LT1784
1
1784fa
TYPICAL APPLICATION
DESCRIPTION
2.5MHz, Over-The-Top
Low Power, Rail-to-Rail Input
and Output Op Amp in SOT-23
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 amplifi er 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-Top
®
opera-
tion 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.
Programmable Gain, AV = 2, AV = 20, 100kHz Amplifi er
FEATURES
APPLICATIONS
n Operates with Inputs Above V+
n Rail-to-Rail Input and Output
n Gain Bandwidth Product: 2.5MHz
n Slew Rate: 2.1V/µs
n Low Input Offset Voltage: 3.5mV Max
n High Voltage Gain: 1000V/mV
n Single Supply Input Range: 0V to 18V
n Specifi ed on 3V, 5V and ±5V Supplies
n Reverse Battery Protection to 18V
n Low Power: 750µA Supply Current Max
n Output Shutdown on 6-Lead Version
n High Output Current: 15mA Min
n Operating Temperature Range: –40°C to 85°C
n Low Profi le (1mm) ThinSOT™ Package
n Portable Instrumentation
n Battery-Powered Systems
n Sensor Conditioning
n Supply Current Sensing
n MUX Amplifi ers
n 4mA to 20mA Transmitters L, LT, LTC, LTM, Linear Technology, the Linear logo and Over-The-Top are registered
trademarks of Linear Technology Corporation. ThinSOT is a trademark of Linear Technology
Corporation. All other trademarks are the property of their respective owners.
Programmable Gain Amplifi er
Frequency Response
–
+
LT1782
VCC
SHDN
IN
OUT
1784 TA01a
VEE
R2
9.09k
R1
10k
R3
1k
–
+
LT1784
VCC
VCC
AV = 2AV = 20
SHDN
VEE
()
AV = 1+ R1 + R2
R3
()
OR 1+ R1
R2 + R3
FREQUENCY (Hz)
GAIN (dB)
30
25
20
15
10
5
0
–5
–10
–15
–201k 100k 1M 10M
1784 TA01b
10k
AV = 20
AV = 2
LT1784
2
1784fa
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) ............ Indefi nite
(Note 1)
4
5
3
1
OUT
V–
+IN
V+
–IN
TOP VIEW
S5 PACKAGE
5-LEAD PLASTIC TSOT-23
2
+–
TJMAX = 150°C, θJA = 250°C/W
1
2
3
6
5
4
TOP VIEW
S6 PACKAGE
6-LEAD PLASTIC TSOT-23
OUT
V–
+IN
V+
SHDN
–IN
+–
TJMAX = 150°C, θJA = 230°C/W
PIN CONFIGURATION
ORDER INFORMATION
LEAD FREE FINISH TAPE AND REEL PART MARKING PACKAGE DESCRIPTION SPECIFIED TEMPERATURE RANGE
LT1784CS5#PBF LT1784CS5#TRPBF LTJD 5-Lead Plastic TSOT-23 –40°C to 85°C
LT1784IS5#PBF LT1784IS5#TRPBF LTSN 5-Lead Plastic TSOT-23 –40°C to 85°C
LT1784CS6#PBF LT1784CS6#TRPBF LTIW 6-Lead Plastic TSOT-23 –40°C to 85°C
LT1784IS6#PBF LT1784IS6#TRPBF LTIX 6-Lead Plastic TSOT-23 –40°C to 85°C
Consult LTC Marketing for parts specifi ed with wider operating temperature ranges.
Consult LTC Marketing for information on non-standard lead based fi nish parts.
For more information on lead free part marking, go to: http://www.linear.com/leadfree/
For more information on tape and reel specifi cations, go to: http://www.linear.com/tapeandreel/
Operating Temperature Range (Note 10)..–40°C to 85°C
Specifi ed 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
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
VOS Input Offset Voltage TA = 25°C
0°C ≤ TA ≤ 70°C
–40°C ≤ TA ≤ 85°C
l
l
1.5 3.5
4.2
4.5
mV
mV
mV
ΔVOS/ΔTInput Offset Voltage Drift (Note 7) –40°C ≤ TA ≤ 85°C l5 15 µV/°C
IOS Input Offset Current
VCM = 18V (Note 3)
l
l
25 50
50
nA
µA
ELECTRICAL CHARACTERISTICS
The l denotes the specifi cations which apply over the specifi ed
temperature range, otherwise specifi cations are at 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 specifi ed.
