Analog Devices which recently acquired Linear Technology Corporation, announces the LTM4645, a 25A step-down μModule® (power module) regulator with the ability to current share multiple independent devices (N) where at least one LTM4645 is used as backup (+1) to ensure power availability if one device in this N+1 arrangement detects a fault and must be disconnected. For example, a 75 A, 1 V load such as an ASIC requires three LTM4645s for 75 A (= 3 × 25 A) total. For system resilience, one extra LTM4645 is added as a backup in 3+1 fashion, resulting in four LTM4645s current shared to deliver 75 A if one fails. In the event of a faulty operation of one regulator, the device signals an upstream hot swap controller to disconnect itself from the power path while the remaining three LTM4645 regulators maintain uninterrupted operation. Applications benefiting from the LTM4645’s N+1 redundancy feature include data centers, aerospace, banking transactions and cloud-based systems where improved system safety and integrity are top priority.
The LTM4645 operates from 4.7 V to 15 V input supply and regulates an output voltage adjustable from 0.6 V to 1.8V. Synchronous step-down operation delivers 25 A at 1 V from 12 VIN with 86% efficiency, 3.5 W power loss and 41 °C rise (no airflow, no heat sink). The device is offered in a 9 mm × 15 mm × 3.51 mm BGA package and includes the inductor, MOSFETs and DC/DC regulator IC. With a differential remote sense amplifier to compensate for voltage droop caused by PCB trace resistance and tested electrical parameters from –40 °C to 125 °C, the output voltage total DC accuracy is guaranteed at ±1.2%. The LTM4645 has several safety functions such as output overvoltage protection, output overcurrent protection, and an onboard temperature monitoring diode. The propagation delay from time of failure device turn-off is less than 200 ns.
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| Typical Application. |
The LTM4645 is rated for operation from –40 °C to 125°C. Up to 6 devices can current share for 150 A of load current. Power loss is only 3.5 W for 12 V input to 1 V output at 25 A load. For 12 V input, 1 V output conversion, full power is delivered up to 75 °C (0LFM, no heat sink) and at 85 °C derating of load current is 20 A. 1,000-piece pricing starts at $26.23 each.
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| Efficiency vs Output Current at 1 V Output. |
Summary of Features: LTM4645
- 4.7 V to 15 V Input Voltage Range
- 0.6 V to 1.8 V Output Voltage Range
- 25 A DC Output Current
- ±1.2% Total DC Output Voltage Error from –40 °C to 125 °C
- Supports High Reliability N+1 Phase Redundancy
- 9 mm × 15 mm × 3.51 mm BGA Package
