LINER LT1673 Dual and quad over-the-top precision rail-to-rail input and output op amp Datasheet

LT1672/LT1673/LT1674
2µA Max, AV ≥ 5 Single, Dual
and Quad Over-The-Top Precision
Rail-to-Rail Input and Output Op Amps
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FEATURES
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DESCRIPTIO
Gain of 5 Stable
Low Supply Current: 2µA Max per Amplifier
Rail-to-Rail Input and Output
Low Offset Voltage: 375µV Max
Over-The-TopTM Inputs Operate Above V+
Gain Bandwidth Product: 12kHz
Wide Supply Range: 2.2V to 36V
Single Supply Input Range: – 0.3V to 36V
Low Input Bias Current: 250pA
Low Input Offset Current: 20pA
High AVOL: 100V/mV Minimum Driving 100kΩ Load
Output Sources and Sinks 500µA Load Current
Reverse Battery Protected to 18V
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APPLICATIO S
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The LT ®1672/LT1673/LT1674 are ultralow power
(IS ≤ 2µA) decompensated (AV ≥ 5) op amps with precision specifications. The extremely low supply current is
combined with excellent amplifier specifications: input
offset voltage is 375µV maximum with a typical drift of
only 0.4µV/°C, input offset current is 100pA maximum. A
minimum open-loop gain (AVOL) of 100V/mV ensures that
gain errors are small. The devices’ characteristics change
little over the supply range of 2.2V to ±15V. Supply
rejection is 90dB and the common mode rejection ratio is
90dB. Operation is specified for 3V, 5V and ±15V supplies.
Reverse battery protection (–18V min) and inputs that
operate above the positive supply make the LT1672/
LT1673/LT1674 easy to use in harsh environments.
The low bias currents and offset current of the amplifier
permit the use of megohm level source resistors without
introducing significant errors. Voltage noise at 4µVP-P is
remarkably low considering the low supply current. For
unity gain stable versions of these amplifiers, see the
LT1494/LT1495/LT1496.
Battery- or Solar-Powered Systems
Portable Instrumentation
Remote Sensor Amplifier
Micropower Filter
Photodiode Amplifier
High Impedance Circuits
The LT1672 is available in the 8-pin MSOP, PDIP and SO
packages. The LT1673 is available in plastic 8-pin PDIP
and SO-8 packages with the standard dual op amp pinout.
The LT1674 is available in 14-pin PDIP and SO packages.
, LTC and LT are registered trademarks of Linear Technology Corporation.
Over-The-Top is a trademark of Linear Technology Corporation.
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TYPICAL APPLICATION
TC VOS Distribution
Single Supply, 60µW Precision Instrumentation Amplifier
80
120 AMPLIFIERS
70 VS = ±2.5V
– 40°C to 85°C
5V
100k*
VIN1
+
1M
60
1/2 LT1673
–
1000pF
1M
100k
1M
100k
110k
–
100k*
VIN2
1/2 LT1673
UNITS
110k
50
5V
–
LT1672
30
VOUT
20
+
1M
10
1M
5V
0.0047µF
40
LT1389-2.5
+
1672/3/4 TA01
AV = 100
BANDWIDTH = 1kHz
CMRR = 65dB AT 120Hz
*500V TRANSIENT PROTECTION
TOTAL SUPPLY CURRENT = 12µA
0
–1.5
– 0.9
– 0.3
0.3
TC VOS (µV/°C)