LT1784
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ELECTRICAL CHARACTERISTICS
The l denotes the specifi cations which apply over the specifi ed
temperature range, otherwise specifi cations are at 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 specifi ed.
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
IBInput Bias Current
VCM = 18V (Note 3)
SHDN or VS = 0V, VCM = 0V to 18V
l
l
250
225
0.1
500
400
nA
µA
nA
ΔIB/ΔTInput Bias Current Drift –40°C ≤ TA ≤ 85°C l0.4 nA/°C
Input Noise Voltage 0.1Hz to 10Hz 1.5 µVP-P
enInput Noise Voltage Density f = 10kHz 25 nV/√Hz
inInput Noise Current Density f = 10kHz 0.3 pA/√Hz
RIN Input Resistance Differential
Common Mode, VCM = 0V to (VCC – 1.2V)
Common Mode, VCM = 0V to 18V
100
45
200
150
80
k
M
k
CIN Input Capacitance 5pF
VCM Input Voltage Range l018V
CMRR Common Mode Rejection Ratio
(Note 3)
VCM = 0V to VCC – 1.2V
VCM = 0V to 18V (Note 6)
l
l
84
60
95
70
dB
dB
PSRR Power Supply Rejection Ratio VS = 3V to 12.5V, VCM = VO = 1V l90 100 dB
AVOL Large-Signal Voltage Gain VS = 3V, VO = 500mV to 2.5V, RL = 10k
VS = 3V, 0°C ≤ TA ≤ 70°C
VS = 3V, –40°C ≤ TA ≤ 85°C
l
l
133
90
60
1000 V/mV
V/mV
V/mV
VS = 5V, VO = 500mV to 4.5V, RL = 10k
VS = 5V, 0°C ≤ TA ≤ 70°C
VS = 5V, –40°C ≤ TA ≤ 85°C
l
l
266
180
120
1000 V/mV
V/mV
V/mV
VOL Output Voltage Swing LOW No Load
ISINK = 5mA
VS = 5V, ISINK = 10mA
l
l
l
4
200
350
10
400
600
mV
mV
mV
VOH Output Voltage Swing HIGH VS = 3V, No Load
VS = 3V, ISOURCE = 3mA
l
l
2.885
2.600
2.93
2.8
V
V
VS = 5V, No Load
VS = 5V, ISOURCE = 10mA
l
l
4.885
4.400
4.93
4.7
V
V
ISC Short-Circuit Current (Note 2) VS = 3V, Short to GND
VS = 3V, Short to VCC
4
15
7.5
30
mA
mA
VS = 5V, Short to GND
VS = 5V, Short to VCC
12.5
20.0
22
40
mA
mA
Minimum Supply Voltage l2.5 2.7 V
Reverse Supply Voltage IS = –100µA l18 V
ISSupply Current
(Note 4) l
500 750
900
µA
µA
Supply Current, Shutdown VPIN5 = 2V, No Load (Note 8) l718 µA
ISHDN SHDN Pin Current VPIN5 = 0.3V (On), No Load (Note 8)
VPIN5 = 2V (Shutdown), No Load (Note 8)
VPIN5 = 5V (Shutdown), No Load (Note 8)
l
l
0.5
2.0
5.0
8
nA
µA
µA
Output Leakage Current, Shutdown VPIN5 = 2V, No Load (Note 8) l0.05 1 µA
Maximum SHDN Pin Current VPIN5 = 18V, No Load (Note 8) l10 30 µA
VIL SHDN Pin Input Low Voltage (Note 8) l0.3 V
VIH SHDN Pin Input High Voltage (Note 8) l2V
tON Turn-On Time VPIN5 = 5V to 0V, RL = 10k (Note 8) 18 µs
tOFF Turn-Off Time VPIN5 = 0V to 5V, RL = 10k (Note 8) 2.2 µs
LT1784
4
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ELECTRICAL CHARACTERISTICS
The l denotes the specifi cations which apply over the specifi ed
temperature range, otherwise specifi cations are at 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 specifi ed.
