AS2524BF

Overview

The AS2524BF is a CMOS integrated circuit designed for A/B-line powered telephony applications, featuring a parallel interface controlled by standard dialers. It integrates DC and AC line adaptation with synthesized AC-impedance of 1000 ohms, alongside a speech circuit supporting handset and handsfree modes. The device incorporates softclipping, background noise monitoring, and loudspeaker amplification. Operating currents range from 15mA to 100mA in normal mode, reducing to 5mA with performance limitations. It is available in a 28-pin SOIC package or as a die.

Feature Summary

• Parallel interface control via xPD, xMUTE, and HF pins for simplified integration with common Taiwanese dialers
• Integrated loudspeaker amplifier supporting both loudhearing and full-duplex handsfree operation
• Automatic line loss compensation permanently activated for high-current line conditions
• Dual softclipping mechanisms in both handset and handsfree paths to prevent acoustic shock

Applications

• Enhanced handsfree feature phones with CallerID support
• Telephones equipped with extended displays
• Devices interfacing with standard Taiwanese dialers

Procurement Notes

Verify the specific suffix 'F' indicates the Dice-on-Foil (DOF) configuration rather than the standard SOIC package. Confirm that the permanent Line Loss Compensation setting aligns with the target application's line current requirements. Ensure the parallel interface logic levels match the connected dialer specifications.

Selection Notes

Select this component when a CPU-controlled serial interface is unnecessary and a standard dialer provides sufficient control signals. The AS2524BF is appropriate for designs requiring fixed gain settings without software programmability. Consider the AS2523 if dynamic gain adjustment or digital volume control is required instead.

Part Context

This part belongs to the AS2523/24 family developed by austriamicrosystems AG (now ams AG). The AS2524 variant specifically targets cost-sensitive applications using parallel interfaces, while the AS2524B adds automatic line loss compensation. The 'F' designation denotes the bare die form factor.

Replacement Considerations

AS2524B (SOIC package)

FAQ

How does the AS2524BF handle line loss compensation?

Line loss compensation is permanently activated in the AS2524BF. It decreases transmit and receive gains by 6dB during high line current ranges (45mA to 75mA) to maintain signal quality.

What is the default operating mode upon power-up?

The default operating mode is Handset mode. The device can be switched to Handsfree mode via the HF pin or configured for Power Down via the xPD pin.

Can the transmit and receive gains be adjusted digitally on the AS2524BF?

No, the AS2524BF uses a parallel interface with fixed gain settings. Programmable Tx/Rx gain requires the AS2523 variant, which utilizes a serial interface.