0.9
1.5
1672/3/4 TA02
1
LT1672/LT1673/LT1674
W W
W
AXI U
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ABSOLUTE
RATI GS
(Note 1)
Total Supply Voltage (V + to V –) .............................. 36V
Differential Input Voltage ......................................... 36V
Input Current ...................................................... ±10mA
Output Short-Circuit Duration ....................... Continuous
Operating Temperature Range (Note 2) .. – 40°C to 85°C
Specified Temperature Range (Note 3) ... – 40°C to 85°C
Storage Temperature Range ................. – 65°C to 150°C
Junction Temperature ........................................... 150°C
Lead Temperature (Soldering, 10 sec).................. 300°C
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U
W
PACKAGE/ORDER I FOR ATIO
ORDER PART
NUMBER
TOP VIEW
NC
–IN
+IN
V–
1
2
3
4
8
7
6
5
NC
V+
OUT
NC
MS8 PACKAGE
8-LEAD PLASTIC MSOP
TJMAX = 150°C, θJA = 250°C/ W
LT1672CMS8
LT1672IMS8
MS8 PART MARKING
LTFH
LTFJ
ORDER PART
NUMBER
TOP VIEW
OUT A 1
8
–IN A 2
A
+IN A 3
V– 4
N8 PACKAGE
8-LEAD PDIP
V+
7
OUT B
6
–IN B
5
+IN B
B
S8 PACKAGE
8-LEAD PLASTIC SO
TJMAX = 150°C, θJA = 150°C/ W (N8)
TJMAX = 150°C, θJA = 190°C/ W (S8)
LT1673CN8
LT1673CS8
LT1673IN8
LT1673IS8
S8 PART MARKING
1673
1673I
ORDER PART
NUMBER
TOP VIEW
NC 1
8
NC
–IN 2
7
V+
+IN 3
6
OUT
V– 4
5
NC
N8 PACKAGE
8-LEAD PDIP
LT1672CN8
LT1672CS8
LT1672IN8
LT1672IS8
S8 PART MARKING
S8 PACKAGE
8-LEAD PLASTIC SO
1672
1672I
TJMAX = 150°C, θJA = 130°C/ W (N8)
TJMAX = 150°C, θJA = 190°C/ W (S8)
ORDER PART
NUMBER
TOP VIEW
14 OUT D
OUT A 1
–IN A 2
+IN A 3
A
D
V+ 4
+IN B 5
LT1674CN
LT1674CS
LT1674IN
LT1674IS
13 –IN D
12 +IN D
11 V –
B
C
10 +IN C
–IN B 6
9
–IN C
OUT B 7
8
OUT C
N PACKAGE
14-LEAD PDIP
S PACKAGE
14-LEAD PLASTIC SO
TJMAX = 150°C, θJA = 110°C/ W (N)
TJMAX = 150°C, θJA = 150°C/ W (S)
Consult factory for parts specified with wider operating temperature ranges.
ELECTRICAL CHARACTERISTICS
TA = 25°C, VS = 5V, 0V; VS = 3V, 0V; VCM = VO = half supply, unless otherwise noted.
SYMBOL
VOS
PARAMETER
Input Offset Voltage
IB
Input Bias Current
IOS
Input Offset Current
Input Noise Voltage
2
CONDITIONS
VS = 5V
VS = 3V
VS = 5V, MS8 Package
VS = 3V, MS8 Package
(Note 5)
VCM = 10V (Note 6)
(Note 5)
0.1Hz to 10Hz
MIN
TYP
150
200
150
200
250
180
20
4
MAX
375
475
475
575
1000
360
100
UNITS
µV
µV
µV
µV
pA
nA
pA
µVP-P
LT1672/LT1673/LT1674
ELECTRICAL CHARACTERISTICS
TA = 25°C, VS = 5V, 0V; VS = 3V, 0V; VCM = VO = half supply, unless otherwise noted.
SYMBOL
en
in
AVOL
PARAMETER
Input Noise Voltage Density
Input Noise Current Density
Large-Signal Voltage Gain
CMRR
Input Voltage Range
Common Mode Rejection Ratio
PSRR
VOL
VOH
ISC
IS
SR
GBW
CONDITIONS
f = 100Hz
f = 100Hz
VS = 5V, VO = 0.25V to 4.5V, RL = 100k
VS = 3V, VO = 0.25V to 2.5V, RL = 100k
MIN
100
50
0
90
74
90
VCM = 0V to 4V, VS = 5V
VCM = 0V to 10V, VS = 5V
VS = 2.2V to 12V, VCM = VO = 0.5V
Power Supply Rejection Ratio
Minimum Operating Supply Voltage
Output Voltage Swing LOW
No Load
