AD22151

–4–

REV. 0

FIELD – Gauss

0.025

0.020

0

0.015

0.005

0.010

–600

–400

–200

0

200

400

600

Figure 5. Signal Drift Over Temperature (–40

°C to +150°C)

vs. Field (–200 ppm); +5 V Supply

TEMPERATURE – C

0.25

0.20

0

0.15

0.05

0.10

–40

10

60

110

160

–0.05

Figure 6. Gain Variation from +25

°C vs. Temperature

(–200 ppm) Field; R1 –15 k

Ω

FIELD – Gauss

0.045

0.040

0

0.035

0.025

0.030

–800

–400

–200

0

200

400

600

0.020

0.015

0.010

0.005

–600

800

Figure 7. Signal Drift Over Temperature (–40

°C to +150°C)

vs. Field (–2000 ppm); +5 V Supply

TEMPERATURE – C

2.0

1.8

1.0

1.6

1.2

1.4

–40

10

60

110

160

–0.2

0.8

0.6

0.4

0.2

0

Figure 8. Gain Variation (from +25

°C) vs. Temperature

(–2000 ppm Field; R1 = 12 k

Ω)

TEMPERATURE COMPENSATION

The AD22151 incorporates a “thermistor” transducer that

detects relative chip temperature within the package. This

function provides a compensation mechanism for the various

temperature dependencies of the Hall cell and magnet combina-

tions. The temperature information is accessible at Pins 1 and 2

(

≈ +2900 ppm /°C) and Pin 3 (≈ –2900 ppm/°C) as represented

by Figure 9. The compensation voltages are trimmed to con-

negative TC voltage via an internal resistor (see Functional

Block Diagram). An external resistor connected between Pin 3

and Pins 1 or 2 will produce a potential division of the two comple-

mentary TC voltages to provide optimal compensation. The

aforementioned Pin 3 internal resistor provides a secondary TC

designed to reduce second order Hall cell temperature sensitivity.

TEMPERATURE – C

1.0

0.8

0

0.6

0.2

0.4

150

112

74

–2

–40

–0.2

–0.4

–0.6

–0.8

–1.0

36

TC1, TC2 VOLTS

TC3 VOLTS

Figure 9. TC1, TC2 and TC3 with Respect to Reference vs.

Temperature

The voltages present at Pins 1, 2 and 3 are proportional to the

supply voltage. The presence of the Pin 2 internal resistor

distinguishes the effective compensation ranges of Pins 1 and 2

(see temperature configuration in Figures 1 and 2, and typical

resistor values in Figures 10 and 11).

Variation occurs in the operation of the gain temperature

compensation for two reasons. First, the die temperature within