Datasheet

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LT1672/LT1673/LT1674

APPLICATIO S

FEATURES

DESCRIPTIO

TYPICAL APPLICATION

2µA Max, A

≥ 5 Single, Dual

and Quad Over-The-Top Precision

Rail-to-Rail Input and Output Op Amps

■

Gain of 5 Stable

■

Low Supply Current: 2

A Max per Amplifier

■

Rail-to-Rail Input and Output

■

Low Offset Voltage: 375

V Max

■

Over-The-Top

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 A

VOL

: 100V/mV Minimum Driving 100kΩ Load

■

Output Sources and Sinks 500µA Load Current

■

Reverse Battery Protected to 18V

The LT

1672/LT1673/LT1674 are ultralow power

≤ 2µA) decompensated (A

≥ 5) op amps with preci-

sion 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 (A

VOL

) 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 4µV

P-P

remarkably low considering the low supply current. For

unity gain stable versions of these amplifiers, see the

LT1494/LT1495/LT1496.

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.

■

Battery- or Solar-Powered Systems

■

Portable Instrumentation

■

Remote Sensor Amplifier

■

Micropower Filter

■

Photodiode Amplifier

■

High Impedance Circuits

Single Supply, 60µW Precision Instrumentation Amplifier

TC V

Distribution

, LTC and LT are registered trademarks of Linear Technology Corporation.

100k*

0.0047µF

= 100

BANDWIDTH = 1kHz

CMRR = 65dB AT 120Hz

*500V TRANSIENT PROTECTION

TOTAL SUPPLY CURRENT = 12µA

–

100k

100k1M

OUT

LT1389-2.5

1672/3/4 TA01

LT1672

1000pF

110k

IN1

IN2

–

1/2 LT1673

TC V

(µV/°C)

–1.5

UNITS

0.9

1672/3/4 TA02

–0.9 –0.3 0.3 1.5

120 AMPLIFIERS

= ±2.5V

–40°C to 85°C

Over-The-Top is a trademark of Linear Technology Corporation.

Summary of content (12 pages)

PAGE 1
LT1672/LT1673/LT1674 2µA Max, AV ≥ 5 Single, Dual and Quad Over-The-Top Precision Rail-to-Rail Input and Output Op Amps U FEATURES ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ 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.
PAGE 2
LT1672/LT1673/LT1674 W W W AXI U U 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 .................
PAGE 3
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.
PAGE 4
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.
PAGE 5
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.
PAGE 6
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.
PAGE 7
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.
PAGE 8
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 U Small-Signal Response W U U 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.
PAGE 9
LT1672/LT1673/LT1674 U W U U 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.
PAGE 10
LT1672/LT1673/LT1674 U TYPICAL APPLICATIO S Battery Current Monitor IL CHARGE Over-the-Top Comparator with Hysteresis RSENSE 0.
PAGE 11
LT1672/LT1673/LT1674 U 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.
PAGE 12
LT1672/LT1673/LT1674 U 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.