ISINK = 100µA
Output Voltage Swing HIGH
No Load
ISOURCE = 100µA
Short-Circuit Current
(Note 5)
Supply Current per Amplifier
(Note 6)
Reverse Supply Voltage
IS = 10µA per Amplifier
Slew Rate
AV = – 5, VS = ±10V
Gain Bandwidth Product
f = 100Hz
V+ – 0.07
V+ – 0.32
0.7
–18
1.6
TYP
185
10
500
250
MAX
36
106
95
99
2.1
50
210
V+ – 0.035
V+ – 0.160
1.3
1.5
2.2
100
410
2
5
12
UNITS
nV/√Hz
fA/√Hz
V/mV
V/mV
V
dB
dB
dB
V
mV
mV
V
V
mA
µA
V
V/ms
kHz
The ● denotes the specifications which apply over the temperature range of 0°C ≤ TA ≤ 70°C. VS = 5V, 0V; VS = 3V, 0V;
VCM = VO = half supply, unless otherwise noted. (Note 3)
SYMBOL PARAMETER
Input Offset Voltage
VOS
VOS TC
IB
Input Offset Voltage Drift
Input Bias Current
IOS
AVOL
Input Offset Current
Large-Signal Voltage Gain
CMRR
Input Voltage Range
Common Mode Rejection Ratio
PSRR
VOL
Power Supply Rejection Ratio
Minimum Operating Supply Voltage
Output Voltage Swing LOW
VOH
Output Voltage Swing HIGH
ISC
IS
Short-Circuit Current
Supply Current per Amplifier
CONDITIONS
VS = 5V
VS = 3V
VS = 5V, MS8 Package
VS = 3V, MS8 Package
(Note 4)
(Note 5)
VCM = 10V (Note 6)
(Note 5)
VS = 5V, VO = 0.25V to 4.5V, RL = 100k
VS = 3V, VO = 0.25V to 2.5V, RL = 100k
MIN
●
●
●
●
●
●
●
●
●
●
●
VCM = 0.2V to 4V, VS = 5V
VCM = 0.2V to 10V, VS = 5V
VS = 2.4V to 12V, VCM = VO = 0.5V
●
●
●
75
40
0.2
89
64
89
●
No Load
ISINK = 100µA
No Load
ISOURCE = 100µA
(Note 5)
(Note 6)
●
●
●
●
●
●
V+ – 0.08
V+ – 0.36
0.6
TYP
175
225
175
225
0.4
250
240
20
280
150
MAX
425
525
525
625
2
1200
500
120
36
106
85
99
2.3
55
225
V+ – 0.04
V+ – 0.18
1.1
1.9
2.4
110
450
2.8
UNITS
µV
µV
µV
µV
µV/°C
pA
nA
pA
V/mV
V/mV
V
dB
dB
dB
V
mV
mV
V
V
mA
µA
3
LT1672/LT1673/LT1674
ELECTRICAL CHARACTERISTICS
The ● denotes the specifications which apply over the temperature range of – 40°C ≤ TA ≤ 85°C. VS = 5V, 0V; VS = 3V, 0V;
VCM = VO = half supply, unless otherwise noted. (Note 3)
SYMBOL PARAMETER
VOS
Input Offset Voltage
VOS TC
IB
Input Offset Voltage Drift
Input Bias Current
IOS
AVOL
Input Offset Current
Large-Signal Voltage Gain
CMRR
Input Voltage Range
Common Mode Rejection Ratio
PSRR
VOL
Power Supply Rejection Ratio
Minimum Operating Supply Voltage
Output Voltage Swing LOW
VOH
Output Voltage Swing HIGH
ISC
IS
Short-Circuit Current
Supply Current per Amplifier
CONDITIONS
VS = 5V
VS = 3V
VS = 5V, MS8 Package
VS = 3V, MS8 Package
(Note 4)
(Note 5)
VCM = 10V (Note 6)
(Note 5)
VS = 5V, VO = 0.25V to 4.5V, RL = 100k
VS = 3V, VO = 0.25V to 2.5V, RL = 100k
MIN
●
●
●
●
●
●
●
●
●
●
●
VCM = 0.2V to 4V, VS = 5V
VCM = 0.2V to 10V, VS = 5V
VS = 2.7V to 12V, VCM = VO = 0.5V
●
●
●
55
30
0.2
88
62
88
●
No Load
ISINK = 100µA
No Load
ISOURCE = 100µA
(Note 5)
(Note 6)
●
●
●
●
●
V+ – 0.10
V+ – 0.38
0.4
●
TYP
200
250
200
250
0.4
250
275
20
215
115
MAX
475
575
575
675
2
1700
750
170
36
106
75
99
2.6
60
245
V+ – 0.05
V+ – 0.19
0.9
2.1
2.7
120
490
3.1
UNITS
µV
µV
µV
µV
µV/°C
pA
nA
pA
V/mV
V/mV
V
dB
dB
dB
V
mV
mV
mV
mV
mA
µA
TA = 25°C, VS = ±15V, VCM = VO = 0V, unless otherwise noted.
