Smallest 18-V eFuse power switch offers system protection
The devices aim to reduce solution size and extend battery life in portable and adapter-powered devices, and enterprise and client solid state drives (SSDs).
Enterprise SSDs are reading and writing more data than ever before, which is driving a requirement for increased speed and reliability in smaller form factors. TI’s TPS25940 and TPS25942 integrated circuits include back-to-back FETs to provide bidirectional current control, while reducing system size by 50 percent compared to discrete solutions. These smart eFuse ICs save board space by maintaining over/under voltage threshold accuracy of two percent, eliminating the need for a separate supply voltage supervisor chip.
The TPS25940 eFuse power switch integrates DevSleep mode, which enables hosts and devices to completely hibernate an SSD serial ATA (SATA) interface to reduce power consumption to less than 5 mW. The TPS25942 eFuse power multiplex (MUX) integrates an enable block function which allows the system to select between non-ideal diode mode and ideal diode mode.
The TPS2594x extend battery life and reduce power loss. In addition to DevSleep mode, the smart-eFuse devices integrate an active mode to reduce power consumption by providing an internal low-resistance switch (42 mOhm typical).
The switches offer fast short-circuit response of 200 ns minimizes bus droop and supply stress during short-circuit events and allow two supplies of equivalent voltage to be designated primary and secondary without turning off the overcurrent protection NFET of either, which reduces holdup capacitor requirements by up to 70 percent.
TI also introduced a new power management unit (PMU) with six integrated buck regulators designed for the SandForce SF3700 SSD controllers for notebooks and PCs. The LM10692 provides phase-shifted operation at 2-MHz switching frequency to reduce the input-current ripple. In addition, the integrated PMU minimizes inductor and capacitor size to save valuable board space. Using TI’s LM10692 and MSP430 with SandForce’s SF3700 controller reduces system size to a tiny 13.5-mm by 9.3-mm footprint. As part of this collaboration, TI joined the SandForce Trusted program in order to provide premium support and enable faster time-to-market for customers using TI solutions with the SandForce controller.
Availability and Pricing
The SSD power management devices are shipping in volume production in the following package options and prices in 1,000-unit quantities:
TPS25940 eFuse power switch: 20-pin, WQFN package at $0.85.
TPS25942 eFuse power MUX: 20-pin, WQFN package at $1.10.
LM10692 PMU: 36-pin, VQFN package at $2.80.