LTC1474/LTC1475 High Efficiency Switching Regulators Draw Only 10μA Supply Current
Design guide for LTC1474/LTC1475 step-down regulators featuring 10µA quiescent current, up to 92% efficiency, and 3V-18V input range for battery-powered applications.
Overview
This design document details the implementation of the LTC1474 and LTC1475, a family of ultralow quiescent current step-down regulators. These devices draw 10μA at no load and operate with an input range of 3V to 18V. The ICs integrate a P-channel MOSFET switch and support output currents up to 300mA. Features include Burst Mode operation for high efficiency across varying loads, programmable peak inductor current via an optional sense resistor, and an on-chip low-battery comparator. The document compares the LTC1474's RUN pin control with the LTC1475's pushbutton ON/OFF functionality and provides example circuits for 3.3V/250mA regulators and power extraction from 4mA to 20mA current loops.
Use Cases
- Battery-powered portable electronics
- 4mA to 20mA loop-powered systems
- Handheld devices requiring pushbutton power control
- Moderate current power management solutions
Topics
Referenced Parts
DO1608-334
Coilcraft
* COILCRAFT DO1608-334
LTC1474
Linear Technology
high efficiency step-down regulator ICs, the LTC1474 and LTC1475
LTC1474-3.3
Linear Technology
typical application circuit using the LTC1474-3.3 is shown in Figure 1
LTC1475
Linear Technology
high efficiency step-down regulator ICs, the LTC1474 and LTC1475
LTC1475-3.3
Linear Technology
LTC1475-3.3
THCS50E1E106Z
Marcon
** MARCON THCS50E1E106Z
CDRH73-101
Sumida
* SUMIDA CDRH73-101
CDRH74
Sumida
L1: SUMIDA CDRH74
400mA
Maxim
the peak inductor current to the 400mA maximum to
| MMBZ5242BL | Motorola | †† MOTOROLA MMBZ5242BL |
| MBR0530 | Motorola | MBR0530 0.5A Schottky diode used in Figure 1 is a good compromise |
| 1206ZG106Z | AVX | AVX 1206ZG106Z |
| TPSC107M006 | AVX | † AVX TPSC107M006 |
| TPSC475M035 | AVX | ** AVX TPSC475M035 |
| DO1608-334 | Coilcraft | * COILCRAFT DO1608-334 |
| LTC1474 | Linear Technology | high efficiency step-down regulator ICs, the LTC1474 and LTC1475 |
| LTC1474-3.3 | Linear Technology | typical application circuit using the LTC1474-3.3 is shown in Figure 1 |
| LTC1475 | Linear Technology | high efficiency step-down regulator ICs, the LTC1474 and LTC1475 |
| LTC1475-3.3 | Linear Technology | LTC1475-3.3 |
| THCS50E1E106Z | Marcon | ** MARCON THCS50E1E106Z |
| CDRH73-101 | Sumida | * SUMIDA CDRH73-101 |
| CDRH74 | Sumida | L1: SUMIDA CDRH74 |
| 400mA | Maxim | the peak inductor current to the 400mA maximum to |