MB86060 Datasheet, PDF (4/6 Pages) Fujitsu Component Limited. – 16-Bit Interpolating Digital to Analog Converter

June 2000 Version 1.2
FME/MS/SFDAC1/FL_1/4270
MB86060 16-Bit Interpolating Digital to Analog Converter
Other benefits include a reduced effect due to the sinx/x roll-off due to the DAC sample and hold output
stage, which for a conventional DAC represents -4dB at Nyquist, compared to only -0.22dB when operating
in the x4 interpolating mode. Also the digital interpolation filters sharp cutoff and effective stop-band
attentuation improves both in and out-of-band SFDR. This is illustrated below.
-4dB
x1
mode
-13dB
Sinx
x ^-18dB
0
100
F_DAT & F_DAC
Filter Pass Band = 0.43.F_DAT (-0.1dB)
X2 (slow)
mode
0
-0.9dB
100
F_DAT
Filter Pass Band = 0.37.F_DAT (-0.1dB)
X2 (fast)
mode
-0.9dB
200
300
Sinx
x
-13dB
200
300
F_DAC
Sinx
x
0
100
200
F_DAT
Filter Pass Band = 0.43.F_DAT (-0.1dB)
x4
mode
-0.22dB
300
Sinx
x
0
100
200
300
F_DAT
400
400
400
F_DAC
400
F_DAC
500 MHz
500 MHz
500 MHz
500 MHz
The MB86060 features four interpolation filter modes x1, x2(slow), x2(fast) and x4. Mode x1 is as per a
conventional DAC, and choosing between the remaining three modes would depend on the system
requirements. Mode x2(slow) may be advantageous to a system requiring the benefits of interpolation
filtering but saving some power by not running the DAC core at full rate. Mode x2(fast) gives access to the
wider band, slower roll-off interpolation filter allowing wider band signals to be generated compared to the
other modes, for example 74MHz (-0.1dB) for 200MSa/s data rate. Mode x4 for the complete interpolation
filter operation.
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Copyright © 2000 Fujitsu Microelectronics Europe GmbH