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
GBW Gain Bandwidth Product
(Note 4)
f = 5kHz
0°C ≤ TA ≤ 70°C
–40°C ≤ TA ≤ 85°C
l
l
1.5
1.2
1.1
2.5 MHz
MHz
MHz
SR Slew Rate
(Note 5) AV = –1, RL = ∞
0°C ≤ TA ≤ 70°C
–40°C ≤ TA ≤ 85°C
l
l
1.2
1.1
1.0
2.1 V/µs
V/µs
V/µs
FPBW Full-Power Bandwidth (Note 9) VOUT = 2VP-P 350 kHz
tSSettling Time VS = 5V, ΔVOUT = 2V to 0.1%, AV = –1 3.7 µs
THD Distortion VS = 3V, VO = 1.8VP-P
, AV = 1, RL = 10k, f = 1kHz 0.001 %
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
VOS Input Offset Voltage TA = 25°C
0°C ≤ TA ≤ 70°C
–40°C ≤ TA ≤ 85°C
l
l
1.6 3.75
4.50
4.80
mV
mV
mV
ΔVOS/ΔTInput Offset Voltage Drift (Note 7) –40°C ≤ TA ≤ 85°C l515µV/°C
IOS Input Offset Current l25 50 nA
IBInput Bias Current l250 500 nA
ΔIB/ΔTInput Bias Current Drift 0°C ≤ TA ≤ 70°C l0.4 nA/°C
Input Noise Voltage 0.1Hz to 10Hz 1.5 µVP-P
enInput Noise Voltage Density f = 1kHz 25 nV/√Hz
inInput Noise Current Density f = 1kHz 0.3 pA/√Hz
RIN Input Resistance Differential
Common Mode, VCM = –5V to 13V
l
l
100
45
200
80
k
k
CIN Input Capacitance 5pF
VCM Input Voltage Range l–5 13 V
CMRR Common Mode Rejection Ratio VCM = –5V to 13V l60 70 dB
AVOL Large-Signal Voltage Gain VO = ±4V, RL = 10k
0°C ≤ TA ≤ 70°C l
50
35
100 V/mV
V/mV
VOL Output Voltage Swing LOW No Load
ISINK = 5mA
ISINK = 10mA
l
l
l
–4.996
–4.800
–4.650
–4.99
–4.60
–4.40
V
V
V
VOH Output Voltage Swing HIGH No Load
ISOURCE = 5mA
ISOURCE = 10mA
l
l
l
4.885
4.550
4.400
4.92
4.75
4.65
V
V
V
ISC Short-Circuit Current (Note 2) Short to GND
0°C ≤ TA ≤ 70°C l
15
10
27 mA
mA
PSRR Power Supply Rejection Ratio VS = ±1.5V to ±9V l90 100 dB
ISSupply Current
l
540 800
975
µA
µA
Supply Current, Shutdown VPIN5 = –3V, VS = ±5V, No Load (Note 8) l820 µA
ISHDN SHDN Pin Current VPIN5 = –4.7V (On), VS = ±5V, No Load (Note 8)
VPIN5 = –3V (Shutdown), VS = ±5V, No Load (Note 8)
l
l
0.5
2.0 8
nA
µA
Maximum SHDN Pin Current VPIN5 = 9V, VS = ±9V (Note 8) l10 30 µA
Output Leakage Current, Shutdown VPIN5 = –7V, VS = ±9V, No Load (Note 8) l0.05 1 µA
The l denotes the specifi cations which apply over the specifi ed temperature range, otherwise specifi cations are at TA = 25°C.
VS = ±5V, VCM = 0V, VOUT = 0V, for the 6-lead part VPIN5 = V–, pulse power tested unless otherwise specifi ed.
LT1784
5
1784fa
ELECTRICAL CHARACTERISTICS
The l denotes the specifi cations which apply over the specifi ed
temperature range, otherwise specifi cations are at TA = 25°C. VS = ±5V, VCM = 0V, VOUT = 0V, for the 6-lead part VPIN5 = V–,
pulse power tested unless otherwise specifi ed.
