PKD01 datasheet(12/18 Pages) AD

12 / 18 page

REV. A

PKD01

–12–

APPLICATIONS INFORMATION

Optional Offset Voltage Adjustment

Offset voltage is the primary zero scale error component since a

variable voltage clamp limits voltage excursions at D1’s anode

and reduces charge injection. The PKD01 circuit gain and opera-

tional mode (positive or negative peak detection) determine the

applicable null circuit. Figures 5 through 8 are suggested circuits.

Each circuit also corrects amplifier C offset voltage error.

A. Nulling Gated Output gm Amplifier A. Diode D1 must

be conducting to close the feedback circuit during amplifier A

VOS adjustment. Resistor network RA – RC cause D1 to conduct

slightly. With DET = 0 and VIN = 0 V, monitor the PKD01

output. Adjust the null potentiometer until VOUT = 0 V. After

adjustment, disconnect RC from CH.

B. Nulling Gated gm Amplifier B. Set Amplifier B signal

input to VIN = 0 V and monitor the PKD01 output. Set DET =

1, RST = 1 and adjust the null potentiometer for VOUT = 0 V.

The circuit gain—inverting or noninverting—will determine which

null circuit illustrated in Figures 5 through 8 is applicable.

PKD01

1000pF

VOUT

VS–

VS+

0.1 F

DET

RST

–15V

200k

NOTES:

1. NULL RANGE =

( )

2. DISCONNECT RC FROM CH AFTER AMPLIFIER A ADJUSTMENT.

3. REPEAT NULL CIRCUIT FOR RESET BUFFER AMPLIFIER B IF REQUIRED.

RA, RB AND RC NOT NECESSARY FOR AMPLIFIER B ADJUSTMENT.

VIN+

100k

Figure 5. VOS Null Circuit for Unity Gain Positive Peak

Detector

PKD01

1000pF

VOUT

R2 = R3 + R4

VS–

VS+

25k

0.1 F

DET

RST

–15V

200k

NOTES:

1. NULL RANGE =

( )(

)

2. DISCONNECT RC FROM CH AFTER AMPLIFIER A ADJUSTMENT.

3. REPEAT NULL CIRCUIT FOR RESET BUFFER AMPLIFIER B IF REQUIRED.

VIN–

VIN+

20k

R1 + R3

Figure 6. VOS Null Circuit for Differential Peak Detector

PKD01

1000pF

VOUT

VIN

0.1 F

VS–

VS+

25k

DET

20k

RST

–15V

200k

NOTES:

1. NULL RANGE =

( )

2. DISCONNECT RC FROM CH AFTER AMPLIFIER A ADJUSTMENT.

3. REPEAT NULL CIRCUIT FOR RESET BUFFER AMPLIFIER B IF REQUIRED.

Figure 7. VOS Null Circuit for Negative Peak Detector

PKD01

1000pF

VOUT

VIN

20k

0.1 F

VS–

VS+

25k

DET

R4 = R2 R1

R1 + R2

RST

–15V

200k

GAIN = 1 +

R1 + R3

NOTES:

1. NULL RANGE =

( )

2. DISCONNECT RC FROM CH AFTER AMPLIFIER A ADJUSTMENT.

3. REPEAT NULL CIRCUIT FOR RESET BUFFER AMPLIFIER B IF REQUIRED.

Figure 8. VOS Null Circuit for Positive Peak Detector with

Gain

PKD01 Datasheet(PDF) 12 Page - Analog Devices

PKD01 Datasheet(HTML) 12 Page - Analog Devices

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18

Datasheet Download

Link URL