Torex – New 300mA high-speed low-noise CMOS LDO in 1mm x 1mm package (XC6223)Nov 30 2009 - Semiconductors [More Semiconductors Articles]
Available in the tiny USPQ-4 package (1mm x 1mm x 0.4mm), as well as in standard SSOT-24, SOT-25 and SOT-89-5 versions, the new XC6223 Series of voltage regulators, from Torex Semiconductor, offers ultra-fast load transient response performance – PSRR (power supply rejection ratio) is 80dB at 1kHz, and the devices offer protection against inrush current.
The fast, low dropout voltage regulators provide a highly-stable, low-noise supply that meets the demands of most battery-driven circuits, says the company.
An LDO doesn’t normally use a soft-start circuit so at start up, the output voltage rises very quickly after the input voltage is applied. This can cause high peaks of inrush current. With a standard LDO, there is no inrush current protection. So the inrush current will only be limited by the current limit of the LDO (assuming that the LDO has a current limit) and if that limit is already quite high then the potential inrush current can also be high.
With a built-in protection circuit, inrush current is kept to a relatively low value without compromising on the output current capability of the LDO.
For applications that are very sensitive to inrush current, but where a relatively high output current is still required, it is possible to use the XC6223 series.
Due to its inrush current protection circuit, the XC6223E/F/G/H will limit the inrush current to less than 150mA typical, thus improving the reliability of the system. At the same time, the XC6223 can source up to 300mA of output current.
Output voltage can be factory set anywhere from 1.2V to 4V in 50mV steps, and the operating voltage range is from 1.6V to 5.5V. The LDO is also compatible with low ESR ceramic capacitors, which give added output stability. The new series also offers low dropout voltage – typically 200mV with a 300mA load (VOUT=3V).
An over-current protection circuit and a thermal-shutdown circuit are also built in. The over-current protection circuit will operate when the output current reaches its limit current level. When the junction temperature reaches its limit temperature (150C), the thermal-shutdown circuit takes control, it then releases at 120C.
The CE (chip enable) function enables design engineers to turn off the output, putting the device into standby mode, thereby greatly reducing power consumption. In addition, for the XC6223B/D/F/H versions, the electric charge at the CL capacitor is discharged via the internal auto-discharge switch, ensuring that the VOUT pin drops down to ground quickly.More news from Torex Semiconductor