1.2V to 3.6V Dual Input/Dual Output LDOs for AA or AAA Batteries

New Products Apr 01, 2019 by Scott McMahan

Diodes Incorporated announced the AP7345D family of dual low-dropout (LDO) voltage regulators that offer high power supply rejection ratio (PSRR) and low quiescent current, making them suitable for applications powered by primary cells such as AA or AAA batteries. The AP7345D offers high output voltage accuracy, low RDS(on), high PSRR, and low output noise. The family comprises 22 devices covering a range of fixed dual-input/dual-output voltages between 1.2V and 3.6V, with an accuracy of ±1%.

With such a comprehensive range, the AP7345D family can address a wide variety of battery-powered applications. Its low power consumption and line and load transient response make the AP7345D suited for low power handheld communication equipment. Applications for the family of LDOs include TVs, monitors, set-top-boxes, computing, and surveillance. Other potential applications include smartphones/PADs, RF supplies, cameras, portable video, portable media players, wireless adapters, and wireless communication.

The AP7345D provides independent voltage input with an enable pin for controlling the output. This arrangement provides for more flexibility when designing the power source for applications. Within about 10µs of the EN pin changing state, each channel switches off or on. If output control is not required, the EN pin on each channel can also be tied high.

The AP7345D family features a PSRR of 75dB at 1kHz, across the full output voltage range. The input voltage range extends from 1.7V to 5.25V and each of the two channels is guaranteed to deliver up to 300mA. The inclusion of short-circuit protection ensures the LDO does not sustain damage in the event of a short circuit on either of the output voltage rails.

Functional block diagram (Click on image to enlarge)

The addition of an LDO enables more of the primary cells’ voltage to be used, extending the useful lifetime between battery changes. In addition, an LDO with high PSRR ensures a steady and regulated supply voltage for sensitive integrated circuits.

Each regulator includes a voltage reference, error amplifier, current limit circuit, and an enable input to turn on/off output. With the integrated resistor network, fixed output voltage versions can be delivered.

The AP7345D comes in a X2-DFN1612-8 package, providing a small PCB footprint to enable high levels of power density.