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
VIL SHDN Pin Input Low Voltage VS = ±5V (Note 8) l–4.7 V
VIH SHDN Pin Input High Voltage VS = ±5V (Note 8) l–3 V
tON Turn-On Time VPIN5 = 0V to –5V, RL = 10k (Note 8) l18 µs
tOFF Turn-Off Time VPIN5 = –5V to 0V, RL = 10k (Note 8) l2.2 µs
GBW Gain Bandwidth Product f = 5kHz
0°C ≤ TA ≤ 70°C
–40°C ≤ TA ≤ 85°C
l
l
1.55
1.30
1.20
2.6 MHz
MHz
MHz
SR Slew Rate AV = –1, RL = ∞, VO = ±4V, Measured at VO = ±2V
0°C ≤ TA ≤ 70°C
–40°C ≤ TA ≤ 85°C
l
l
1.3
1.2
1.1
2.2 V/µs
V/µs
V/µs
FPBW Full-Power Bandwidth (Note 9) VOUT = 8VP-P 94 kHz
tSSettling Time VS = 5V, ΔVOUT = 4V to 0.1%, AV = 1 3.4 µs
Note 1: Stresses beyond those listed under Absolute Maximum Ratings
may cause permanent damage to the device. Exposure to any Absolute
Maximum Rating condition for extended periods may affect device
reliability and lifetime.
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 specifi cation 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: Specifi cations 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 specifi ed performance from
0°C to 70°C. The LT1784C is designed, characterized and expected to
meet specifi ed performance from –40°C to 85°C but is not tested or QA
sampled at these temperatures. LT1784I is guaranteed to meet specifi ed
performance from –40°C to 85°C.
Supply Current vs Supply Voltage Minimum Supply Voltage
Output Voltage
vs Large Input Voltage
TYPICAL PERFORMANCE CHARACTERISTICS
SUPPLY VOLTAGE (V)
24 8 12 16
SUPPLY CURRENT (µA)
18
1784 G01
610 14
700
650
600
550
500
450
400
350
300
TA = 125°C
TA = 25°C
TA = –55°C
TOTAL SUPPLY VOLTAGE (V)
1
INPUT OFFSET VOLTAGE CHANGE (µV)
5
1784 G02
234
400
300
200
100
0
–100
–200
–300
–400
TA = 125°C
TA = 25°C
TA = –55°C
VIN (V)
–10
VOUT (V)
5
4
3
2
1
0–2 610
1784 G03
–6 214 18
VS = 5V, 0V
+
–
5V
VIN
LT1784
6
1784fa
TYPICAL PERFORMANCE CHARACTERISTICS
Output Saturation Voltage
vs Input Overdrive
Output Short-Circuit Current
vs Temperature 0.1Hz to 10Hz Noise Voltage
Noise Voltage Density
vs Frequency Input Noise Current vs Frequency
Gain and Phase Shift
vs Frequency
Input Bias Current
vs Common Mode Voltage
Output Saturation Voltage
vs Load Current (Output High)
Output Saturation Voltage
vs Load Current (Output Low)
COMMON MODE VOLTAGE (V)
3.5
INPUT BIAS CURRENT (nA)
300,000
250,000
200,000
150,000
100,000
800
600
400
200
0
–200
–400 44.5 5 5.5
1784 G04
14 1816
TA = 125°C
VS = 5V, 0V
TA = 25°C
TA = –55°C
SOURCING LOAD CURRENT (µA)
1
0.01
OUTPUT SATURATION VOLTAGE (V)
0.1
1
100 10000
1784 G05
10 1000
TA = 125°C
TA = 25°C
TA = –55°C
VS = ±2.5V
VOD = 30mV
SINKING LOAD CURRENT (µA)
OUTPUT SATURATION VOLTAGE (V)
1 100 1000 10000
1784 G06
10
1
0.1
0.01
0.001
TA = 125oC
TA = –55oC
TA = 25oC
VS = p2.5V
VOD = 30mV
INPUT OVERDRIVE (mV)
