wm9090 Wolfson Microelectronics plc, wm9090 Datasheet - Page 13

• Manufacturer Part Number: wm9090
• Description: Ultra Low Power Audio Subsystem
• Manufacturer: Wolfson Microelectronics plc

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Pre-Production
DEVICE DESCRIPTION
INTRODUCTION
The WM9090 is an ultra-low power, high quality audio subsystem, including a headphone and
speaker driver. Its flexible architecture is designed to interface with a wide range of analogue
components. The small 2.0 x 2.5mm footprint makes it ideal for portable applications such as mobile
handsets.
Four flexible analogue input pins allow interfacing to up to four single-ended sources (eg. two stereo
signal pairs). A differential input can also be accommodated if required. Connection to an external
voice CODEC, FM radio, melody IC or generic line input are all fully supported. Signal routing to the
output mixers provides maximum flexibility to support a wide variety of usage modes.
Three analogue output drivers are integrated, including a high quality Class D speaker driver
supporting 750mW output power at 3.7V. A configurable automatic gain control (AGC) is provided on
the speaker output path, to prevent clipping or power overload at the loudspeaker.
Ground-referenced stereo headphone outputs are also provided; these are powered from an
integrated Charge Pump, enabling high quality, power efficient headphone playback. The ground-
referenced design reduces power consumption, improves bass response, and enables direct
headphone connection without any DC blocking capacitors. A DC Servo circuit is provided for DC
offset measurement and correction, thereby suppressing pops and reducing power consumption.
Internal differential signal routing and amplifier configurations have been optimised to provide the
lowest possible power consumption for a wide range of usage scenarios, including voice calls and
music playback. The speaker drivers offer low leakage and high PSRR; this enables direct
connection to a Lithium battery. The speaker driver provides eight levels of boost gain to allow output
signal levels to be maximised for many commonly-used SPKVDD/AVDD combinations.
An integrated oscillator is provided to support all the WM9090 clocking requirements, including the
Class D switching clock, Headphone Charge Pump and DC Servo control.
The WM9090 is controlled via a standard 2-wire I2C interface, providing full software control of all
features, together with device register readback. The interface provides support for I/O voltages up to
2.7V. An integrated Control Write Sequencer enables automatic scheduling of control sequences;
commonly-used signal configurations may be selected using ready-programmed sequences,
including time-optimised control of the WM9090 pop suppression features. Unused circuitry can be
disabled under software control, in order to save power; low leakage currents enable extended
standby/off time in portable battery-powered applications.
PP, January 2010, Rev 3.0
WM9090
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