New Industry Products

Semtech Introduces Single-Cell AA/AAA, 555-Like Analog Timer with Battery-Safe Operation

November 08, 2010 by Jeff Shepard

Semtech Corp. announced a sub-1V analog timer platform which the company says revolutionizes the conventional 555 timer for low-voltage, battery-operated small appliances. The company states that the new SX8122 analog timer offers the best-in-class battery life via its intrinsic 0.9V operation, without the need for an external boost converter and inductor, saving board space and cost. It also adds low-voltage features to the legacy 555 timer, with one output that controls a dc motor or another continuous low-voltage element and another output that generates a pulse train to drive a high-brightness LED from a single battery. This combination of features makes the SX8122 well suited for a wide range of small consumer home and office appliances, such as electric toothbrushes, buzzers, toys, and LED pointers. The device also includes a voltage monitor to enable a simple USB charger for NiMH or NiCd supplied devices.

"The 555 timer is one of the most popular ICs ever, because it is easy to use, cost-effective and a proven performer," said Michel Chevroulet, System Engineering Manager for Semtech’s Advanced Communications and Sensing Group. "By embedding unique low-voltage features, the SX8122 extends the versatility of the 555 timer to drive smaller size, lighter weight, and lower cost in battery-enabled consumer products. The SX8122 is the industry’s first analog timer embedding low-voltage features for single AA/AAA cell-powered appliances."

The new Semtech SX8122 timer operates between 0.9 and 2V over the full industrial temperature range of -40 to +85°C, making it well-suited suited to run from one AA or AAA alkaline, NiMH or NiCd battery. The device has a continuous output that can be activated on the press of a button to control either a dc motor or other continuous low voltage function, as well as a burst output to drive a high-brightness white or green LED, or other feature requiring a voltage boost. The SX8122 timer is programmable via external resistors and a capacitor, similar to the legacy 555 analog timer but at 1V, and is designed for on/off button debouncing, delayed start-up functions, and analog programmable sequencing and time-out in toys and remote control applications.

The SX8122 is battery safe. It starts controlling I/Os at 0.6V, to eliminate unexpected behavior in the external components and prevent current drain during the start-up phase. It also features a battery overload indicator for slow NiMH or NiCd charger management. At power down (low battery), the I/Os are controlled again down to 0.6V and the current consumption is guaranteed less than 10µA over the full industrial temperature range to avoid battery leakage.

According to the company, the SX8122 is the only single–chip, application-specific solution that operates intrinsically from 0.9V, while managing the battery and providing precise timing. By directly providing dc and burst outputs, it can drive continuous loads, as well as loads with high threshold voltage.

Applications include a wide range of sub-1 V small consumer home and office appliances: 555-Timer/Analog Timer; Brushed DC Motor Control; Water Level Detection; Cell Phone Call Detector; Buzzer Control; LED Boost; Voltage Boost applications in products such as electric toothbrushes, shavers, automatic perfume dispensers, toys, LED pointers and LED torches.

The SX8122 is available immediately in production quantities and is priced at $0.36 each in 2,500-piece lots.