0
1
OUTPUT SATURATION VOLTAGE (mV)
10
100
10 20 30 40 50 60
1784 G07
VS = ±2.5V
NO LOAD
OUTPUT HIGH
OUTPUT LOW
TEMPERATURE (°C)
–50
OUTPUT CURRENT (mA)
50
45
40
35
30
25 050 100
1784 G08
–25 25 125
75
SINKING
SOURCING
VS = ±5V
TIME (sec)
013579
NOISE VOLTAGE (400nV/DIV)
2468
1784 G09
10
VS = ±2.5V
FREQUENCY (Hz)
INPUT NOISE VOLTAGE DENSITY (nV/√Hz)
100
90
80
70
60
50
40
30
20
10
01 100 1k 100k
1784 G10
10 10k
VS = ±2.5V
FREQUENCY (Hz)
INPUT NOISE CURRENT DENSITY (pA/√Hz)
1 100 1k 100k
1784 G11
10 10k
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0
VS = ±2.5V
FREQUENCY (Hz)
GAIN (dB)
PHASE (DEG)
70
60
50
40
30
20
10
0
–10
–20
–30
120
100
80
60
40
20
0
–20
–40
–60
–80
1784 G12
1k 10k 100k 1M 10M
VS = ±2.5V
PHASE
GAIN
LT1784
7
1784fa
TYPICAL PERFORMANCE CHARACTERISTICS
Gain Bandwidth and Phase
Margin vs Load Resistance PSRR vs Frequency CMRR vs Frequency
Output Impedance vs Frequency
Disabled Output Impedance
vs Frequency
Settling Time to 0.1%
vs Output Step
Gain Bandwidth Product
vs Temperature Slew Rate vs Temperature
Gain Bandwidth Product and
Phase Margin vs Supply Voltage
TEMPERATURE (°C)
–50
GAIN BANDWIDTH PRODUCT (MHz)
2.8
2.7
2.6
2.5
2.4
2.3
2.2 25 75
1784 G13
–25 0 50 100 125
VS = ±2.5V
f = 5kHz
TEMPERATURE (°C)
–50
SLEW RATE (V/µs)
3.0
2.5
2.0
1.5 25 75
1784 G14
–25 0 50 100 125
RISING
FALLING
VS = ±5V
TOTAL SUPPLY VOLTAGE (V)
0
GAIN BANDWIDTH PRODUCT (MHz)
4810 18
1784 G15
26 12 14 16
2.7
2.6
2.5
2.4
PHASE MARGIN (DEG)
AV = –1
RF = RG = 10k
f = 5kHz
PHASE MARGIN
GAIN BANDWIDTH
PRODUCT
65
60
55
LOAD RESISTANCE ()
1k
GAIN BANDWIDTH PRODUCT (MHz)
PHASE MARGIN (DEG)
2.6
2.4
2.2
2.0 10k 100k
1784 G16
VS = ±2.5V
AV = –1
RF = RG = 10k
f = 5kHz
65
60
55
PHASE MARGIN
GAIN BANDWIDTH
PRODUCT
FREQUENCY (Hz)
1k
POWER SUPPLY REJECTION RATIO (dB)
90
80
70
60
50
40
30
20
10
0
–10 10k 100k 1M
1784 G17
POSITIVE SUPPLY
NEGATIVE SUPPLY
VS = ±2.5V
FREQUENCY (Hz)
10k
COMMON MODE REJECTION RATIO (dB)
120
110
100
90
80
70
60
50
40
30
20 100k 1M
1784 G18
VS = ±2.5V
FREQUENCY (Hz)
OUTPUT IMPEDANCE (Ω)
100 10k 100k 1M
1784 G19
1k
1k
100
10
1
0.1
0.01
AV = 100
AV = 10
AV = 1
VS = ±2.5V
FREQUENCY (Hz)
1k
OUTPUT IMPEDANCE (Ω)
10k
100k
1M
100 10k 100k
1784 G20
100 1k 1M
VS = ±2.5V
VPIN 5 = 2.5V
SETTLING TIME (µs)
0
OUTPUT STEP (V)
5
4
3
2
1
0
–1
–2
–3
–4
–5 245
1784 G21
13 678
VS = ±5V
AV = –1
AV = –1
AV = 1
AV = 1
LT1784
8
1784fa
TYPICAL PERFORMANCE CHARACTERISTICS
Total Harmonic Distortion + Noise
vs Load Resistance
Total Harmonic Distortion + Noise
vs Output Voltage Amplitude Open-Loop Gain
Supply Current
vs SHDN Pin Voltage Large Signal Response Small Signal Response
Capacitive Load Handling
Overshoot vs Capacitive Load
Undistorted Output Swing
vs Frequency
Total Harmonic Distortion + Noise
vs Frequency
CAPACITIVE LOAD (pF)
