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Features
Conventional pulse width modulation.
Externally controllable switching frequency.
50kHz to 200kHz switching frequency range.
Integrated error amp and feedback amp.
Turn−on soft start and under voltage lockout.
Over modulation protection (soft clipping).
Externally controllable output current limiting and thermal shutdown protection.
Self checking protection diagnostic.
Description The IC combination of the LM4651 driver and the LM4652 power MOSFET provides a high efficiency, Class D subwoofer amplifier
solution.
The LM4651 is a fully integrated conventional pulse width modulator driver IC. The IC contains short circuit, under voltage,
over modulation, and thermal shut down protection circuitry. The LM4651also contains a standby function which shuts down the
pulse width modulation minimizing supply current. The LM4652 is a fully integrated H-bridge power MOSFET IC in a TO-220 power
package. The LM4652 has a temperature sensor built in to alert the LM4651 when the die temperature of the LM4652 exceeds the
threshold. Together, these two IC's form a simple, compact high power audio amplifier solution complete with protection normally
seen only in Class AB amplifiers. Few external components and minimal traces between the IC's keep the PCB area small and
aids in EMI control.
The near rail-to-rail switching amplifier substantially increases the efficiency compared to Class AB amplifiers. This high
efficiency solution significantly reduces the heat sink size compared to a Class AB IC of the same power level. This two-chip
solution is optimum for powered subwoofers and self powered speakers.
Key Specification
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Output power into 4Ω with < 10% THD.
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170W (Typ)
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THD at 10W, 4Ω, 10 − 500Hz.
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< 0.3% THD (Typ)
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Maximum efficiency at 125W
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85% (Typ)
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Standby attenuation.
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>100dB (Min)
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Applications
Powered subwoofers for home theater and PC's
Car booster amplifier
Self-powered speakers
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