9

FN8087.1

May 5, 2005

Turn-On Time

The ISL60007 devices operate with ultra-low supply current

and thus the time to bias up internal circuitry to final values

will be longer than with references that require higher

current. Normal turn-on time is typically 4ms. This is shown

in Figure 30. Since devices can vary in supply current down

to 250nA, turn-on time can last up to about 6ms. Care

should be taken in system design to include this delay before

measurements or conversions are started.

Temperature Coefficient

The limits stated for temperature coefficient (tempco) are

governed by the method of measurement. The

overwhelming standard for specifying the temperature drift of

a reference is to measure the reference voltage at two

divide by the temperature extremes of measurement

ppm/°C. This is the “Box” method for specifying temperature

coefficient.

400

350

300

250

200

150

100

50

0

1

10

100

1000

10000

100000

FIGURE 28. NOISE REDUCTION

& 10µF + 2k

Ω

GND

ISL60007

0.01µF

10µF

2k

Ω

0.1µF

10µF

FIGURE 29.

0

0.5

1

1.5

2

2.5

3

3.5

0

2

4

6

8

10

12

TIME (ms)

400nA

570nA

250nA

FIGURE 30. TURN-ON TIME (+25°C)

Typical Application Circuits

FIGURE 31. PRECISION 2.5V, 50mA REFERENCE

2N2905

2.5V/50mA

0.001µF

GND

ISL60007

R = 200

Ω

ISL60007