AD707

REV. B

–8–

OUTLINE DIMENSIONS

Dimensions shown in inches and (mm).

8-Pin Metal Can

(H-08A)

45

°

BSC

0.100

(2.54)

BSC

0.034 (0.86)

0.027 (0.69)

0.045 (1.14)

0.027 (0.69)

0.160 (4.06)

0.110 (2.79)

0.100

(2.54)

BSC

0.200

(5.08)

BSC

6

8

5

7

1

4

2

3

REFERENCE PLANE

BASE & SEATING PLANE

0.335 (8.51)

0.305 (7.75)

0.370 (9.40)

0.335 (8.51)

0.750 (19.05)

0.500 (12.70)

0.045 (1.14)

0.010 (0.25)

0.050

(1.27)

MAX

0.040 (1.02) MAX

0.019 (0.48)

0.016 (0.41)

0.021 (0.53)

0.016 (0.41)

0.185 (4.70)

0.165 (4.19)

0.250 (6.35)

MIN

8-Pin Cerdip

(Q-8)

0.320 (8.13)

0.290 (7.37)

0.015 (0.38)

0.008 (0.20)

15

°

0

°

0.005 (0.13) MIN

0.055 (1.4) MAX

1

PIN 1

4

5

8

0.310 (7.87)

0.220 (5.59)

0.405 (10.29) MAX

0.200

(5.08)

MAX

SEATING

PLANE

0.023 (0.58)

0.014 (0.36)

0.070 (1.78)

0.030 (0.76)

0.060 (1.52)

0.015 (0.38)

0.150

(3.81)

MIN

0.200 (5.08)

0.125 (3.18)

0.100

(2.54)

BSC

8-Pin Plastic DIP

(N-8)

8

14

5

0.430 (10.92)

0.348 (8.84)

0.280 (7.11)

0.240 (6.10)

PIN 1

SEATING

PLANE

0.022 (0.558)

0.014 (0.356)

0.060 (1.52)

0.015 (0.38)

0.210 (5.33)

MAX

0.130

(3.30)

MIN

0.070 (1.77)

0.045 (1.15)

0.100

(2.54)

BSC

0.160 (4.06)

0.115 (2.93)

0.325 (8.25)

0.300 (7.62)

0.015 (0.381)

0.008 (0.204)

0.195 (4.95)

0.115 (2.93)

8-Lead SOIC

(SO-8)

0.1968 (5.00)

0.1890 (4.80)

8

5

4

1

0.2440 (6.20)

0.2284 (5.80)

PIN 1

0.1574 (4.00)

0.1497 (3.80)

0.0688 (1.75)

0.0532 (1.35)

SEATING

PLANE

0.0098 (0.25)

0.0040 (0.10)

0.0192 (0.49)

0.0138 (0.35)

0.0500

(1.27)

BSC

0.0098 (0.25)

0.0075 (0.19)

0.0500 (1.27)

0.0160 (0.41)

8

°

0

°

0.0196 (0.50)

0.0099 (0.25)

x 45

°

PRECISION CURRENT TRANSMITTER

The AD707’s excellent dc performance, especially the low offset

voltage, low offset voltage drift and high CMRR, makes it

possible to make a high precision voltage-controlled current

transmitter using a variation of the Howland Current Source

circuit (Figure 26). This circuit provides a bidirectional load

current which is derived from a differential input voltage.

6

2

3

AD707

0.1µF

4

0.1µF

7

R4

100k

Ω

R3

100k

Ω

R2

100k

Ω

R1

100k

Ω

–––

( )

R2

R1

Figure 26. Precision Current Source/Sink

The performance and accuracy of this circuit will depend almost

entirely on the tolerance and selection of the resistors. The scale

the accuracy of the load current and should be chosen carefully

or trimmed.

Ω

= 2 (15

µV)/l Ω +2 (0.1 µV/°C)/l Ω

+ 1 nA (100 k)/l

Ω (1.5 nA @ 125°C)

= 30

µA + 0.2 µA/°C + 100 µA

(150

µA @ 125°C)

= 130

µA/10 mA = 1.3% @ 25°C

= 180

µA/10 mA = 1.8% @ 125°C

Low drift, high accuracy resistors are required to achieve high

precision.