These four examples of voltage regulators, designed by Linear Technology, fit particular handheld device applications.
- Synchronous step-down switching regulator
The LTC1878 is a good combination of a very low IQ, an ultra-low ISD and a high efficiency under load (h). For example, the LTC1878 has 10-mA IQ, 1-mA ISD and up to 96 percent h. It is available in a small MSOP package and switches at 550 kHz, resulting in regulator solution sizes as small as 0.4 inch2. The LTC1878 can supply up to 600 mA of load current.
- Step-down regulator
An example of a step-down regulator is the LTC1701, which provides extremely small regulator solution sizes. The LTC1701 is available in a very small SOT-23 package and switches at a very high 1-MHz switching frequency. That results in solution sizes as small as 0.3 inch2. However, it has higher IQ (135 mA) than LTC1878 and has 2 percent to 5 percent lower efficiency (h) under typical operating conditions. The LTC1701 can supply up to 500 mA of load current.
- Charge-pump regulator
The LTC1503-2 is a charge-pump regulator IC that is available in a small MSOP package and needs only four external capacitors to form a complete regulator solution that is as small as 0.075 inch2. The efficiency of LTC1503-2 is about 5 percent to 10 percent lower than comparable switching regulators in most operating conditions. It has a low IQ of 25 mA and a very low ISD of 5 mA. The LTC1503-2 can supply up to 100 mA of load current.
- LDO regulator
The LT1761 is an LDO regulator that supplies up to 100 mA of load current. It is available in a very small SOT-23 package and needs only two external capacitors to form a complete regulator solution. Its solution size is as small as 0.05 inch2.
For 3.3-V to 2.5-V conversions, the maximum efficiency that can be achieved using LT1761 is roughly 75 percent. The LT1761 has a low IQ of 20 mA and an ultralow ISD of 0.1 mA.
See related chart