10
OVERSHOOT (%)
70
60
50
40
30
20
10
0100 1000
1784 G22
VS = 5V, 0V
VCM = 2.5V AV = 1
AV = 5
AV = 10
FREQUENCY (Hz)
1k
OUTPUT SWING (VP-P)
12
10
8
6
4
2
010k 100k 1M
1784 G23
DISTORTION ≤ 1%
AV = 1
VS = ±5V
VS = ±2.5V
FREQUENCY (Hz)
THD + NOISE (%)
10 1k 10k 100k
1784 G24
100
0.1
0.01
0.001
0.0001
RL = 10k
VS = 3V, 0V
VOUT = 1.8VP-P
VCM = 1V
AV = –1
AV = 1
OUTPUT VOLTAGE AMPLITUDE (VP-P)
0.01
THD + NOISE (%)
0.1
1
10
023
0.001 1
1784 G26
FREQUENCY = 1kHz
VCM = HALF SUPPLY
AV = –1
VS = 3V, 0V
RF = RG = 10k
AV = 1
VS = 3V, 0V
AV = 1
VS = ±1.5V
AV = –1
VS = ±1.5V
RF = RG = 10k
LOAD RESISTANCE TO GROUND ()
0.001
THD + NOISE (%)
0.01
0.1
1
100 10k 100k
1784 G25
0.0001 1k
VS = ±1.5V
VIN = ±1V
AV = 1
VS = 3V TOTAL
VIN = 2VP-P AT 1kHz
VS = 3V, 0V
VIN = 0.1V TO 2.1V
OUTPUT VOLTAGE (V)
–6 –5 –4 –3 –2 –1
INPUT OFFSET VOLTAGE CHANGE (50µV/DIV)
2
1784 G27
01 3 5
46
RL = 2k
RL = 10k
RL = 50k
VS = ±5V
SHUTDOWN PIN VOLTAGE (V)
0
SUPPLY CURRENT (µA)
0.5 12.5
1784 G28
1.5 2
600
550
500
450
400
350
300
250
200
150
100
50
0
TA = 125°C
TA = –55°C
TA = 25°C
VS = 5V, 0V
VS = ±5V
AV = 1
CL = 15pF
2V/DIV
5µs/DIV 1784 G29 VS = ±5V
AV = 1
CL = 15pF
20mV/DIV
2µs/DIV 1784 G30
LT1784
9
1784fa
APPLICATIONS INFORMATION
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
Simplifi ed 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 transis-
tors 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.
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 section.
The LT1784 is internally compensated to drive at least
400pF of capacitance under any output loading condi-
tions. A 0.22µF capacitor in series with a 150Ω resistor
between the output and ground will compensate these
amplifi ers 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 non-
linear 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 signifi cant 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.
LT1784
10
1784fa
APPLICATIONS INFORMATION
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 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
fl oating. See Typical Performance Characteristics curve,
“Supply Current vs SHDN pin Voltage.”
TYPICAL APPLICATIONS
Negative Rectifi er Adjustable Clamp
–
+
–
+
LT1784
VIN
OUT
V–
V–
V–
V+
–
+
LT1 7 8 4
LT1784
VIN
VCLAMP
VCLAMP - ~80mV
VOUT
1784 TA02
10k
10k
WORKS WELL
TO 100kHz
WORKS WELL
TO 100kHz
- ~80mV
SIMPLIFIED SCHEMATIC
Q10
D5
Q9
Q1
Q7
R2
1k
R6
1.5k
R7
1.5k
R3
1k
R4
2k
R8
0.75k
R9
0.75k
Q8
Q5
–IN
+IN
Q11 Q12
D4
Q2
D1
Q6
Q13 Q14
R1
6k
R5
2k
Q4
Q15
Q19
D3
Q3
Q16 Q18
Q22
V+
Q17
Q20
Q21
OUT
V–
1784 SS
SHDN
20µA
+
Q23 Q24Q25
Q26
J1
LT1784
11
1784fa
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 representa-
tion that the interconnection of its circuits as described herein will not infringe on existing patent rights.
