AK4533 Datasheet, PDF (15/40 Pages) Asahi Kasei Microsystems – Audio Codec with Touch Screen Controller

[ASAHI KASEI]
Overview
The AK4533 consists of three blocks; Audio A/D Converter, Audio D/A Converter, and Touch Screen A/D Converter. These blocks
operate independently. The following describes the overview of the device.
(1) 1 channel 16 bit audio A/D converter:
„ 64fs oversampling ∆-Σ type
„ On-chip decimation LPF and digital HPF
„ Audio Format: 2's complement, MSB first, serial output
„ Fixed Gain Amplifier for microphone input: +20dB
„ Input Programmable Gain Amplifier (IPGA) with automatic gain control (AGC) function
-8dB to +20dB, 0.5dB/step
„ Input signal range of ADC scales with the supply voltage: 0.6 x VA (excluding fixed gain amplifier)
„ Power down control independent with DAC block and Touch panel block
(2) 2 channel 16 bit audio D/A converter:
„ 128fs/256fs oversampling ∆-Σ type
„ 8 times interpolation digital filter
„ 2nd order SCF: single-ended
„ Audio format: 2's complement, MSB first, serial input
„ Digital ATT: 0dB to -22.5dB, 1.5dB/step
„ Output signal range of DAC scales with the supply voltage: 0.6 x VA
„ Power down control independent with L channel and R channel
(3) 1ch 12bit A/D converter for Touch Screen and Battery Measurement
„ 12bit Resolution, Successive Approximation Resistor (SAR) type
„ Two pairs of touch screen driver: X-axis and Y-axis
- Measurement of X-axis position: TSY_TOP pin is automatically selected.
- Measurement of Y-axis position: TSX_TOP pin is automatically selected.
„ Power Down Mode
- A/D converter goes to power down state
- Touch Screen Driver is open state.
„ Waiting State for Pen Interrupt
- TSY_BTM is connected to VA, and TSY_TOP is open state
- TSX_TOP is open state, and TSX_BTM is connected to AGND through internal resistor. When the touch
screen is pressed, the device outputs INT signal.
„ Measurement of Battery Voltage
- 2ch BTI inputs
- Full scale of BTI input is TPVREFIN
(4) Control Registers
„ 4-wire I/F: 8bit/word, 8words
„ The registers are set to default value by RESETB pin ("L" level)
„ This interface is used for IPGA (AGC), PD control, mode selection of Touch Screen
(5) Pin Control
„ PDB pin
- When PDB pin is "L", all blocks in the device including VCOM buffer goes to power-down state.
- Internal registers are set to default value.
- ADC for Touch Screen is power-down state (Pen Interrupt function is disabled).
- All digital output pins is "L".
- When PDB pin goes to "H", power-down state is cleared, and the device is ready to normal operation.
- VCOM buffer start to operation after exiting power-down state.
- It takes time for VCOM to settle the appropriate voltage through external capacitor. (4ms@4.7uF)
„ RESETB pin
- All blocks in the device except for VCOM Buffer is power-down state when RESETB pin is "L".
- When RESETB pin is "L", internal registers are set to default value.
- ADC for Touch Screen is power-down state (Pen Interrupt function is disabled).
- All digital output pin is "L", and A/T I/F is NOT available when RESETB is "L".
<Revision 0.9a>
14
July 00