25nA quiescent current in LDO doubles battery life

25nA quiescent current in LDO doubles battery life

New Products |
By Nick Flaherty

Texas Instruments (TI) has launched a a low-power low-dropout (LDO) linear voltage regulator with a quiescent current (IQ) of under 25 nA, one-tenth that of other small devices.

The TPS7A02 has the low IQ control at light loads even in dropout conditions, allowing engineers to at least double the battery life of their applications. This is combined with transient response of 5us for faster wake-up.

“Getting down to the point of a handful of nanoamps of quiescent current has been a challenge historically and we have been looking at where we wanted ot strategically invest and IQ was key,” said Mike Beckman, general manager of the linear power business unit at TI. “The low IQ and fast transient response of 5us for 1 to 50mA – that’s the hardest thing to trade off,” he said. “Most of the design time and effort has been on the band gap pass FET and the air amplifier, optimising these blocks and how they interact,” he said. 

The TPS7A02 features Dynamic Mode, which adjusts IQ while the device continuously monitors the load current in order to adapt the internal circuitry to maximise current efficiency over load. This provides the transient response with minimal output capacitance and quiescent current.

The chip will be available in a chip scale package measuring 0.65 x 0.65mm, a 70 percent shrink on the previous device, as well as common industry packages for pin-to-pin drop-in replacement in existing designs.

Battery life is a key parameter for designs in the Internet of Things (IoT). Using the TPS7A02 in wireless video doorbell and security camera designs, engineers can achieve 24 months or more of battery life, which is up to four times the industry standard. The shutdown current of 3 nA also extends battery shelf life by as much as five times in portable medical and wearable applications. “For 99.9% of their life, these devices are in a standby state, and it’s that standby state that deictates the battery lifetime,” said Beckman. “Shelf life is also important for consumer and for industrial applications.”

Pre-production samples of the TPS7A02 are now available through the TI store in a 4-pin small outline no-lead (X2SON) package measuring 1 mm by 1 mm. A 5-pin small outline transistor (SOT-23) package measuring 2.9 mm by 1.6 mm will become available later this year. In addition, a 4-pin die-size ball grid array (DSBGA) package measuring 0.65 mm by 0.65 mm will become available in early 2020. Pricing starts at US$0.49 in 1,000-unit quantities. The universal LDO linear voltage regulator evaluation module, MULTIPKGLDOEVM-823, is available for US$20.


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