TPA321 350-mW Mono Class-AB Audio Amplifier with Differential Inputs |


350-mW Mono Class-AB Audio Amplifier with Differential Inputs



The TPA321 is a bridge-tied load (BTL) audio power amplifier developed especially for low-voltage applications where internal speakers are required. Operating with a 3.3-V supply, the TPA321 can deliver 250-mW of continuous power into a BTL 8- load at less than 1% THD+N throughout voice band frequencies. Although this device is characterized out to 20 kHz, its operation was optimized for narrower band applications such as cellular communications. The BTL configuration eliminates the need for external coupling capacitors on the output in most applications, which is particularly important for small battery-powered equipment. This device features a shutdown mode for power-sensitive applications with a quiescent current of 0.15 µA during shutdown. The TPA321 is available in an 8-pin SOIC surface-mount package and the surface-mount PowerPAD™ MSOP, which reduces board space by 50% and height by 40%.


  • Fully Specified for 3.3-V and 5-V Operation
  • Wide Power Supply Compatibility 2.5 V - 5.5 V
  • Output Power for RL = 8
    • 350 mW at VDD = 5 V
    • 250 mW at VDD = 3.3 V
  • Ultralow Supply Current in Shutdown Mode...0.15 µA
  • Thermal and Short-Circuit Protection
  • Surface-Mount Packaging
    • SOIC
    • PowerPAD™ MSOP

PowerPAD is a trademark of Texas Instruments.

View more

Parametrics Compare all products in Speaker amps

Audio input type
Speaker Channels (Max)
Power stage supply (Min) (V)
Power stage supply (Max) (V)
Output power (W)
Load (Min) (ohms)
THD + N @ 1 kHz (%)
Iq (Typ) (mA)
Control interface
Closed/open loop
Analog supply (Min) (V)
Analog supply (Max) (V)
Operating temperature range (C)
TPA321 TPA301
Analog Input     Analog Input    
Class-AB     Class-AB    
Mono     Mono    
2.5     2.5    
5.5     5.5    
0.35     0.35    
8     8    
1     1    
0.7     0.7    
Hardware     Hardware    
Closed     Closed    
2.5     2.5    
5.5     5.5    
85     85    
-40 to 85     -40 to 85    
Catalog     Catalog