NJM2149M

Overview

The NJM2149M is a low voltage audio power amplifier designed for telephone applications. It operates on a single supply voltage ranging from 2V to 6V with a typical operating current of 2.2mA at 3V. The device delivers an output power exceeding 250mW into a 32-ohm load at 6V. It features a differential output configuration that eliminates the need for external coupling capacitors. The closed-loop gain is adjustable via two external resistors, and a Chip Disable (CD) pin allows for power-down mode with input muting.

Feature Summary

• Differential output design removes requirement for external coupling capacitors
• Integrated Chip Disable (CD) pin enables power-down mode with signal muting
• Closed-loop gain adjustment provided by two external resistors
• Operates within a wide supply voltage range of 2V to 6V

Applications

• Portable telephones
• Wireless telephones
• Button telephones
• Speaker amplifier circuits

Procurement Notes

Verify the specific package variant against the datasheet, as the NJM2149 series includes multiple packages such as DIP8, DMP8, SSOP8, VSP8, and TVSP8. Confirm that the M suffix corresponds to the DMP8 package type required for your PCB layout. Ensure the CD pin circuitry aligns with the specified high and low voltage thresholds for active and standby modes respectively.

Selection Notes

Select this component when designing low-voltage audio systems requiring minimal external passive components due to its capacitor-less differential output. Consider the 2.2mA typical operating current for battery-powered devices. Verify that the 250mW output capability meets the speaker impedance requirements, typically 32 ohms, and ensure the supply voltage stays within the 2V to 6V operational limits.

Part Context

The NJM2149 belongs to Nisshinbo Micro Devices' line of low voltage audio power amplifiers. It utilizes bipolar technology and is optimized for portable communication devices. The M suffix denotes the DMP8 surface-mount package. This model improves upon previous iterations like the NJM2135 by reducing thermal noise in power-down mode and enhancing high-band noise reduction capabilities.

Replacement Considerations

The NJM2149M serves as an upgrade over the NJM2135, offering improved noise performance. Other variants in the NJM2149 family include NJM2149D, NJM2149V, and NJM2149R, which differ primarily in package outline. Note that the NJM2149RB1 is listed as discontinued.