STW5094 STMicroelectronics, STW5094 Datasheet - Page 7

• Manufacturer Part Number: STW5094
• Description: Audio DSPs 14-Bit Linear CODEC
• Manufacturer: STMicroelectronics

Specifications of STW5094

• Mounting Style: SMD/SMT
• Package / Case: TFBGA-36
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

STw5094
II.2 Power up down control:
It is recommended that all programmable functions (excluding the gain controls) are set while the device is
powered down. Power state control can then be included in the last programming instruction (the power up bit
PU is located in the last address register (CR18) so that the multi-byte mode of the control interface can be
easily used to program all the required functions before power up).
When a power up command is given, all the circuits needed for the selected mode are activated (in Voice mode
the DX output will remain in the high impedance state until the second FS pulse after power up arrives). A built-in
power consumption management function keeps in power down the blocks that are not needed by the selected
operating mode.
II.3 Power down state:
Following a period of activity, power down state may be reentered by writing 0 in bit PU in CR18. All the Control
2
Registers remain in their current state and can be changed by I
C control interface.
In addition to the power down instruction, the detection of absence of the current Master Clock (no transition
detected) automatically puts the device in power down state without setting bit PU. If transitions on the master
clock are detected the device is put again in power up.
II.4 Voice Transmit section:
This section is active in Voice Mode. Voice Transmit analog preamplifier gain is designed in two stages to
enable gains up to 42.5 dB. Stage 1 provides a selectable 0 or 20 dB gain via bit PG in CR4. Stage 2 is a
programmable gain amplifier which provides from 0 to 22.5 dB of additional gain in 1.5dB step. It can be
programmed with bits TXA in CR4. Two differential microphone inputs (MIC1P N, MIC2P N) and one single
ended line input (MIC3) are provided. The line input MIC3 can only be used with preamplifier gain set to 0dB in
both stages. The microphone input or Transmit Mute is selected with bits MS in CR4. In the Mute case, the
analog transmit signal is grounded. A separate MBIAS output can be used to bias a microphone (bit MB in CR4).
An active anti-alias filter then precedes the single bit
analog to digital converter that is followed by an 8th
order IIR digital TX channel filter. The TX channel filter is band-pass if the FS frequency is 8kHz and low-pass
if the FS frequency is 16kHz (bit VFS in CR0). A precision on chip voltage reference ensures accurate and highly
stable transmission levels. Any offset voltage arising in the analog blocks is cancelled by an internal autozero
circuit. Voice data is sent to the PCM I F to be serially sent to DX output.
II.5 Voice Receive section:
This section is active in Voice Mode. Voice Data coming from PCM I F DR pin is sent to the 8th order digital
IIR RX channel filter. The filter can be selected to be band-pass or low-pass, with bit HPB in CR5, when FS
frequency is 8kHz, while it is always low-pass when FS frequency is 16kHz. The filter is followed by a
digital
to analog converter and a 3rd order switched-capacitor reconstruction filter. The Sidetone can be summed to
the received signal (bit SI in CR5) and its amplitude can be programmed with bits SA in CR5.
II.6 Stereo Audio DAC section:
2
This section is active in Audio Mode. The Left and Right Audio samples coming from the I
S Interface are
interpolated with an FIR filter in order to feed the oversampled multi-bit
modulator, the digital to analog
converter is followed by a 3rd order switched-capacitor reconstruction filter.
II.7 Output Drivers section:
There are 3 Analog Output Drivers. The LSP N differential driver delivers 190mW typical power with 0.1%
T.H.D. (140mW minimum undistorted) on a 8 earpiece loudspeaker (piezoceramic loads up to 50nF can also
be driven, with a series resistor), it has a 30dB range gain control (bits LSA in CR7). The 2 single ended drivers
(HPL and HPR) deliver 20mW typical power with 0.1% T.H.D. (16.5mW minimum undistorted) on 30 stereo
headphones, they have a 40dB range gain control (CR8 for HPL and CR9 for HPR). It is possible to put all the
drivers in power-down, enable the LSP N one, enable the HPL one or enable HPL and HPR together
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