1. General description
The TDF8546 is one of a new generation of complementary quad Bridge-Tied Load (BTL)
audio power amplifiers intended for automotive applications. It has a best efficiency mode
with full I
2
C-bus controlled diagnostics, including start-up diagnostics. The TDF8546 can
operate at a battery voltage as low as 6 V making this amplifier suitable for stop/start-car
operation.
The new best efficiency principle uses a patented switch technique which reduces
switching distortion. To reduce power dissipation, the new best efficiency principle uses
the audio information on all four channels instead of only the front or rear signals.
Dissipation is more than 65 % less than standard BTL when used for front and rear
correlated audio signals. Dissipation is 35 % less than standard BTL when used for
uncorrelated (delayed) audio signals between front and rear. It is 17 % less for
uncorrelated audio signals when the front or rear information is used.
The amplifier uses a complementary DMOS output stage in a Silicon-On-Insulator (SOI)
based BCD process. The DMOS output stage ensures a high-power output signal with
perfect sound quality. The SOI-based BCD process ensures a robust amplifier, where
latch-up cannot occur, with good separation between the four independent channels, with
every component isolated and without substrate currents.
2. Features and benefits
Stop/start-car prepared: keeps operating without audible disturbance during engine
start at a battery voltage as low as 6 V
New best efficiency mode with patented low switching distortion
Extreme best efficiency mode (uses information from 4 channels) with 17 % less
dissipation for uncorrelated signals compared to 2-channel best efficiency mode.
Operates in either legacy (non-I
2
C-bus) or I
2
C-bus modes (3.3 V and 5 V compliant)
Four hardware-programmable I
2
C-bus addresses
Can drive 2 and 4 loads
Speaker fault detection
Start-up diagnostics with load detection: open, short, present; filtered for door-slam
and chatter relays
AC load (tweeter) detection with low and high current mode
Gain select after start-up without audible disturbance
Independent selectable soft mute of front and rear channels
Programmable gain (26 dB and 16 dB), independently programmable for the front and
rear channels
TDF8546
I
2
C-bus controlled 4 45 W best efficiency amplifier
Rev. 8 — 27 September 2013 Product short data sheet
