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 I²C-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, and 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.
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## Features
* 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 I²C-bus) or I²C-bus modes (3.3 V and 5 V compliant)
* Four hardware-programmable I²C-bus addresses
* Can drive 2 Ω and 4 Ω 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
* Line driver mode supports engine start at a battery voltage as low as 6 V (16 dB and mid-tap voltage 0.25 VP)
* Programmable clip detect: 2 %, 5 % or 10 %
* Programmable thermal pre-warning
* Pin STB can be programmed/multiplexed with second-clip detect
* Clip information of each channel can be directed separately to pin DIAG or pin STB
* Independent enabling of thermal-, clip- or load fault information (short across the load or to VP or to ground) on pin DIAG
* Loss-of-ground and open VP safe (minimum series resistance required)
* All amplifier outputs short-circuit proof to ground, supply voltage and across the load (channel independent)
* All pins short-circuit proof to ground
* Temperature controlled gain reduction to prevent audio holes at high junction temperatures
* Programmable low battery voltage detection to enable 7.5 V or 6 V minimum battery voltage operation
* Overvoltage protection (load-dump safe up to VP = 50 V) with overvoltage pre-warning at 16 V
