描述 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 modewith full I2C-bus controlled diagnostics, including start-up diagnostics. The TDF8546 canoperate at a battery voltage as low as 6 V making this amplifier suitable for stop/start-caroperation.
The new best efficiency principle uses a patented switch technique which reducesswitching distortion. To reduce power dissipation, the new best efficiency principle usesthe 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 rearcorrelated audio signals. Dissipation is 35 % less than standard BTL when used foruncorrelated (delayed) audio signals between front and rear, and 17 % less foruncorrelated 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 withperfect sound quality. The SOI-based BCD process ensures a robust amplifier, wherelatch-up cannot occur, with good separation between the four independent channels, withevery component isolated and without substrate currents.

特性 Features

Stop/start-car prepared: keeps operating without audible disturbance during enginestart 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 % lessdissipation 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-slamand 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 andrear channels
Line driver mode supports engine start at a battery voltage as low as 6 V (16 dB andmid-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 loador 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 junctiontemperatures
Programmable low battery voltage detection to enable 7.5 V or 6 V minimum batteryvoltage operation
Overvoltage protection (load-dump safe up to VP = 50 V) with overvoltage pre-warningat 16 V
Offset detection