 3) 1.50 – 1.75 (.059 – .069) (NOTE 3) PIN ONE .95 (.037) REF .25 – .50 (.010 – .020) (5PLCS, NOTE 2) NOTE: 1. CONTROLLING DIMENSION: MILLIMETERS MILLIMETERS 2. DIMENSIONS ARE IN (INCHES) 3. DRAWING NOT TO SCALE 4. DIMENSIONS ARE INCLUSIVE OF PLATING 5. DIMENSIONS ARE EXCLUSIVE OF MOLD FLASH AND METAL BURR 6. MOLD FLASH SHALL NOT EXCEED .254mm 7. PACKAGE EIAJ REFERENCE IS: SC-74A (EIAJ) FOR ORIGINAL JEDEC MO-193 FOR THIN 1.90 (.074) REF A1
S5 SOT-23 0401
S6 Package 6-Lead Plastic SOT-23
(Reference LTC DWG # 05-08-1634) (Reference LTC DWG # 05-08-1636)
2.80 – 3.10 (.110 – .118) (NOTE 3)
.95 (.037) REF
.25 – .50 (.010 – .020) (6PLCS, NOTE 2)
NOTE: 1. CONTROLLING DIMENSION: MILLIMETERS MILLIMETERS 2. DIMENSIONS ARE IN (INCHES) 3. DRAWING NOT TO SCALE 4. DIMENSIONS ARE INCLUSIVE OF PLATING 5. DIMENSIONS ARE EXCLUSIVE OF MOLD FLASH AND METAL BURR 6. MOLD FLASH SHALL NOT EXCEED .254mm 7. PACKAGE EIAJ REFERENCE IS: SC-74A (EIAJ) FOR ORIGINAL JEDEC MO-193 FOR THIN
1.90 (.074) REF
A1
S6 SOT-23 0401
11
LT1784
TYPICAL APPLICATIO S
Protected Fault Conditions
–18V 5V 5V 5V
+ –
V+ LT1784
REVERSE BATTERY
INPUT OVERVOLTAGE
INPUT DIFFERENTIAL VOLTAGE
INPUTS BELOW GROUND
Simple Peak Detector
5V VIN
Single Supply Full Wave Rectifier
1k OUT
+
LT1784
–
BAT54
ACCURACY 98% 90% 3dB
BANDWIDTH 3kHz TO 5.7kHz 116Hz TO 47kHz 34Hz TO 96kHz
5V 1k 1k IN
–
LT1784
VOUT 1µF VIN = 3VP-P, VCM = 2.5V 100k
1784 TA04
+
WORKS WELL TO 15kHz
1785 TA05
Simple Polarity Selector
1k V+ 1k IN
IN 1V/DIV OUT 1V/DIV
0V V–
1785 TA06a
–
LT1784
+
V–
SHDN
OUT FOLLOW INVERT
SHDN 5V/DIV 100µs/DIV VS = ± 5V VIN = 3VP-P AT 5kHz
1785 TA06b
RELATED PARTS
PART NUMBER LT1782 LT1783 LT1797 LT1637 LT1638/LT1639 LT1880 DESCRIPTION Micropower Over-The-Top Rail-to-Rail In/Out Op Amp in SOT-23 1.25MHz Over-The-Top Rail-to-Rail In/Out Op Amp in SOT-23 10MHz Rail-to-Rail In/Out Op Amp in SOT-23 1.1MHz Over-The-Top Rail-to-Rail In/Out Op Amp Dual/Quad 1.2MHz Over-The-Top Rail-to-Rail In/Out Op Amp SOT-23 Pico Amp Input, Precision, Rail-to-Rail Output Op Amp COMMENTS 55µA Max Supply Current, 800µV Max Offset Voltage 300µA Max Supply Current, 800µV Max Offset Voltage Unity-Gain Stable, 2.25µV/µs Slew Rate Micropower, 0.4V/µs Slew Rate Micropower 230µA Max, 0.4V/µs Slew Rate 150µV Offset, 900pA Bias Current
1784f LT/TP 0601 2K • PRINTED IN USA
12
Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900 q FAX: (408) 434-0507 q www.linear.com
© LINEAR TECHNOLOGY CORPORATION 2000
+
24V
U
+ + –
V+ LT1784 18V
+
+
LT1784
+
LT1784
–
10V
–
1784 TA02
BAT54