AD7729ARU Analog Devices Inc, AD7729ARU Datasheet - Page 8

• Manufacturer Part Number: AD7729ARU
• Description: IC ADC 15BIT DUAL W/DAC 28-TSSOP
• Manufacturer: Analog Devices Inc
• Type: ADC, DACr

Specifications of AD7729ARU

• Rohs Status: RoHS non-compliant
• Resolution (bits): 15 b
• Sampling Rate (per Second): 270.8k
• Data Interface: Serial
• Voltage Supply Source: Analog and Digital
• Voltage - Supply: 3V
• Operating Temperature: -40°C ~ 105°C
• Mounting Type: Surface Mount
• Package / Case: 28-TSSOP

AD7729
TERMINOLOGY
Absolute Group Delay
Absolute group delay is the rate of change of phase versus fre-
quency, dø/df. It is expressed in microseconds.
Differential Nonlinearity
This is the difference between the measured and the ideal
1 LSB change between any two adjacent codes in the DAC or
ADC.
Dynamic Range
Dynamic Range is the ratio of the maximum output signal to the
smallest output signal the converter can produce (1 LSB), ex-
pressed logarithmically, in decibels (dB = 201og
an N-bit converter, the ratio is theoretically very nearly equal to
2
value is degraded by converter noise and inaccuracies in the
LSB weight.
Gain Error
This is a measure of the output error between an ideal DAC and
the actual device output with all 1s loaded after offset error has
been adjusted out. In the AD7729, gain error is specified for the
auxiliary section.
Gain Matching Between Channels
This is the gain matching between the IRx and QRx channel
and is expressed in dBs.
Group Delay Between Channels
This is the difference between the group delay of the I and Q
channels and is a measure of the phase matching characteristics
of the two.
Integral Nonlinearity
This is the maximum deviation from a straight line passing
through the endpoints of the auxiliary DAC transfer function.
N
(in dB, 20Nlog10(2) = 6.02N). However, this theoretical
10
(ratio)). For
–8–
Output Rate
This is the rate at which data words are made available
(270.833 kHz).
Offset Error
This is the amount of offset, wrt V
is expressed in mVs.
Output Signal Span
This is the output signal range for the auxiliary DAC section.
Sampling Rate
This is the rate at which the modulators on the receive channels
sample the analog input.
Settling Time
This is the digital filter settling time in the AD7729 receive
section. On initial power-up or after returning from the power-
down mode, it is necessary to wait this amount of time to get
useful data.
Signal Input Span
The input signal range for the I and Q channels is biased about
V
Signal to (Noise + Distortion) Ratio
This is the measured ratio of signal to (noise + distortion) at the
output of the receive channel. The signal is the rms amplitude of
the fundamental. Noise is the rms sum of all nonfundamental
signals up to half the sampling frequency (f
The ratio is dependent upon the number of quantization levels
in the digitization process; the more levels, the smaller the quan-
tization noise. The theoretical signal to (noise + distortion) ratio
for a sine wave is given by:
REF
.
Signal to (Noise + Distortion) = (6.02N + 1.76) dB
REF
in the auxiliary DAC and
S
/2), excluding dc.
REV. 0