Headphone Amplifier is capable of operation from 0.93 V.

Rohm Electronics USA LLC Aug 30, 2010

Press Release Summary:

Accommodating compact, portable equipment put to continuous use that requires extended operating times from one battery, BU7150NUV supports operating power supply ranges of 0.93-3.5 V and 1.03-3.5 V. Automatic startup sequence control circuit, power ON reset function, and clicking/popping noise reduction circuit promote optimal performance, while 1 mA operation promotes battery life. Other features include thermal shutdown circuit and selectable BTL connection.

Original Press Release:

Low Power Headphone AMP

Overview
Compact portable equipment put to continuous use, such as IC recorders, electronic dictionaries, and portable audio players, require longer operating times from a single battery. To meet this need ROHM offers the BU7150NUV headphone amp capable of operation from only 0.93V.

Key Features

Wide operating power supply voltage range
(0.93V to 3.5V, Ta=0ÂºC to 85ÂºC)
(1.03V to 3.5V, Ta=-40ÂºC to 85ÂºC)

Selectable modes: BTL for monaural speakers, single-end stereo headphone

Unity gain results in stable operation

Clicking/popping noise reduction circuit built in

Shutdown mode (low power consumption mode)

Built-in mute function (high-speed turn ON upon mute release)

Integrated thermal shutdown circuit

Power ON reset circuit not affected by the supply voltage startup slew rate

Compact package

Key Feature 1: Wide operating voltage range (0.93V to 3.5V) enables operation from one or two batteries
The wide operating voltage range supports operation from one or two batteries. In addition, BTL connection allows the BU7150NUV to be used as a high-output monaural speaker amp. Additional features include an automatic startup sequence control circuit, power ON reset function, and clicking/popping noise reduction circuit for high-performance operation.

Key Feature 2: Low voltage, low current (1mA) operation results in longer battery life
The BU7150NUV features low 1mA current consumption and a wide voltage range (0.93V to 3.5V). When operating from a single battery, conventional headphone amps require a step-up circuit, which increases power consumption as well as loss (through step-up operation). In contrast, the BU7150NUV eliminates the need for a step-up circuit, reducing power consumption for longer battery life.

                             Conventional Class AB Amp      BU7150NUV

Supply Voltage (typ)                    3V                     1.5V

No-Signal Current                      5.0mA                   1.0mA

Power Consumption                     15.0mW                   1.5mW

DC/DC Efficiency                        90%                      -

Total Power Consumption               16.7mW                   1.5mW

Key Feature 3: Built-in startup sequence circuit reduces load and controls clicking noise
A startup sequence circuit is built in to ensure high fidelity audio output during ON/OFF operation. Clicking/popping noise reduction is automatically performed, elminating the need for microcontroller control. In addition, the power ON reset function is not dependent on the supply voltage startup slew rate, simplifying use considerably.