What kind of low-dropout linear regulator (LDO) is the LT3045?

Moderator recently on the Internet did not intend to see some netizens talking about the difference between good batteries and poor batteries, carefully looked at the netizen's description, he thinks that the minimum noise is lithium batteries, is that true?

As we all know, battery noise can be very large, and of course it can be small. But to say minimum noise, it must not be a battery. The moderator can now bring everyone together to calculate -

When a lithium polymer battery is under 3.7V, 500mA load, the battery noise is 2.7μV;

When the two dry cells are strung together at 3V, 500mA, the noise is 7.1μV.

how about it? It seems to be quite small. It is because it has a good noise, so everyone thinks that the battery is relatively clean, as a classic benchmark. But the benchmark pursues initial accuracy and long-term stability, so this does not mean that its noise is the lowest.

Looking at the low-dropout linear regulator (LDO) LT3045 at 3.7V, 500mA load, the battery noise is how much?

0.8μV is obviously lower than the noise of one battery.

What kind of low dropout linear regulator (LDO) is the LT3045?

The LT3045 is an ultralow noise, ultra-high power supply ripple rejection (PSRR), low dropout voltage linear regulator that is the larger output current version of the popular 200mA LT3042 ultralow noise LDO. The LT3045 is uniquely designed to produce ultra-low noise of only 2nV/√Hz at 10kHz and 0.8μVRMS overall output noise over a wide 10Hz to 100kHz bandwidth. Its low and high frequency PSRR performance is excellent. The low-frequency PSRR exceeds 90dB at 10kHz and the high-frequency PSRR exceeds 70dB at 2.5MHz, which improves noise or high-ripple input power.

It uses Linear's proprietary LDO architecture, which follows a precision current source reference followed by a high-performance unity-gain buffer, resulting in almost constant bandwidth, noise, PSRR, and load regulation without being affected by the output voltage. It is easier to pass parallel connections to further reduce noise, increase output current, and spread heat on the PCB.

In the 1.8V to 20V input voltage range, the LT3045 delivers up to 500mA of output current at 260mV dropout voltage at full load. The output voltage range is 0V to 15V, and the output voltage tolerance is very accurate ±2% over the entire voltage, load, and temperature range. The device's wide input and output voltage range, large bandwidth, high PSRR, and ultra-low noise performance are ideal for powering noise-sensitive applications such as PLLs, VCOs, mixers, LNAs, very low noise instruments, and high speed/high accuracy Medical applications such as data converters, imaging and diagnostics, precision power supplies, and post regulators as switching power supplies.

The LT3045 operates with a very small, low cost 10μF ceramic output capacitor, optimizing stability and transient response. A single resistor sets a precise external current limit (±10% over the temperature range). A single SET pin capacitor reduces output noise and provides a baseline soft start feature that prevents output voltage overshoot at turn-on. In addition, the device's internal protection circuitry includes reverse battery protection, reverse current protection, internal current limit with foldback, and thermal limit with hysteresis. Other features include a fast start function (useful if a capacitor with a very large capacitance of the SET pin is used) and a power good flag with a programmable threshold to indicate that the output voltage is stable.

The LT3045 is available in thermally enhanced 10-lead 3mm x 3mm DFN (LT3042 pin compatible) and 12-lead MSOP packages. The footprint of both packages is very compact. The E-grade and I-grade versions are available from stock and the operating junction temperature range is –40°C to 125°C. Future high-temperature H-grade versions will specify a temperature range of –40°C to 150°C. These devices are available from stock, and the E-grade version is priced at $2.80 per piece in 1,000-piece quantities.