AD5316R datasheet(22/24 Pages) AD

22 / 24 page

AD5316R

Data Sheet

Rev. C | Page 22 of 24

INTERNAL REFERENCE SETUP

By default, the internal reference is on at power-up. To reduce

the supply current, the on-chip reference can be turned off.

Command 0111 is reserved for setting up the internal reference.

To turn off the internal reference, set the software programmable

bit, DB0, in the input shift register using Command 0111, as

shown in Table 16. Table 15 shows how the state of the DB0 bit

corresponds to the mode of operation.

Table 15. Internal Reference Setup Register

Internal Reference

Setup Register (Bit DB0)

Action

Reference on (default)

Reference off

SOLDER HEAT REFLOW

As with all IC reference voltage circuits, the reference value

experiences a shift induced by the soldering process. Analog

Devices, Inc., performs a reliability test called precondition to

mimic the effect of soldering a device to a board. The output

voltage specification in Table 2 includes the effect of this

reliability test.

Figure 46 shows the effect of solder heat reflow (SHR) as

measured through the reliability test (precondition).

2.498

2.499

2.500

2.501

2.502

VREF (V)

POSTSOLDER

HEAT REFLOW

PRESOLDER

HEAT REFLOW

Figure 46. SHR Reference Voltage Shift

LONG-TERM TEMPERATURE DRIFT

Figure 47 shows the change in the VREF (ppm) value after

1000 hours at 25°C ambient temperature.

ELAPSED TIME (Hours)

140

120

100

200

300

400

500

600

700

800

900

1000

–20

Figure 47. Reference Drift Through to 1000 Hours

THERMAL HYSTERESIS

Thermal hysteresis is the voltage difference induced on the

reference voltage by sweeping the temperature from ambient

to cold, then to hot, and then back to ambient.

Thermal hysteresis data is shown in Figure 48. It is measured by

sweeping the temperature from ambient to −40°C, then to +105°C,

and then back to ambient. The VREF delta is then measured between

the two ambient measurements (shown in blue in Figure 48). The

same temperature sweep and measurements were immediately

repeated, and the results are shown in red in Figure 48.

–50

–100

–150

–200

DISTORTION (ppm)

FIRST TEMPERATURE SWEEP

SUBSEQUENT TEMPERATURE SWEEPS

Figure 48. Thermal Hysteresis

Table 16. 24-Bit Input Shift Register Contents for Internal Reference Setup Command1

DB23 (MSB)

DB22

DB21

DB20

DB19 to DB16

DB15 to DB1

DB0 (LSB)

1 or 0

Command bits (C3 to C0)

Address bits (don’t care)

Don’t care

Reference setup register

X = don’t care.

AD5316R Datasheet(PDF) 22 Page - Analog Devices

AD5316R Datasheet(HTML) 22 Page - Analog Devices

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

Datasheet Download

Link URL