Datasheet

TAS5414A, TAS5424A
www.ti.com SLOS535C –MAY 2009– REVISED APRIL 2011
EMI Considerations
Automotive level EMI performance depends on both careful integrated circuit design and good system level
design. Controlling sources of electromagnetic interference (EMI) was a major consideration in all aspects of the
TAS5414A and TAS5424A design.
The TAS5414A and TAS5424A have minimal parasitic inductances due to the short leads on the PSOP3
package. This dramatically reduces the EMI that results from current passing from the die to the system PCB.
Each channel of the TAS5414A and TAS5424A also operates at a different phase. The phase between channels
is I
2
C selectable to either 45° or 180°, to reduce EMI caused by high-current switching. The TAS5414A and
TAS5424A incorporate patent-pending circuitry that optimizes output transitions that cause EMI.
AM Radio EMI Reduction
To reduce interference in the AM radio band, the TAS5414A and TAS5424A have the ability to change the
switching frequency via I
2
C commands. The recommended frequencies are listed in Table 21. The fundamental
frequency and its second harmonic straddle the AM radio band listed. This eliminates the tones that can be
present due to the switching frequency being demodulated by the AM radio. To function properly, AM avoidance
requires the use of a 20-kΩ, 1% tolerance Rext resistor.
Table 21. Recommended Switching Frequencies for AM Mode Operation
US EUROPEAN
SWITCHING SWITCHING
AM FREQUENCY AM FREQUENCY
FREQUENCY FREQUENCY
(kHz) (kHz)
(kHz) (kHz)
522-540 417
540–917 500 540–914 500
917–1125 417 914–1122 417
1125–1375 500 1122–1373 500
1375–1547 417 1373–1548 417
1547–1700 357 1548–1701 357
Operating States
The operating regions, or states, of the TAS5414A and TAS5424A are depicted in the following tables.
Table 22. Operating States and Supplies
STATE NAME OUTPUT FETS CHARGE PUMP OSCILLATOR I
2
C AVDD and DVDD
STANDBY Hi-Z, floating Stopped Stopped Stopped OFF
Hi-Z Hi-Z, weak pulldown Active Active Active ON
Mute Switching at 50% Active Active Active ON
Normal operation Switching with audio Active Active Active ON
Table 23. Global Faults and Actions
LATCHED/
FAULT/ FAULT/EVENT MONITORING REPORTING ACTION ACTION
SELF-
EVENT CATEGORY MODES METHOD TYPE RESULT
CLEARING
POR Voltage fault All FAULT pin Hard mute (no ramp) Standby Self-clearing
UV Hi-Z, mute, normal I
2
C + FAULT pin Hi-Z Latched
CP UV Hi-Z
OV Hi-Z
Load dump All FAULT pin Standby Self-clearing
OTW Thermal warning Hi-Z, mute, normal I
2
C + CLIP_OTW pin None None Self-clearing
OTSD Thermal fault Hi-Z, mute, normal I
2
C + FAULT pin Hard mute Standby Latched
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