AS1706-T

Overview

The AS1706-T is a 1.6W bridged audio power amplifier from ams-OSRAM USA INC., designed for single-supply operation between 2.7V and 5.5V. It delivers 1.6W into a 4Ω load at 1% THD+N under 5V conditions, or 0.8W into an 8Ω load. The device features a bridge-tied load output stage eliminating external coupling capacitors. Key electrical characteristics include a shutdown supply current of 1µA, PSRR greater than 65dB at 217Hz, and an operating temperature range of -40°C to +85°C. It is housed in an 8-pin MSOP package.

Feature Summary

• Bridge-tied load (BTL) architecture enables differential driving of 4Ω and 8Ω speakers without output coupling capacitors.
• Integrated click-and-pop suppression circuitry minimizes audible transients during power-up and shutdown sequences.
• Low-power shutdown mode reduces quiescent consumption to 1µA when the active-low SHDN pin is pulled high.
• Built-in thermal-overload and over-current protection safeguards against short-circuit and excessive heat conditions.

Applications

• Battery-powered MP3 and CD players
• Mobile phones and PDAs
• Portable DVD players

Procurement Notes

Verify the specific ordering code AS1706-T to confirm the tape and reel delivery form and active-low shutdown logic. Ensure compatibility with the 8-pin MSOP footprint and validate that the system voltage remains within the 2.7V to 5.5V operational range. Confirm RoHS compliance status through official manufacturer documentation prior to final procurement.

Selection Notes

Select this component for applications requiring high efficiency and minimal external components in battery-operated devices. The active-low shutdown control suits systems where the enable signal is naturally high during standby. Consider the thermal dissipation requirements for continuous high-power operation into low-impedance loads.

Part Context

The AS1706 belongs to the AS1701/AS1706 family of 1.6W audio power amplifiers manufactured by austriamicrosystems AG. While functionally identical to the AS1701, it differs in shutdown polarity; the AS1706 utilizes an active-low shutdown mechanism, whereas the AS1701 uses an active-high configuration. Both share the same BTL topology and protection features.

Replacement Considerations

The AS1701 serves as a functional substitute within the same family, provided the design accommodates its active-high shutdown requirement instead of the AS1706's active-low logic. No other cross-manufacturer substitutes are confirmed in the provided datasheet.

FAQ

How does the shutdown logic differ between the AS1701 and AS1706?

The AS1706 features an active-low shutdown, meaning the SHDN pin must be connected to VDD to enter shutdown mode. In contrast, the AS1701 uses an active-high shutdown, requiring connection to GND.

What is the purpose of the CBIAS capacitor?

The bias bypass capacitor (CBIAS) improves Power Supply Rejection Ratio (PSRR) and Total Harmonic Distortion plus Noise (THD+N). It also serves as the primary component for click-and-pop suppression by controlling the rise and fall rate of the common-mode bias voltage.