TLV320AIC1106 Datasheet, PDF (11/17 Pages) Texas Instruments – PCM CODEC

TLV320AIC1106
PRINCIPLES OF OPERATION
SLAS357 – DECEMBER 2001
power-up initialization
An external reset with a minimum pulse width of 500 ns must be applied to the active-low RESET terminal with
MCLK active to ensure reset upon power up.
Table 1. Power-Up and Power-Down Power Consumption
(V_DD = 2.7 V, Earphone Amplifier Loaded)
DEVICE STATUS
Power up
Power down
MAXIMUM POWER CONSUMPTION
16.2 mW
81 µW
The loss of MCLK (no transition detected) automatically enters the device into a power-down state with PCMO
in the high-impedance state. If an asynchronous power down occurs during a pulse code modulation (PCM)
data transmit cycle, the PCM interface remains powered up until the PCM data is completely transferred.
conversion laws
The device can be programmed either for a 13-bit linear or 8-bit (µ-law) companding mode. The companding
operation approximates the CCITT G.711 recommendation. The linear mode operation uses a 13-bit twos
complement format. Linear mode is selected with LINSEL low. LINSEL is high for companding.
transmit operation
microphone input
The microphone input stage is a low-noise differential amplifier. The microphone must be capacitively coupled
to the MICIN– and MICIN+ terminals. Preamplifier (MIC Amp 1) gain is determined by selection of external
resistors R2 and R3. To achieve the recommended gain setting of 23.5 dB for MIC Amp 1, resistor values of
R2 = 34 kΩ and R3 = 510 kΩ are suggested. A 1% tolerance is recommended for all resistors to meet the
specification. The recommended range for R2 is 34 – 100 kΩ. For values above 100 kΩ, the noise performance
of the channel is degraded.
+V
R3 _{MICGAIN–}
R1
C1 _R2
MICIN+
+
_
MIC Amp 1
C1 ^R2
MICIN–
R1
R3 ^MICGAIN+
R1 = 2 kΩ
C1 = 0.22 µF
ǒ Ǔ _{MIC Amp 1 Gain in dB + 20 log}
R3
R2
Figure 3. Typical Microphone Interface
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