www.ti.com

PWM Section

TAS5086

SLES131 – FEBRUARY 2005

DETAILED DESCRIPTION (continued)

The TAS5086 has six channels of high performance digital PWM Modulators that are designed to drive switching

output stages (back-ends) in both single-ended (SE) and H-bridge (bridge tied load) configuration. The TAS5086

device uses noise-shaping and sophisticated error correction algorithms to achieve high power efficiency and

high-performance digital audio reproduction. The TAS5086 uses a 4

SNR performance from 20 Hz to 20 kHz.

The TAS5086 PWM interface is described by using the following notation:

PN + V

Where,

P = number of PWM signals per channel

N = number of channels

V = total number of valid signals used to reset the power stage

For example, the TAS5086 initial interface format means that there is 1 PWM signal per channel (N = 6) and 1

valid signal is used to reset the power stages.

The PWM section accepts 24-bit PCM data from the serial data interface and outputs six PWM audio output

channels to drive power 1N+1 compatible single-ended and BTL power stages.

The PWM interface supports:

•

TAS5186 in BTL or SE mode without any external glue logic, uses 1N+1 signaling.

•

TAS5142 in BTL or SE mode without any external glue logic, uses 1N+1 signaling.

•

TAS5111 SE without any external glue logic with a pulldown on the output, uses 1N+1 signaling.

•

TAS5111 BTL or TAS5112 BTL with one inverter per BTL channel of glue logic and a pulldown on the

output, uses 1N+1 signaling from TAS5086, 2N+1 input to TAS5111/12.

•

TAS5112 SE (with external glue logic)

See the application schematics for an example of the TAS5086 with the TAS5186 and the TAS5086 with

TAS5112 SE and TAS5111 SE.

The TAS5086 has input multiplexers that allow any of the input channels to be routed to any PWM channel and

output multiplexers to enable any PWM output to be routed to any PWM output pin.

It also has individual channel dc-blocking filters that are enabled by default.

Individual channel de-emphasis filters for 32, 44.1, and 48 kHz are included and can be enabled and disabled.

There is also a two channel down mix result that can be output on SDOUT (I2S format). This result can also be

sent to the left and right front channels (channels 1 and 2) and/or to the center and subwoofer (channels 5 and 6)

as well.

A mixer on the subwoofer channel supports bass management configuration 1.

PWM output characteristics

1. Up to 8x over sampling

2. 12x at Fs = 32 kHz, 8x at Fs = 48 kHz, 4x at Fs = 96 kHz, 2x at Fs = 192 kHz

3. 4th order noise shaping

4.

≥105-dB dynamic range 0–20 kHz (TAS5086 + TAS5186 system measured at speaker terminals)

5. THD < 0.06% (measured at TAS5086 outputs)

6. Adjustable maximum modulation limit of 93.8% to 99.2%

10