Datasheet

AD9122
Rev. B | Page 51 of 60
300
250
200
150
100
50
0
0 12001000800600400200
f
DAC
(MHz)
POWER (mW)
08281-047
Figure 79. DVDD18 Power Dissipation vs. f
DAC
Due to Inverse Sinc Filter
300
250
200
150
100
50
0
50 300250200150100
f
DATA
(MHz)
POWER (mW)
08281-048
1× INTERPOLATION
2×, 4×, 8× INTERPOLATION
Figure 80. DVDD18 Power Dissipation vs. f
DATA
Due to Fine NCO
TEMPERATURE SENSOR
The AD9122 has a band gap temperature sensor for monitoring
the temperature change of the AD9122. The temperature must
be calibrated against a known temperature to remove the part-
to-part variation on the band gap circuit used to sense the
temperature. The DACCLK must be running at a minimum
of 100 MHz to obtain a reliable temperature measurement.
To monitor temperature change, the user must take a reading
at a known ambient temperature for a single-point calibration
of each AD9122 device.
Tx = T
REF
+ 7.7 × (Code_x − Code_ref)/1000 + 1
where:
Code_x is the readback code at the unknown temperature, Tx.
Code_ref is the readback code at the calibrated temperature, T
REF
.
To use the temperature sensor, it must be enabled by setting
Register 0x01, Bit 4, to 0. In addition, to obtain accurate read-
ings, the die temperature range control register (Register 0x48)
should be set to 0x02.