SGMICRO FT2928P

The ft2928 is a fully integrated, highly efficient, 2x6.8W filterless Class-G stereo audio power amplifier with automatic level control (ALC) and battery tracking AGC. It integrates dual filterless Class-D audio amplifiers with an adaptive Class-G synchronous boost regulator and operates with a wide range of supply voltages from 2.7V to 5.5V. With a supply voltage at 3.6V, the ft2928 can deliver an output power of 6.8W per channel with 10% THD+N, or 5.5W per channel with 1% THD+N, into a pair of 4Ω speaker loads. In ft2928, the power supply rails of the audio amplifiers’ output stages are internally boosted and regulated by a synchronous PWM switching regulator with two integrated power switches. The boost regulator employs current-mode PWM control with proprietary multi-level Class-G topology to regulate the boosted output voltage dynamically in response to the voltage level of the audio outputs. The higher output power and greater power efficiency resulted from the adaptive Class-G boost regulator make ft2928 an ideal audio solution for battery-powered electronic devices. To facilitate various applications, the boost regulator in ft2928 is independently controlled with three operating modes: Adaptive Boost, Continual Boost, and Bypass. The ft2928 features ALC function to constantly monitor and safeguard the audio outputs against the boosted supply voltage, preventing output clipping distortion, excessive power dissipation, and speaker over-load. Once an over-level condition is detected in either channel, the ALC lowers the voltage gain of both audio amplifiers together to limit the peak audio outputs.

• Maximum output power in Non-ALC Mode (VDD = 3.6V, THD+N = 10%, Dual channels driven) 2x6.8W into a pair of 4Ω speaker loads (VDD = 3.6V, THD+N = 1%, Dual channels driven) 2x5.5W into a pair of 4Ω speaker loads
• ALC output power in ALC Mode (VDD = 3.6V, THD+N ≤ 0.6%, Dual channels driven) 2x5W into a pair of 4Ω speaker loads
• Wide range of supply voltages from 2.7V to 5.5V
• Dual filterless Class-D audio amplifiers integrated with an adaptive Class-G boost regulator
• Automatic level control to eliminate output clipping
• Battery tracking AGC to prevent battery voltage collapse
• Optional soft-drive for low-EMI operation
• Independent control of boost regulator
• Mute control for fast turn-off / turn-on of audio outputs
• Low THD+N: 0.02% (VDD = 3.6V, 4Ω + 33μH, Po = 2W/Ch, Dual channels driven)
• Wide ALC dynamic range: 11dB
• Maximum voltage gain: 26dB
• High efficiency: 80% (VDD = 3.6V, 4Ω + 33μH, PO = 2W/Ch, Dual channels driven) Comprehensive protection modes: Under-voltage lockout protection, Auto-recovering over-current protection, and Thermal over-load protection
• Available in TSSOP-28L package

• Blue Tooth Speakers
• Portable Audio Decks
• Consumer Audio Electronics