[AK2364]

MS1431-E-01

2012/10

- 4 -

4. Circuit Configuration

Block

Description

MIX

2nd-mixer to convert the input signal down to 450Hz.

AGC+BPF

The circuit composed of AGC and BPF, where the desired signal is amplified and

spurious components included in the signal from the 2nd-mixer are eliminated.

Divider

The circuit to divide the signal from LOIN pin and supply BPF with CLK.

LIMTER

The circuit to amplify the signal filtered at the AGC+BPF stage and generate rectangular

wave.

DISCRI

The demodulator circuit with PLL FM detector, where the audio signal is recovered.

LPF

The Low-pass filter to eliminate the noise generated at the DISCRI stage.

Noise AMP

The amplifier to compose the Band-pass filter for noise squelch.

Noise Rectifier

The rectification circuit to detect the noise level.

Comparator

The circuit to compare the noise level with reference voltage level.

RSSI

The circuit to indicate the Received Signal Strength Indicator(RSSI) by generate a DC

voltage corresponding to the input level from LIMITER.

VIREF

The circuit to generate internal reference voltage.

LDO

The circuit to supply 2.7V power for some circuits.

Control Logic

The control register controls the status of internal condition by serial data that consists of

1 instruction bit, 6 address bits and 8 data bits.

Note: When you use AK2364 in AVDD=2.6 to 3.6V operation, VREFA pin is connected to AVDD pin

for power supplying.