SYMBOL PARAMETER
Input Offset Voltage
VOS
CONDITIONS
MIN
MS8 Package
IB
IOS
AVOL
CMRR
PSRR
VOL
Input Bias Current
Input Offset Current
Large-Signal Voltage Gain
Input Voltage Range
Common Mode Rejection Ratio
Power Supply Rejection Ratio
Output Voltage Swing LOW
VOH
Output Voltage Swing HIGH
ISC
IS
Short-Circuit Current
Supply Current per Amplifier
4
VO = ±10V, RL = 100k
VCM = – 15V to 14V
VS = ±5V to ±15V
RL = 1M
RL = 100k
RL = 1M
RL = 100k
100
– 15
100
96
14.78
14.62
0.7
TYP
200
200
25
20
360
MAX
575
675
1000
100
21
120
120
–14.85
–14.75
14.89
14.81
1.5
1.9
–14.70
–14.50
2.8
UNITS
µV
µV
pA
pA
V/mV
V
dB
dB
V
V
V
V
mA
µA
LT1672/LT1673/LT1674
ELECTRICAL CHARACTERISTICS
The ● denotes the specifications which apply over the temperature range of 0°C ≤ TA ≤ 70°C, VS = ±15V, VCM = VO = 0V,
unless otherwise noted. (Note 3)
SYMBOL PARAMETER
Input Offset Voltage
VOS
CONDITIONS
MS8 Package
IB
IOS
AVOL
CMRR
PSRR
VOL
Input Bias Current
Input Offset Current
Large-Signal Voltage Gain
Input Voltage Range
Common Mode Rejection Ratio
Power Supply Rejection Ratio
Output Voltage Swing LOW
VOH
Output Voltage Swing HIGH
ISC
IS
Short-Circuit Current
Supply Current per Amplifier
MIN
●
●
●
●
VO = ±10V, RL = 100k
●
●
VCM = –14.8V to 14V
VS = ±5V to ±15V
RL = 1M
RL = 100k
RL = 1M
RL = 100k
●
●
60
– 14.8
98
94
●
●
●
●
●
14.76
14.58
0.6
●
TYP
225
225
250
20
240
MAX
625
725
1200
120
21
120
120
–14.84
–14.73
14.88
14.79
1.3
2.4
–14.67
–14.46
3.5
UNITS
µV
µV
pA
pA
V/mV
V
dB
dB
V
V
V
mV
mA
µA
The ● denotes the specifications which apply over the temperature range of –40°C ≤ TA ≤ 85°C, VS = ±15V, VCM = VO = 0V,
unless otherwise noted. (Note 3)
SYMBOL PARAMETER
VOS
Input Offset Voltage
CONDITIONS
MS8 Package
IB
IOS
AVOL
CMRR
PSRR
VOL
Input Bias Current
Input Offset Current
Large-Signal Voltage Gain
Input Voltage Range
Common Mode Rejection Ratio
Power Supply Rejection Ratio
Output Voltage Swing LOW
VOH
Output Voltage Swing HIGH
ISC
IS
Short-Circuit Current
Supply Current per Amplifier
MIN
●
●
●
●
VO = ±10V, RL = 100k
●
●
VCM = –14.8V to 14V
VS = ±5V to ±15V
RL = 1M
RL = 100k
RL = 1M
RL = 100k
Note 1: Absolute Maximum Ratings are those values beyond which the life
of the device may be impaired.
Note 2: The LT1672C/LT1673C/LT1674C and LT1672I/LT1673I/LT1674I
are guaranteed functional over the Operating Temperature Range of – 40°C
to 85°C.
Note 3: The LT1672C/LT1673C/LT1674C are guaranteed to meet specified
performance from 0°C to 70°C. The LT1672C/LT1673C/LT1674C are
designed, characterized and expected to meet specified performance from
●
●
50
– 14.8
96
92
●
●
●
●
●
●
14.74
14.54
0.4
TYP
250
250
250
20
200
MAX
675
775
1700
170
21
114
120
–14.83
–14.72
14.87
14.77
1.1
2.8
–14.66
–14.44
4.2
UNITS
µV
µV
pA
pA
V/mV
V
dB
dB
V
V
V
V
mA
µA
– 40°C to 85°C but are not tested or QA sampled at these temperatures.
The LT1672I/LT1673I/LT1674I are guaranteed to meet specified
performance from – 40°C to 85°C.
Note 4: This parameter is not 100% tested.
Note 5: VS = 5V limit guaranteed by correlation to VS = 3V and VS = ±15V
tests.
Note 6: VS = 3V limit guaranteed by correlation to VS = 5V and VS = ±15V
tests.
