7.1 Overview

The PCM1840 is a high-performance, low-power, quad-channel, audio analog-to-digital converter (ADC) with flexible audio interface control options. This device is intended for applications in voice-activated systems, AV receivers, TV and blu-ray players, professional microphones, audio conferencing, portable computing, communication, and entertainment applications. The high dynamic range of the device enables far-field audio recording with high fidelity. This device integrates a host of features that reduces cost, board space, and power consumption in space-constrained, battery-powered, consumer, home, and industrial applications. The device features are controlled through hardware by pulling pins high or low with resistors or a controller GPIO. The PCM1808 also supports a power-down and reset function by means of halting the system clock.

The PCM1840 consists of the following blocks and features:

• Quad-channel, multibit, high-performance delta-sigma (ΔΣ) ADC
• Differential audio inputs with a 2-V_RMS full-scale signal
• Low-noise, 1.6-µV_RMS, microphone bias output
• Hardware pin control operation to select the device features
• Audio bus serial interface master or slave select option
• Audio bus serial interface format select option
• Audio bus serial interface supported up to 192 kHz sampling
• Slave mode supports dynamic range enhancer (DRE) with 123-dB dynamic range
• Slave mode supports decimation filters with linear-phase or low-latency filter selection
• Master mode operation supported using system clock of 256 × f_S or 512 × f_S
• Power-down function by means of halting the audio clocks
• Integrated high-pass filter (HPF) that removes the dc component of the input signal
• Integrated low-jitter phase-locked loop (PLL) supporting a wide range of system clocks
• Integrated digital and analog voltage regulators to support single-supply 3.3-V operation