AS1701

Overview

The AS1701 is a 1.6W bridged audio power amplifier from ams-OSRAM USA INC., operating on a single 2.7V to 5.5V supply. It delivers 1.6W into a 4Ω load and 0.8W into an 8Ω load at 1% THD+N under 5V operation. The device features greater than 65dB PSRR at 217Hz, low-power shutdown current of 1µA, and integrated thermal and over-current protection. It utilizes an 8-pin MSOP package with an active-high shutdown pin.

Feature Summary

• Bridge-tied load (BTL) architecture eliminates the need for output coupling capacitors
• Integrated click-and-pop suppression circuitry minimizes audible transients during power-up and shutdown
• Low-power shutdown mode reduces quiescent current consumption significantly
• Built-in thermal-overload and short-circuit protection ensures operational reliability

Applications

• Audio front-ends for battery-powered MP3 and CD players
• Mobile phones and PDAs
• Portable DVD players and hand-held battery-powered devices

Procurement Notes

Verify the specific ordering suffix when purchasing. The standard AS1701 part number typically corresponds to tube packaging, while the -T suffix indicates tape and reel delivery. Confirm that the active-high shutdown logic matches your system design requirements before finalizing procurement.

Selection Notes

Select this component for applications requiring high efficiency and minimal external components in a compact form factor. Ensure the load impedance aligns with the desired output power specifications. Verify that the input signal frequency range does not require extensive low-frequency filtering beyond the internal capabilities.

Part Context

This device belongs to the AS170x series of 1.6W audio power amplifiers manufactured by austriamicrosystems AG. It shares architectural similarities with the AS1706 but differs in shutdown pin polarity. The series is designed for portable consumer electronics where space and power efficiency are critical constraints.

Replacement Considerations

The AS1706 serves as a functional substitute within the same family. Designers must account for the difference in shutdown pin logic: the AS1701 requires an active-high signal, whereas the AS1706 uses an active-low configuration.

FAQ

How is the gain of the AS1701 configured?

The gain is set by external feedback resistors RF and RIN according to the formula Av = 2 x (RIN / RF). Optimum output offset is achieved when RF equals 20kΩ.

What is the function of the BIAS pin?

The BIAS pin provides a DC bias bypass connection. It is internally connected to the non-inverting input of one amplifier and should be connected to the non-inverting input of the other for proper signal biasing and click-and-pop suppression.