ak5354 AKM Semiconductor, Inc., ak5354 Datasheet - Page 17

• Manufacturer Part Number: ak5354
• Description: Low Power 20bit ?? Adc With Pga
• Manufacturer: AKM Semiconductor, Inc.

ASAHI KASEI
[AK5354]
1. Grounding and Power Supply Decoupling
The AK5354 requires careful attention to power supply and grounding arrangements. VA is usually supplied from analog
supply in system. VD is a power supply pin to interface with the external ICs and is supplied from digital supply in
system. VSS of the AK5354 should be connected to analog ground plane. System analog ground and digital ground
should be connected together near to where the supplies are brought onto the printed circuit board. Decoupling capacitors
should be as near to the AK5354 as possible, with the small value ceramic capacitor being the nearest.
2. Voltage Reference
The input to VA Voltage sets the analog input range. A 0.1µF ceramic capacitor and a 10µF electrolytic capacitor is
connected to VA and VSS pins, normally. VCOM is a signal ground of this chip. An electrolytic 2.2µF in parallel with a
0.1µF ceramic capacitor attached to these pins eliminates the effects of high frequency noise. No load current may be
drawn from VCOM pin. All signals, especially clock, should be kept away from the VA, VD and VCOM pins in order to
avoid unwanted coupling into the AK5354.
3. Analog Inputs
The analog inputs are single-ended and the input resistance 9kΩ (typ). The input signal range scales with nominally 0.6 x
VA Vpp (typ) centered in the internal common voltage (typ. 0.45 x VA). Usually, the input signal cuts DC with a
capacitor. The cut-off frequency is fc=(1/2πRC). The AK5354 can accept input voltages from VSS to VA. The ADC
output data format is 2’s complement. The DC offset including ADC own DC offset removed by the internal HPF
(fc=3.4Hz@fs=44.1kHz).
MS0054-E-02
2004/12
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