THS7001, THS7002

70-MHz PROGRAMMABLE-GAIN AMPLIFIERS

SLOS214B – OCTOBER 1998 – REVISED AUGUST 1999

22

POST OFFICE BOX 655303

APPLICATION INFORMATION

output clamping (continued)

–4

–3

–2

–1

0

1

2

3

4

–4

–3

–2

–1

012345

OUTPUT VOLTAGE

vs

CLAMP VOLTAGE (VL)

Clamp Voltage – V

RL=5.1 k Ω

VCC=±5 V & ±15 V

VI=5 V

Gain=+2 dB

RL=500 Ω

–4

–3

–2

–1

0

1

2

3

4

–5

–4

–3

–2

–1

01234

OUTPUT VOLTAGE

vs

CLAMP VOLTAGE (VH)

Clamp Voltage – V

RL=5.1 k Ω

VCC=±5 V & ±15 V

VI=–5 V

Gain=+2 dB

RL=500 Ω

Figure 58. Output Voltage vs Clamp Voltage

The accuracy of this clamp is dependant on the amount of current flowing through the internal clamping diodes.

As is typical with all diodes, the voltage drop across this diode increases with current. Therefore, the accuracy

of the clamp is highly dependant upon the output voltage, the clamping voltage difference, and the output

current. The accuracy of the clamps with different load resistances are shown in Figure 59.

–200

–160

–120

–80

–40

0

40

–5

–4

–3

–2

–1

0

VL=–4 V

NEGATIVE CLAMP ACCURACY (VL)

Expected Output Voltage– V

RL=500 Ω

Gain = +2dB

VL=–1 V

VL=–2 V

VL=–3 V

–160

–120

–80

–40

0

40

80

–5

–4

–3

–2

–1

0

VL=–4 V

RL=1 k Ω

Gain = +2dB

VL=–1 V

VL=–2 V

VL=–3 V

NEGATIVE CLAMP ACCURACY (VL)

Expected Output Voltage – V

–160

–120

–80

–40

0

40

80

–5

–4

–3

–2

–1

0

VL=–4 V

RL=5.1 k Ω

Gain = +2dB

VL=–1 V

VL=–2 V

VL=–3 V

NEGATIVE CLAMP ACCURACY (VL)

Expected Output Voltage – V

–80

–40

0

40

80

120

160

012345

VH=4 V

RL=500 Ω

Gain = +2dB

VH=1 V

VH=2 V

VH=3 V

POSITIVE CLAMP ACCURACY (VH)

Expected Output Voltage – V

–120

–80

–40

0

40

80

120

012345

VH=4 V

RL=1 k Ω

Gain = +2dB

VH=1 V

VH=2 V

VH=3 V

POSITIVE CLAMP ACCURACY (VH)

Expected Output Voltage – V

–120

–80

–40

0

40

80

120

012345

VH=4 V

RL=5.1 k Ω

Gain = +2dB

VH=1 V

VH=2 V

VH=3 V

POSITIVE CLAMP ACCURACY (VH)

Expected Output Voltage – V

Figure 59. Clamping Accuracy