ad73311 Analog Devices, Inc., ad73311 Datasheet - Page 25

• Manufacturer Part Number: ad73311
• Description: Low Cost, Low Power Cmos General Purpose Analog Front End
• Manufacturer: Analog Devices, Inc.

Analog Output
The AD73311’s differential analog output (VOUT) is produced
by an on-chip differential amplifier. The differential output
can be ac-coupled or dc-coupled directly to a load or to an
external amplifier. Figure 26 shows a simple circuit providing
a differential output with ac coupling. The capacitors in this
circuit (C
as follows:
Figures 24 and 25 detail dc- and ac-coupled input circuits for
single-ended operation respectively.
V
IN
V
IN
OUT
CIN
) are optional; if used, their value can be chosen
where f
100
0.047 F
R
L
0.047 F
100
C
C
C
0.1 F
C
= desired cutoff frequency.
0.1 F
OUT
OUT
OUT
REFOUT
REFOUT
10k
=
VOUTP
VOUTN
2π f
VINP
VINN
REFCAP
VINP
VINN
REFCAP
(VOUT CHANNEL)
1
C
R
L
AD73311
REFERENCE
AD73311
REFERENCE
VOLTAGE
AD73311
VOLTAGE
Figure 27 shows an example circuit for providing a single-ended
output with ac coupling. The capacitor of this circuit (C
not optional if dc current drain is to be avoided.
Digital Interfacing
The AD73311 is designed to easily interface to most common
DSPs. The SCLK, SDO, SDOFS, SDI and SDIFS must be
connected to the SCLK, DR, RFS, DT and TFS pins of the
DSP respectively. The SE pin may be controlled from a parallel
output pin or flag pin such as FL0–2 on the ADSP-21xx (or XF
on the TMS320C5x) or, where SPORT powerdown is not
required, it can be permanently strapped high using a suitable
pull-up resistor. The RESET pin may be connected to the sys-
tem hardware reset structure or it may also be controlled using a
dedicated control line. In the event of tying it to the global sys-
tem reset, it is necessary to operate the device in mixed mode,
which allows a software reset, otherwise there is no convenient
way of resetting the device. Figures 28 and 29 show typical
connections to an ADSP-2181 and TMS320C5x respectively.
TMS320C5x
ADSP-21xx
DSP
DSP
R
L
C
TFS
DT
SCLK
DR
RFS
FL0
FL1
FSX
DX
DR
FSR
CLKX
CLKR
XF
OUT
VOUTP
VOUTN
(VOUT CHANNEL)
RESETB
RESETB
SDOFS
SDOFS
SDIFS
SDIFS
SCLK
SCLK
SDO
SDO
SDI
SDI
SE
SE
AD73311
AD73311
AD73311
CODEC
AD73311
CODEC
OUT
) is