5
LT1672/LT1673/LT1674
U W
TYPICAL PERFORMANCE CHARACTERISTICS
Distribution of Input
Offset Voltage
200
14
12
10
8
6
4
2
2.5
VS = ±15V
2.0
VS = ± 2.5V
1.5
1.0
0.5
0
–400 –300 –200 –100 0 100 200 300 400
INPUT OFFSET VOLTAGE (µV)
SATURATION VOLTAGE (mV)
SATURATION VOLTAGE (mV)
1000
TA = 85°C
TA = 25°C
TA = – 40°C
1
10
100
LOAD CURRENT (µA)
40
20
60
0
TEMPERATURE (°C)
1
100
TA = – 40°C
1.5
TA = 25°C
0.5
40
20
GAIN
0
20
–20
10
–40
0
–60
–80
10k
1672/3/4 G07
TA = – 40°C
–1 0
TA = 85°C
1 2 3 4 5 6 7 8
COMMON MODE VOLTAGE (V)
9 10
Noise Current Spectrum
100
VS = ± 2.5V
CURRENT NOISE (fA/√Hz)
40
NOISE VOLTAGE (nV/√Hz)
VOLTAGE GAIN (dB)
TA = 25°C
1672/3/4 G06
250
PHASE SHIFT (DEG)
60
50
6
300
100
30
TA = 85°C
200
– 0.5
1000
VS = 5V, 0V
1672/3/4 G05
80
1k
FREQUENCY (Hz)
Input Bias Current
vs Common Mode Voltage
TA = 25°C
10
100
LOAD CURRENT (µA)
5
1672/3/4 G03
TA = – 40°C
120
PHASE
3
2
4
TOTAL SUPPLY VOLTAGE (V)
1
Noise Voltage Spectrum
70
–10
100
0
300
TA = 85°C
10
0.1
1000
VS = ±2.5V
60
50
100
100
Gain and Phase Shift
vs Frequency
80
80
VS = 5V, 0V
1672/3/4 G04
90
TA = 85°C
Output Saturation Voltage
vs Load Current (Output High)
VS = 5V, 0V
10
0.1
TA = 25°C
TA = – 40°C
100
1672/3/4 G02
Output Saturation Voltage
vs Load Current (Output Low)
100
150
– 50
0
–40 –20
1672/73/74 G01
1000
CHANGE IN OFFSET VOLTAGE (µV)
PERCENT OF UNITS (%)
16
SUPPLY CURRENT PER AMPLIFIER (µA)
VS = 5V, 0V
LT1672/73/74
5600 AMPLIFIERS
18
Minimum Supply Voltage
Supply Current vs Temperature
3.0
INPUT BIAS CURRENT (nA)
20
200
150
100
50
0
VS = ± 2.5V
80
60
40
20
0
1
10
FREQUENCY (Hz)
100
1672/3/4 G08
1
10
FREQUENCY (Hz)
100
1672/3/4 G09
LT1672/LT1673/LT1674
U W
TYPICAL PERFORMANCE CHARACTERISTICS
Gain Bandwidth and Phase
Margin vs Supply Voltage
60
GBW
10
50
8
40
PHASE MARGIN (DEG)
12
VS = ±15V
VCM = 0V
70
PHASE MARGIN
Capacitive Load Handling
80
VS = ± 2.5V
70
60
OVERSHOOT (%)
MEASURED AT
AV = 5
14
FREQUENCY (kHz)
80
OUTPUT VOLTAGE (2µV/DIV)
16
0.1Hz to 10Hz
Output Voltage Noise
50
40
AV = 5
30
AV = 10
20
10
6
5
10
15
20
SUPPLY VOLTAGE (V)
25
30
30
0
TIME (1s/DIV)
1672/3/4 G10
Common Mode Rejection Ratio
vs Frequency
80
70
60
50
40
30
20
10
0
100
100
VS = ± 2.5V
90
80
70
+PSRR
60
50
40
–PSRR
30
20
10k 20k
100
1k
FREQUENCY (Hz)
10
1
10
OFFSET VOLTAGE CHANGE (µV)
VS = ±15V
10
VS = ±2.5V
–10
–20
–30
20 40 60 80 100 120 140 160 180 200
TIME AFTER POWER-UP (SEC)
1672/3/4 G16
10k
1672/3/4 G15
Open-Loop Gain
VS = ±15V
15
10
5
RL = 1M
0
RL = 100k
–5
–10
– 20
VS = ± 15V
VS = 5V, 0V
60
40
RL = 100k
20
0
RL = 1M
–20
– 40
– 60
–15
– 40
100
1k
FREQUENCY (Hz)
80
20
30
OFFSET VOLTAGE CHANGE (µV)
AV = 5
Open-Loop Gain
VS = 5V, 0V
40
0
10
1672/3/4 G14
Warm-Up Drift vs Time
0
AV = 10
0.1
10k
1672/3/4 G13
20
VS = ± 2.5V
10
0
1k
FREQUENCY (Hz)
10k
Output Impedance vs Frequency
100
OUTPUT IMPEDANCE (kΩ)
VS = ± 2.5V
90
100
1k
CAPACITIVE LOAD (pF)
1672/3/4 G12
Power Supply Rejection Ratio
vs Frequency
POWER SUPPLY REJECTION RATIO (dB)
COMMON MODE REJECTIO RATIO (dB)
100
10
1672/3/4 G07
OFFSET VOLTAGE CHANGE (µV)
0
0
1
2
4
3
OUTPUT VOLTAGE (V)
5
6
1672/3/4 G17
– 80
0
5
10
–20 –15 –10 –5
OUTPUT VOLTAGE (V)
15
20
1672/3/4 G18
7
LT1672/LT1673/LT1674
U W
TYPICAL PERFORMANCE CHARACTERISTICS
Small-Signal Response
VS = ±15V
CL = 100pF
AV = 5
1672/3/4 G19
Large-Signal Response
VS = 5V
CL = 100pF
AV = 5
1672/3/4 G20
VS = 5V
CL = 100pF
AV = 5
1672/3/4 G21
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Small-Signal Response
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APPLICATIO S I FOR ATIO
Start-Up Characteristics
V+
Micropower op amps are sometimes not micropower
during start-up, wreaking havoc on low current supplies.
