DC1429A: LTC3642 45V, 50mA High Efficiency Synchronous Step-Down Converter
High efficiency 50mA step-down converter demo circuit (DC1429A) featuring the LTC3642, with a 4.5V to 45V input range and jumper-selectable 1.8V, 3.3V, or 5V outputs.
Overview
Demonstration circuit DC1429A showcases the LTC3642, a high-efficiency synchronous buck converter. It supports a wide input voltage range of 4.5V to 45V, with internal overvoltage protection capable of handling surges up to 60V. The circuit provides up to 50mA of load current and features an ultra-low 10μA quiescent current. The output voltage is jumper-selectable for 1.8V, 3.3V, or 5V. The design includes internal power switches and requires no external compensation, simplifying the configuration for low-power, high-voltage applications. The document includes a performance summary, setup procedures, and a complete bill of materials.
Use Cases
- Battery-powered systems
- Industrial control power supplies
- Automotive 4V to 60V surge protection
- Distributed power systems
- Low power handheld devices
Topics
Referenced Parts
LTC3642EDD
Linear Technology
I.C., Volt. Reg.
C3225X5R1H225MB
TDK
Cap., X5R 2.2uF 50V 20%
CRCW12064R70JNED
Vishay
Res., Chip 4.7 Ohm 0.25W 5%
LTC3642
Linear Technology
high efficiency step-down DC/DC converter featuring LTC3642
LTC3642-3.3
Linear Technology
VOUT ± 1.3% (LTC3642-3.3 Fixed 3.3V version)
LTC3642-5
Linear Technology
VOUT ± 1.3% (LTC3642-5 Fixed 5.0V version)
C3225X5R1H225MB
TDK
1 1 CIN Cap., X5R 2.2uF 50V 20% TDK C3225X5R1H225MB
CRCW12064R70JNED
Vishay
3 1 R4 Res., Chip 4.7 Ohm 0.25W 5% Vishay CRCW12064R70JNED
100uH
TDK
5 1 L1 Inductor, 100uH TDK VLCF5020T-101MR27
| 04023A220KAT2A | AVX | Cap., NPO 22pF 25V 10% |
| 04023D682MAT2A | AVX | Cap., X5R 6800pF 25V 20% |
| 12061C224MAT2A | AVX | Cap., X7R 0.22uF 100V 20% |
| 2501-2-00-80-00-00-07-0 | Mill-Max | Turret, Testpoint |
| EEU-FC2A680L | Panasonic | Panasonic part # EEU-FC2A680L, 68μF/100V |
| 2SN-BK-G | Samtec | Shunt, 2mm Ctrs. |
| TMM-102-02-L-S | Samtec | Jumper, 2pins 2mm Ctrs. |
| TMM-103-02-L-S | Samtec | Headers, 3 Pins 2mm Ctrs. |
| C3216X5R0J106M | TDK | Cap., X5R 10uF 6.3V 20% |
| VLCF5020T-101MR27 | TDK | Inductor, 100uH |
| CRCW04020000Z0EA | Vishay | Res/Jumper, Chip 0 Ohm 1/16W 1 AMP |
| CRCW04021M18FKED | Vishay | Res., Chip 1.18M 0.06W 1% |
| CRCW04021M47FKED | Vishay | Res., Chip 1.47M 0.06W 1% |
| CRCW0402280KFKED | Vishay | Res., Chip 280K 0.06W 1% |
| CRCW04022M00JNED | Vishay | Res., Chip 2M 0.06W 5% |
| CRCW0402475KFKED | Vishay | Res., Chip 475K 0.06W 1% |
| CRCW0402715KFKED | Vishay | Res., Chip 715K 0.06W 1% |
| 04023A220KAT2A | AVX | 1 0 CFFW (Opt) Cap., NPO 22pF 25V 10% AVX 04023A220KAT2A |
| 04023D682MAT2A | AVX | 4 1 CSS Cap., X5R 6800pF 25V 20% AVX 04023D682MAT2A |
| 12061C224MAT2A | AVX | 2 1 CIN1 Cap., X7R 0.22uF 100V 20% AVX 12061C224MAT2A |
| 2SN-BK-G | Samtec | 4 2 XJP1,XJP2 Shunt, 2mm Ctrs. Samtec 2SN-BK-G |
| TMM-102-02-L-S | Samtec | 3 3 JP2,JP3,JP4 Jumper, 2pins 2mm Ctrs. Samtec TMM-102-02-L-S |
| TMM-103-02-L-S | Samtec | 2 1 JP1 Headers, 3 Pins 2mm Ctrs. Samtec TMM-103-02-L-S |
| C3216X5R0J106M | TDK | 2 1 COUT Cap., X5R 10uF 6.3V 20% TDK C3216X5R0J106M |
| VLCF5020T-101MR27 | TDK | 5 1 L1 Inductor, 100uH TDK VLCF5020T-101MR27 |
| CRCW04020000Z0EA | Vishay | 5 1 R3 Res/Jumper, Chip 0 Ohm 1/16W 1 AMP Vishay CRCW04020000Z0EA |
| CRCW04021M18FKED | Vishay | 7 1 RFB2 Res., Chip 1.18M 0.06W 1% Vishay CRCW04021M18FKED |
| CRCW04021M47FKED | Vishay | 6 1 RFB1 Res., Chip 1.47M 0.06W 1% Vishay CRCW04021M47FKED |
| CRCW0402280KFKED | Vishay | 7 1 RFB4 Res., Chip 280K 0.06W 1% Vishay CRCW0402280KFKED |
| CRCW04022M00JNED | Vishay | 8 1 R1 Res., Chip 2M 0.06W 5% Vishay CRCW04022M00JNED |
| CRCW0402475KFKED | Vishay | 6 1 RFB3 Res., Chip 475K 0.06W 1% Vishay CRCW0402475KFKED |
| CRCW0402715KFKED | Vishay | 4 0 R2 (Opt) Res., Chip 715K 0.06W 1% Vishay CRCW0402715KFKED |
| 0603YC104MAT | AVX | Cap., X7R 0.1uF 16V 20% |
| 0603YC104MAT | AVX | 3 1 COUT1 Cap., X7R 0.1uF 16V 20% AVX 0603YC104MAT |
| LTC3642EDD | Linear Technology | I.C., Volt. Reg. |
| C3225X5R1H225MB | TDK | Cap., X5R 2.2uF 50V 20% |
| CRCW12064R70JNED | Vishay | Res., Chip 4.7 Ohm 0.25W 5% |
| LTC3642 | Linear Technology | high efficiency step-down DC/DC converter featuring LTC3642 |
| LTC3642-3.3 | Linear Technology | VOUT ± 1.3% (LTC3642-3.3 Fixed 3.3V version) |
| LTC3642-5 | Linear Technology | VOUT ± 1.3% (LTC3642-5 Fixed 5.0V version) |
| C3225X5R1H225MB | TDK | 1 1 CIN Cap., X5R 2.2uF 50V 20% TDK C3225X5R1H225MB |
| CRCW12064R70JNED | Vishay | 3 1 R4 Res., Chip 4.7 Ohm 0.25W 5% Vishay CRCW12064R70JNED |
| 100uH | TDK | 5 1 L1 Inductor, 100uH TDK VLCF5020T-101MR27 |