WM7130A WOLFSON [Wolfson Microelectronics plc], WM7130A Datasheet - Page 7

• Manufacturer Part Number: WM7130A
• Description: Bottom Port Analogue Silicon Microphone
• Manufacturer: WOLFSON [Wolfson Microelectronics plc]

Pre-Production
APPLICATIONS INFORMATION
RECOMMENDED EXTERNAL COMPONENTS
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Figure 1 WM7130A Recommended External Components
A DC-blocking output capacitor is required on the OUTPUT pin, as illustrated in Figure 1. A single
capacitor is required for a single-ended connection. The capacitor must be correctly selected as it
affects the cut-off frequency of the output path. A low cut-off frequency is desirable as it means there
is no significant filtering of the audio bandwidth.
The 3dB cut-off frequency of the output path is given by the equation below, where C is the output
capacitance and R is the input resistance of the other circuit.
A typical recommended configuration, with 1uF DC-blocking capacitor and 20kΩ minimum input
circuit impedance, gives a 3dB cut-off frequency of 10Hz or less. Tantalum electrolytic capacitors are
particularly suitable for the DC-blocking components as they offer high stability in a small package
size
PP, Rev 3.1, April 2012
WM7130A
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