PACKAGE DESCRIPTION
S5 Package
5-Lead Plastic TSOT-23
(Reference LTC DWG # 05-08-1635 Rev B)
1.50 – 1.75
(NOTE 4)
2.80 BSC
0.30 – 0.45 TYP
5 PLCS (NOTE 3)
DATUM ‘A’
0.09 – 0.20
(NOTE 3) S5 TSOT-23 0302 REV B
PIN ONE
2.90 BSC
(NOTE 4)
0.95 BSC
1.90 BSC
0.80 – 0.90
1.00 MAX
0.01 – 0.10
0.20 BSC
0.30 – 0.50 REF
NOTE:
1. DIMENSIONS ARE IN MILLIMETERS
2. DRAWING NOT TO SCALE
3. DIMENSIONS ARE INCLUSIVE OF PLATING
4. DIMENSIONS ARE EXCLUSIVE OF MOLD FLASH AND METAL BURR
5. MOLD FLASH SHALL NOT EXCEED 0.254mm
6. JEDEC PACKAGE REFERENCE IS MO-193
3.85 MAX
0.62
MAX
0.95
REF
RECOMMENDED SOLDER PAD LAYOUT
PER IPC CALCULATOR
1.4 MIN
2.62 REF
1.22 REF
S6 Package
6-Lead Plastic TSOT-23
(Reference LTC DWG # 05-08-1636 Rev B)
1.50 – 1.75
(NOTE 4)
2.80 BSC
0.30 – 0.45
6 PLCS (NOTE 3)
DATUM ‘A’
0.09 – 0.20
(NOTE 3) S6 TSOT-23 0302 REV B
2.90 BSC
(NOTE 4)
0.95 BSC
1.90 BSC
0.80 – 0.90
1.00 MAX 0.01 – 0.10
0.20 BSC
0.30 – 0.50 REF
PIN ONE ID
NOTE:
1. DIMENSIONS ARE IN MILLIMETERS
2. DRAWING NOT TO SCALE
3. DIMENSIONS ARE INCLUSIVE OF PLATING
4. DIMENSIONS ARE EXCLUSIVE OF MOLD FLASH AND METAL BURR
5. MOLD FLASH SHALL NOT EXCEED 0.254mm
6. JEDEC PACKAGE REFERENCE IS MO-193
3.85 MAX
0.62
MAX
0.95
REF
RECOMMENDED SOLDER PAD LAYOUT
PER IPC CALCULATOR
1.4 MIN
2.62 REF
1.22 REF
LT1784
12
1784fa
Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com
© LINEAR TECHNOLOGY CORPORATION 2000
LT 0609 REV A • PRINTED IN USA
RELATED PARTS
TYPICAL APPLICATIONS
PART NUMBER DESCRIPTION COMMENTS
LT1782 Micropower Over-The-Top Rail-to-Rail In/Out Op Amp in SOT-23 55µA Max Supply Current, 800µV Max Offset Voltage
LT1783 1.25MHz Over-The-Top Rail-to-Rail In/Out Op Amp in SOT-23 300µA Max Supply Current, 800µV Max Offset Voltage
LT1797 10MHz Rail-to-Rail In/Out Op Amp in SOT-23 Unity-Gain Stable, 2.25µV/µs Slew Rate
LT1637 1.1MHz Over-The-Top Rail-to-Rail In/Out Op Amp Micropower, 0.4V/µs Slew Rate
LT1638/LT1639 Dual/Quad 1.2MHz Over-The-Top Rail-to-Rail In/Out Op Amp Micropower 230µA Max, 0.4V/µs Slew Rate
LT1880 SOT-23 Pico Amp Input, Precision, Rail-to-Rail Output Op Amp 150µV Offset, 900pA Bias Current
Protected Fault Conditions
Simple Polarity Selector
Simple Peak Detector Simple Supply Full Wave Rectifi er
–
+
LT1784
–
+
LT1784
+–
+
LT1784
–
+
LT1784
+
+
REVERSE BATTERY INPUT DIFFERENTIAL VOLTAGE INPUTS BELOW GROUND
INPUT OVERVOLTAGE
–18V 5V 5V 5V
24V 10V
18V
V+V+
1784 TA03
ACCURACY
98%
90%
3dB
BANDWIDTH
3kHz TO 5.7kHz
116Hz TO 47kHz
34Hz TO 96kHz
–
+
1784 TA04
LT1784
BAT54
VOUT
VIN
1µF 100k
5V
VIN = 3VP-P, VCM = 2.5V
–
+LT1784
IN
1k
1k
1k
5V BAT54
OUT
WORKS WELL
TO 15kHz
1785 TA05
–
+
LT1784
IN
1k
1k
V+
V–
OUT
1785 TA06a
SHDN
INVERT
FOLLOW 0V
V–
IN
1V/DIV
OUT
1V/DIV
SHDN
5V/DIV
100µs/DIV
VS = ±5V
VIN = 3VP-P AT 5kHz
1785 TA06b
