Texas Instruments TPA2035D1 Скачать руководство пользователя страница 15

WHEN TO USE AN OUTPUT FILTER

1 nF

Ferrite

Chip Bead

V

O−

V

O

+

Ferrite

Chip Bead

1 nF

TPA2035D1

www.ti.com

................................................................................................................................................................................................

SLOS562 – AUGUST 2008

Design the TPA2035D1 without an output filter if the traces from the amplifier to the speaker are short. Wireless
handsets and PDAs are great applications for this class-D amplifier to be used without an output filter.

The TPA2035D1 passed FCC- and CE-radiated emissions testing with no shielding with speaker trace wires 100
mm long or less. For longer speaker trace wires, a ferrite bead can often be used in the design if failing radiated
emissions testing without an LC filter; and, the frequency-sensitive circuit is greater than 1 MHz. If choosing a
ferrite bead, choose one with high impedance at high frequencies, but very low impedance at low frequencies.
The selection must also take into account the currents flowing through the ferrite bead. Ferrites can begin to
loose effectiveness at much lower than rated current values. See the EVM User's Guide (

SLOU237

) for

components used successfully by TI.

Figure 34

shows a typical ferrite-bead output filter.

Figure 34. Typical Ferrite Chip Bead Filter

Copyright © 2008, Texas Instruments Incorporated

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TPA2035D1

Содержание TPA2035D1

Страница 1: ...ellent PSRR and CMRR Features like 75dB PSRR and improved Optimized PWM Output Stage Eliminates RF rectification immunity with a small PCB footprint WCSP amplifier plus single decoupling cap make LC O...

Страница 2: ...charge Tolerance Human Body Model HBM for all pins 2 2KV 1 Stresses beyond those listed under absolute maximum ratings may cause permanent damage to the device These are stress ratings only and functi...

Страница 3: ...VDD 2 5 V to 5 5 V 5 5 6 6 5 dB Resistance of internal pulldown RPD resistor from shutdown pin to 300 k GND TA 25 C RL 8 unless otherwise noted PARAMETER TEST CONDITIONS MIN TYP MAX UNIT VDD 5 V 2 75...

Страница 4: ...ntial as PGND using a direct connection GND A2 I to a single point ground High current Analog ground terminal Must be connected to same potential as GND using a direct PGND B3 connection to a single p...

Страница 5: ...3 24 25 KSVR Supply voltage rejection ratio vs Frequency 26 27 vs Time 28 GSM power supply rejection vs Frequency 29 KSVR Supply voltage rejection ratio vs Common mode input voltage 30 31 32 vs Freque...

Страница 6: ...DD P Output Power W O I Supply Current mA DD R 8 33 H L W 0 0 25 0 5 0 75 1 1 25 1 5 1 75 3 6 3 2 2 8 2 4 2 1 6 1 2 0 4 0 0 0 1 0 2 0 3 0 4 0 5 0 6 0 7 0 8 V 2 5 V DD V 5 V DD V 3 6 V DD I Supply Cur...

Страница 7: ...DD W P 50 mW O P 250 mW O 1 0 01 0 1 f Frequency Hz 20k 20 100 1k 10k V 2 5 V DD V 5 V DD V 4 V DD V 3 6 V DD V 3 V DD THD N Total Harmonic Distortion Noise R 4 L W 1 0 005 0 01 0 1 f Frequency Hz 20...

Страница 8: ...1 1 5 2 2 5 3 3 5 4 4 5 5 DC Common Mode Voltage V Supply Ripple Rejection Ratio dB V 2 5 V DD V 3 6 V DD V 5 V DD 90 80 70 60 50 40 30 20 10 0 0 0 5 1 1 5 2 2 5 3 3 5 4 4 5 5 DC Common Mode Voltage V...

Страница 9: ...5 60 10 100 1 k 10 k 100 k f Frequency Hz CMRR Common Mode Rejection Ratio dB V 3 6 V V 1 Vpp R 8 DD IC L W TPA2035D1 www ti com SLOS562 AUGUST 2008 COMMON MODE REJECTION COMMON MODE REJECTION RATIO R...

Страница 10: ...1 goes to shutdown mode and tries to reactivate itself after 20 s This auto recovery will continue until the short circuit event stops This feature can protect the device without affecting the device...

Страница 11: ...en into consideration when setting the corner frequency using input capacitors Equation 2 is reconfigured to solve for the input coupling capacitance If the corner frequency is within the audio band t...

Страница 12: ...nput In making the pad size for the WCSP balls it is recommended that the layout use nonsolder mask defined NSMD land With this method the solder mask opening is made larger than the desired land area...

Страница 13: ...with electro polishing Use of chemically etched stencils results in inferior solder paste volume control 7 Trace routing away from WCSP device should be balanced in X and Y directions to avoid uninte...

Страница 14: ...Output Power figures the maximum ambient temperature can be calculated with the following equation Note that the units on these figures are Watts RMS Because of crest factor ratio of peak power to RM...

Страница 15: ...ften be used in the design if failing radiated emissions testing without an LC filter and the frequency sensitive circuit is greater than 1 MHz If choosing a ferrite bead choose one with high impedanc...

Страница 16: ...xempt This component has a RoHS exemption for either 1 lead based flip chip solder bumps used between the die and package or 2 lead based die adhesive used between the die and leadframe The component...

Страница 17: ...D Max E Max 1 51 mm Min 1 51 mm Min 1 45 mm 1 45 mm...

Страница 18: ...sponsible for compliance with all legal regulatory and safety related requirements concerning its products and any use of TI components in its applications notwithstanding any applications related inf...

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