NSA20957

NSA20957 is a high-voltage, high-speed MOSFET driver with floating PWM input, designed for Class-D audio amplifier applications. It integrates high-side and low-side overcurrent protection (for both high-side and low-side power devices), shoot-through prevention dead-time logic, and three voltage domains (VDD~VSS / VCC~COM / VB~VS). The NSA20957 features bidirectional current sensing capability that detects overcurrent conditions during both positive and negative load current without any external shunt resistors. A built-in protection control module provides safe protection sequencing and a programmable reset timer for overcurrent conditions. The internal dead-time generation module enables precise gate switching control and optimal dead-time settings for improved audio performance, including lower THD and reduced audio noise. NSA20957 is a high-power Class-D audio amplifier driver IC with integrated overcurrent protection. Combined with an error amplifier, two external power MOSFETs, and passive components, the NSA20957 forms a complete Class-D audio power amplifier with high-side/low-side overcurrent protection, shoot-through protection, and undervoltage protection. Overcurrent detection is achieved by sensing the power MOSFET's RDS(on), eliminating the conventional direct current sensing approach, thereby simplifying the system architecture and reducing application complexity. The analog PWM input and protection logic are placed in a floating well, as is the high-side circuitry. The breakdown voltage between the floating well and the chip substrate ground (COM) exceeds 300V, supporting power amplifier applications up to ±150V with output power exceeding 500W.

Applications

• Home theater systems
• Stereo systems
• Mini component systems
• Active speaker systems
• General-purpose audio power amplifiers

Key features

• Floating PWM input with integrated OCP on both high-side and low-side, with auto-recovery
• External 5V reference voltage output; programmable low-side OCP threshold
• Programmable preset dead time for improved THD performance
• 15ns @ DT pin voltage > 0.57V
• 25ns @ 0.57V > DT pin voltage > 0.36V
• 35ns @ 0.36V > DT pin voltage > 0.23V
• 80ns @ 0.23V > DT pin voltage > 0V
• High transient noise immunity (CMTI): > 50V/ns
• Output swing up to ±150V, enabling output power exceeding 500W
• 3.3V/5V logic-compatible input
• Maximum operating frequency up to 800kHz
• Wide temperature range: -40°C ~ 125°C
• Switching parameters:
• 90ns/105ns typical propagation delay
• 500ns maximum OCP delay
• 250ns maximum enable control delay
• Output source/sink current capability up to 2A
• RoHS compliant
• SOP16 (S) package