AP1158ADS

Overview

The AP1158ADS is an active filter IC designed for low-frequency noise reduction in audio and precision systems. It operates within a voltage range of 2.1V to 14V, delivering up to 150mA output current with a typical quiescent current of 65µA. The device provides 66dB ripple rejection at 1kHz and achieves an output noise of 60nV/√Hz at 1kHz. It features a built-in thermal shutdown circuit and supports on/off control via the CONT terminal. The component is housed in a SOT-23-5 package and functions effectively as a low-dropout regulator when paired with an external reference.

Feature Summary

• Active filtering capability replaces discrete RC or LC filters to save mounting area
• Built-in thermal shutdown protection ensures operational safety
• Supports low-noise applications using small ceramic capacitors
• On/Off control functionality with high-active logic level

Applications

• RF power supplies for PLL, VCO, Mixer, and LNA
• Low noise image sensor units in digital still cameras
• High speed/high precision A-D and D-A converters
• Medical equipment requiring stable power rails
• Audio equipment acting as active noise filters

Procurement Notes

Verify the specific suffix against the ordering guide to confirm package type. Ensure input voltage does not exceed absolute maximum ratings during operation. Confirm capacitor ESR values fall within the stable operation area defined in the datasheet charts. Check thermal derating curves if operating near maximum temperature limits.

Selection Notes

Select the AP1158ADS when low-frequency noise suppression is critical. Consider the required output current and input-output voltage drop (VDROP) set by RFIL. Evaluate the stability requirements for the chosen output capacitor ESR. Ensure the application benefits from the active filter topology over passive components.

Part Context

The AP1158ADS belongs to AKM's active filter IC series, distinct from standard linear regulators due to its internal error amplifier and filter terminal. It is part of the broader AP115x family, which includes variants like the AP1152 and AP1153. This specific model focuses on noise reduction rather than fixed voltage regulation without external references.

Replacement Considerations

Public confirmed substitute part numbers are not available in the provided documentation. Verify compatibility with existing PCB layout and external component values if considering alternative active filter ICs.

FAQ

How is the output voltage drop (VDROP) determined?

VDROP is set by the resistor connected between VIN and the FIL terminal (RFIL). The formula is VDROP = RFIL × 0.6µA + VOFFSET.

What is the function of the CONT terminal?

The CONT terminal controls the On/Off state. A voltage greater than 1.8V turns the device ON, while less than 0.4V turns it OFF.

Can the AP1158ADS be used as a standard LDO regulator?

Yes, it can be used as a low I/O voltage/low noise regulator, but it requires an external reference voltage to set the output level.