LT1673CS8 View Datasheet(PDF) - Linear Technology

Part Name

Description

Manufacturer

LT1673CS8

2µA Max, AV ≥ 5 Single, Dual and Quad Over-The-Top Precision Rail-to-Rail Input and Output Op Amps

Linear Technology 

LT1672/LT1673/LT1674

TYPICAL PERFORMANCE CHARACTERISTICS

Small-Signal Response

Small-Signal Response

Large-Signal Response

VS = ±15V

CL = 100pF

AV = 5

1672/3/4 G19

VS = 5V

CL = 100pF

AV = 5

1672/3/4 G20

VS = 5V

CL = 100pF

AV = 5

1672/3/4 G21

APPLICATIO S I FOR ATIO

Start-Up Characteristics

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.

5

4

OUTPUT HIGH

3

2

OUTPUT LOW

OUTPUT VS/2

1

0

0

1

2

3

4

5

TOTAL SUPPLY VOLTAGE (V)

1672/3/4 FO1

Figure 1. Start-Up Characteristics

V+

V+

V+

+

+

+

–

–

–

820k

V–

OUTPUT HIGH

V–

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

While the LT1672/LT1673/LT1674 will function normally

with its inputs taken above the positive supply, the com-

mon mode range does not extend beyond approximately

300mV below the negative supply at room temperature.

8

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