[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
AKM [ ASAHI KASEI MICROSYSTEMS ]
