NXP Semiconductors today announced its entry into the low drop-out voltage regulator (LDO) market with the launch of a chip that drops only 60mV at 200mA, in a 0.76x0.76mm package.
Called LD6806CX4, "due to the low drop-out voltage, it is still able to support an SD card with a mandatory 2.9V if the battery of a smartphone goes down to 3.0V", said the company.
Output noise on from the LD6806 series is 30µVrms and, according to an NXP statement, stand-by current is typically 100nA although the data sheet does not currently have a typical figure, simply stating 1µA max.
ESD rating is 10kV (human body model) and the chip also features thermal shutdown and a current limiter.
Package options include the LD6806F in a larger 1.45x1.0x0.5mm package with an inferior drop-out voltage compared with the smaller package.
There is also a 5pin SOT753 2.9x1.5x1.0mm version.
60mV is right there amongst the lowest drops for 200mA parts - although Diodes has had the 60mV ZLDO500 since 1997, albeit in a much larger package with in 18V input and internal bipolar pass transistor - compared with p-channel mosfets (and inputs around 6V max.) in the other parts discussed here.
More recent tiny very low drop regulators include Texas Instrument's 0.8x0.8mm TLV705 series which drops 105mV at 150mA and 145mV at 200mA.
In this case the firm emphasises accuracy - typically 0.5% (NXP's is 3%), and power supply rejection ratio (PSRR) of 70dB at 1kHz, compared with 55dB from NXP.
TI has worked to keep the output capacitor value down, with 0.1µF needed for stability in this case. For comparison, NXP needs 0.7µF min, and recommends 1µF to make sure tolerances do not take it below the minimum.
Shut down current is 1µA.
Quiescent current for the NXP LDO is 70µA no load, rising to 155µA typical at 200mA out. TI's ranges from 55 to 315µA over the same output range.
The TI chip also comes in a suffix P variant with a switched output resistor for discharging capacitors on the output in shut-down - making sure the load is properly off.
In February, Analog Devices also emphasised PSRR for wireless mobile application in its ADP160, 1, 2 and 3 low-quiescent LDOs.
In these devices, ADI has really gone to town on tail current, cutting it to 50nA in shut-down, 560nA quiescent, and 42µA at 150mA (maximum) output - these are all typical figures.
PSRR is 70dB at 60Hz and 50-60dB at 1kHz.
60Hz is included because this chip is aimed at power meters as well as mobile use.
"These LDOs are optimised for use with 1µF ceramic capacitors," said ADI product line manager Walt Heinzer.
Amongst versions are fixed and variable output types, and well as variants with a switched output discharge resistor.
Fixed output versions are available in 1x1mm size, whereas the variable types need a larger five pin package.
