Philips Semiconductors
IEC 958 audio DAC
Preliminary specification
UDA1350ATS
1 FEATURES
1.1 General
• 2.7 to 3.6 V power supply
• Integrated digital filter and Digital-to-Analog Converter
(DAC)
• 256fs system clock output
• 20-bit data path in interpolator
• High performance
• No analog post filtering required for DAC.
1.2 Control
• Controlled either by means of static pins or via the
L3 microcontroller interface.
1.3 IEC 958 input
• On-chip amplifier for converting IEC 958 input to CMOS
levels
• Lock indication signal available on pin LOCK
• Lock indication signal combined on-chip with the Pulse
Code Modulation (PCM) status bit; in case non-PCM
has been detected pin LOCK indicates out-of-lock
• Key channel-status bits available via L3 interface (lock,
pre-emphasis, audio sample frequency, two channel
PCM indication and clock accuracy).
1.4 Digital sound processing and DAC
• Automatic de-emphasis when using IEC 958 input with
32.0, 44.1 and 48.0 kHz audio sample frequencies
• Soft mute by means of a cosine roll-off circuit selectable
via pin MUTE or the L3 interface
• dB linear volume control with 1 dB steps from 0 dB to
−60 dB and −∞ dB
• Bass boost and treble control in L3 control mode
• Interpolating filter (fs to 128fs) by means of a cascade of
a recursive filter and a FIR filter
• Third order noise shaper operating at 128fs generates
the bitstream for the DAC
• Filter stream digital-to-analog converter.
2 APPLICATIONS
• Digital audio systems.
3 GENERAL DESCRIPTION
Available in two versions:
• UDA1350ATS:
– only IEC 958 input to DAC in SSOP28 package.
• UDA1350AH:
– full featured version in QFP44 package.
The UDA1350ATS is a single chip IEC 958 audio decoder
with an integrated stereo digital-to-analog converter
employing bitstream conversion techniques.
A lock indication signal is available on pin LOCK indicating
that the IEC 958 decoder is locked. This pin is also used to
indicate whether PCM data is applied to the input or not.
In the event non-PCM data has been detected, the device
indicates out-of-lock.
By default the DAC output and the data output interface
are muted when the decoder is out-of-lock. However, this
setting can be overruled in the L3 control mode.
2000 Mar 29
3