Date: 16/02/2011

Ultra-small LDO voltage regulator chip from Seiko

Seiko Instruments has released the S-1312/1313 series, LDO voltage regulator chips featuring 850 mW power dissipation, thermal shutdown capability, high ripple rejection, and ultra-low 0.9-micro-ampere current consumption. This IC measures 0.8 x 0.8 x 0.4 mm in dimension and is the world's smallest LDO as per Seiko. This linear regulated power supply IC is suggested for applications such as smart phones, mobile phones, digital cameras, notebook PCs, hearing aids, and other battery operated portable device designs.

Thermal shutdown protection is built-in, automatically protecting the circuit when the junction temperature reaches 150 degrees C and restarts regulation when it drops to 120 degrees C. Overcurrent protection is also a built-in feature.

Current consumption is 0.9 micro amperes for S-1313 and 20 micro amperes for S-1312 and these devices provide ripple rejection of 75 dB (typical). Output voltage is maintained with accuracy of +/- 1.0%.

Though are small in package sizes these devices support automatic visual solder joint inspection, improving manufacturing yields and reliability. The package incorporates a heat sink capable of 850 mW dissipation (board size 40 x 40 x 0.8 mm, 4 layers, copper ratio 50%).

The outer lead design is such that it bears circuit board flexing and mechanical shock. This is particularly important for small consumer devices like smart phones that are subjected to constant use.

Both regulators are also available in SOT-23-5 and SC-82AB packages.