In the worst case, there may not be enough supply current
available to take the system up to nominal voltages. Figure
1 is a graph of LT1673 supply current vs supply voltage
for the three limit cases of input offset that could occur
during start-up. The circuits are shown in Figure 2. One
circuit creates a positive offset, forcing the output to come
up saturated high. Another circuit creates a negative
offset, forcing the output to come up saturated low, while
the last brings up the output at half supply. In all cases, the
supply current is well behaved. Supply current is highest
with the output forced high, so if one amplifier is unused,
it is best to force the output low or at half supply.
SUPPLY CURRENT PER AMPLIFIER (µA)
5
4
OUTPUT HIGH
3
OUTPUT LOW
2
0
0
1
3
4
2
TOTAL SUPPLY VOLTAGE (V)
5
1672/3/4 FO1
Figure 1. Start-Up Characteristics
8
V+
+
+
+
–
–
–
820k
V–
V–
OUTPUT HIGH
OUTPUT LOW
200k
V–
16/2/3/4 F02
OUTPUT AT VS /2
Figure 2. Circuits for Start-Up Characteristics
Reverse Battery
The LT1672/LT1673/LT1674 are protected against reverse
battery voltages up to 18V. In the event a reverse battery
condition occurs, the supply current is typically less than
100nA (inputs grounded and outputs open). For typical
single supply applications with ground referred loads and
feedback networks, no other precautions are required. If
the reverse battery condition results in a negative voltage
at either the input pins or output pin, the current into the
pin should be limited by an external resistor to less than
10mA.
Inputs
OUTPUT VS/2
1
V+
While the LT1672/LT1673/LT1674 will function normally
with its inputs taken above the positive supply, the common mode range does not extend beyond approximately
300mV below the negative supply at room temperature.
LT1672/LT1673/LT1674
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W
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APPLICATIO S I FOR ATIO
The device will not be damaged if the inputs are taken lower
than 300mV below the negative supply as long as the current out of the pin is limited to less than 10mA. However,
the output phase is not guaranteed and the supply current
will increase.
and (VCC – 0.8V), Q1 and Q2 are active. When the input
common mode exceeds (VCC – 0.8V), Q7 turns on,
diverting the current from diff amp Q1-Q2 to current
mirror Q8-Q9. The current from Q8 biases on the other
diff amp consisting of PNP’s Q5-Q6 and NPN’s Q3-Q4.
Though Q5-Q6 are driven from the emitters rather than
the base, the basic diff amp action is the same. When the
common mode voltage is between (VCC – 0.8V) and VCC,
devices Q3 and Q4 act as followers, forming a buffer
between the amplifier inputs and the emitters of the Q5Q6. If the common mode voltage is taken above V CC,
Schottky diodes D1 and D2 reverse bias and devices Q3
and Q4 then act as diodes. The diff amp formed by Q5-Q6
operates normally, however, the input bias current increases to the emitter current of Q5-Q6, which is typically
180nA. The graph, Input Bias Current vs Common Mode
Voltage found in the Typical Performance Characteristics
section, shows these transitions at three temperatures.
Output
The graph, Capacitive Load Handling, shows amplifier stability with the output biased at half supply. If the output is
to be operated within about 100mV of the positive rail, the
allowable load capacitance is less. With this output voltage, the worst case occurs at AV = 5 and light loads, where
the load capacitance should be less than 500pF with a 5V
supply and less than 100pF with a 30V supply.
Rail-to-Rail Operation
The simplified schematic, Figure 3, details the circuit
design approach of the LT1672/LT1673/LT1674. The
amplifier topology is a three-stage design consisting of a
rail-to-rail input stage, that continues to operate with the
inputs above the positive rail, a folded cascode second
stage that develops most of the voltage gain, and a rail-torail common emitter stage that provides the current gain.
The collector currents of the two-input pairs are combined
in the second stage consisting of Q11 to Q16, which
furnishes most of the voltage gain. Capacitor C1 sets the
amplifier bandwidth. The output stage is configured for
maximum swing by the use of common emitter output
devices Q21 and Q22. Diodes D4 to D6 and current source
Q15 set the output quiescent current.
The input stage is formed by two diff amps Q1-Q2 and Q3Q6. For signals with a common mode voltage between V EE
D1
D2
D3
Q10
D7
Q13
Q14
Q15
Q20
+
I1
Q21
C1
IN +
IN –
OUT
Q1 Q2
Q3
Q4
Q7
Q16
Q17
Q11
Q6
Q5
(V +) – 0.8V
Q19
D4
Q12
D5
D6
Q18
Q9
Q8
R1
R2
Q22
I2
1672/3/4 F03
Figure 3. Simplified Schematic
9
LT1672/LT1673/LT1674
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TYPICAL APPLICATIO S
Battery Current Monitor
IL
CHARGE
Over-the-Top Comparator with Hysteresis
RSENSE
0.1Ω
1M
5V (VCC)
DISCHARGE
RA
RA
–
A2
1/2 LT1673
12V
5V
RA
IN1
(0V TO 12V)
–
10k
RA
+
VOUT
LT1672
A1
1/2 LT1673
–
+
1M
1M
+
2N5087
2N3904
DISCHARGE
OUT
2N3904
CHARGE
OUT
VO = IL
RB
()
RB
RSENSE
RA
10k
1M
2N5210
V
HYSTERESIS = CC
100
IS < 10µA
FOR RA = 10k, RB = 100k (RB/RA ≥5)
VO
= 1V/A
IL
1672/3/4 TA04
RB
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PACKAGE DESCRIPTIO
IN2
(0V TO 12V)
1672/3/4 TA03
Dimensions in inches (millimeters) unless otherwise noted.
MS8 Package
8-Lead Plastic MSOP
(LTC DWG # 05-08-1660)
0.043
(1.10)
MAX
0.007
(0.18)
0.034
(0.86)
REF
0.118 ± 0.004*
(3.00 ± 0.102)
8
7 6
5
0° – 6° TYP
0.021 ± 0.006
(0.53 ± 0.015)
SEATING
PLANE
0.009 – 0.015
(0.22 – 0.38)
0.0256
(0.65)
BSC
0.005 ± 0.002
(0.13 ± 0.05)
* DIMENSION DOES NOT INCLUDE MOLD FLASH, PROTRUSIONS OR GATE BURRS. MOLD FLASH,
PROTRUSIONS OR GATE BURRS SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE
** DIMENSION DOES NOT INCLUDE INTERLEAD FLASH OR PROTRUSIONS.
INTERLEAD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE
0.118 ± 0.004**
(3.00 ± 0.102)
0.193 ± 0.006
(4.90 ± 0.15)
1
2 3
MSOP (MS8) 1100
4
N8 Package
8-Lead PDIP (Narrow 0.300)
(LTC DWG # 05-08-1510)
0.300 – 0.325
(7.620 – 8.255)
0.009 – 0.015
(0.229 – 0.381)
(
+0.035
0.325 –0.015
8.255
+0.889
–0.381
)
0.045 – 0.065
(1.143 – 1.651)
0.130 ± 0.005
(3.302 ± 0.127)
0.065
(1.651)
TYP
8
7
6
5
1
2
3
4
0.255 ± 0.015*
(6.477 ± 0.381)
0.100
(2.54)
BSC
*THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS.
MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.010 INCH (0.254mm)
10
0.400*
(10.160)
MAX
0.125
(3.175) 0.020
MIN
(0.508)
MIN
0.018 ± 0.003
(0.457 ± 0.076)
N8 1098
LT1672/LT1673/LT1674
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PACKAGE DESCRIPTIO
Dimensions in inches (millimeters) unless otherwise noted.
S8 Package
8-Lead Plastic Small Outline (Narrow 0.150)
(LTC DWG # 05-08-1610)
0.189 – 0.197*
(4.801 – 5.004)
7
8
5
6
0.150 – 0.157**
(3.810 – 3.988)
0.228 – 0.244
(5.791 – 6.197)
1
0.010 – 0.020
× 45°
(0.254 – 0.508)
0.008 – 0.010
(0.203 – 0.254)
3
2
4
0.053 – 0.069
(1.346 – 1.752)
0.004 – 0.010
(0.101 – 0.254)
0°– 8° TYP
0.016 – 0.050
(0.406 – 1.270)
0.050
(1.270)
BSC
0.014 – 0.019
(0.355 – 0.483)
TYP
*DIMENSION DOES NOT INCLUDE MOLD FLASH. MOLD FLASH
SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE
**DIMENSION DOES NOT INCLUDE INTERLEAD FLASH. INTERLEAD
FLASH SHALL NOT EXCEED 0.010" (0.254mm) PER SIDE
SO8 1298
S Package
14-Lead Plastic Small Outline (Narrow 0.150)
(LTC DWG # 05-08-1610)
0.337 – 0.344*
(8.560 – 8.738)
14
13
12
11
10
9
8
0.228 – 0.244
(5.791 – 6.197)
0.150 – 0.157**
(3.810 – 3.988)
1
0.010 – 0.020
× 45°
(0.254 – 0.508)
0.008 – 0.010
(0.203 – 0.254)
2
3
4
5
6
0.053 – 0.069
(1.346 – 1.752)
0.004 – 0.010
(0.101 – 0.254)
0° – 8° TYP
0.016 – 0.050
(0.406 – 1.270)
0.014 – 0.019
(0.355 – 0.483)
TYP
7
0.050
(1.270)
BSC
*DIMENSION DOES NOT INCLUDE MOLD FLASH. MOLD FLASH
SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE
**DIMENSION DOES NOT INCLUDE INTERLEAD FLASH. INTERLEAD
FLASH SHALL NOT EXCEED 0.010" (0.254mm) PER SIDE
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.
S14 1298
11
LT1672/LT1673/LT1674
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TYPICAL APPLICATIO
Micropower Photodiode Amplifier
C1
20pF
R1
10M
GAIN: AZ = 10MΩ =
10% TO 90% RISE TIME: tr = 260µs
BANDWIDTH: BW = 1.7kHz
VS+
IPHOTODIODE
VOUT
IPHOTODIODE
–
880nm IR
PHOTODIODE
λ
OPTO-DIODE CORP
ODD-45W
LT1672
CD
170pF
VOUT
+
VS–
VS = ±1.2V TO ±15V
C1, CD SATISFY GAIN OF 5
STABILITY REQUIREMENT AT AC.
1672/3/4 TA05
RELATED PARTS
PART NUMBER
DESCRIPTION
COMMENTS
LTC®1440/41/42
Micropower Single/Dual Comparators with 1% Reference
LTC1440: Single, LTC1441/42: Dual
LTC1443/LTC1444/LTC1445
Micropower Quad Comparators with 1% Reference
LTC1443: 1.182 Reference
LTC1444/45: 1.221V Reference and Adjustable Hysteresis
LT1466/LT1467
75µA Dual/Quad Rail-to-Rail Input and Output Op Amps
390µV VOS(MAX), Gain Bandwidth = 120kHz
LT1490A/LT1491A
50µA Dual/Quad Rail-to-Rail Input and Output Op Amps
950µV VOS(MAX), Gain Bandwidth = 200kHz
LT1494/LT1495/LT1496
1.5µA Max Single/Dual/Quad Over-the-Top
Precision Rail-to-Rail Input and Output Op Amps
Unity Gain Stable Version of the LT1672/LT1673/LT1674
LTC1540
Nanopower Single Comparator with 1% Reference
350nA Supply Current
LT1636
Single Over-the-Top Micropower, Rail-to-Rail
Input and Output Op Amp
225µV VOS(MAX), IS = 55µA (Max), Gain Bandwidth = 200kHz,
Shutdown Pin, MSOP
LT2078/LT2079
55µA Dual/Quad Single Supply Op Amps
120µV VOS(MAX), Gain Bandwidth = 200kHz
LT2178/LT2179
17µA Dual/Quad Single Supply Op Amps
120µV VOS(MAX), Gain Bandwidth = 60kHz
LT1782
Micropower, Over-The-Top, SOT-23, Rail-to-Rail
Input and Output Op Amp
SOT-23, 800µV VOS(MAX) , IS = 55µA (Max),
Gain-Bandwidth = 200kHz, Shutdown Pin
LT1783
1.2MHz, Over-The-Top, Micropower, Rail-to-Rail
Input and Output Op Amp in SOT-23
SOT-23, 800µV VOS(MAX) , IS = 300µA (Max),
Gain-Bandwidth = 1.2MHz, Shutdown Pin
12
Linear Technology Corporation
167234f LT/TP 0101 4K • PRINTED IN USA
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408)432-1900 ● FAX: (408) 434-0507 ● www.linear-tech.com
 LINEAR TECHNOLOGY CORPORATION 2001