Hot swap controller offers adjustable current limit

Milpitas, Calif. — Linear Technology Corp. has introduced the LTC4218 Hot Swap controller for protecting boards with load supply voltages ranging from 2.9 V to 26.5 V.

The LTC4218 enables safe board insertion and removal from a live backplane, using an external N-channel pass MOSFET in the power path to limit the inrush current during power up. An adjustable current limit allows users to vary the current limit threshold under various loading conditions, such as disk drive spin-up to normal operation. The wide operating voltage and adjustable current limit differentiate the LTC4218 from other low-voltage hot swap controllers, said Linear.

The LTC4218 features are tailored for use in RAID, server, telecom (i.e., ATCA, AMC, uTCA) and industrial applications. The load current is monitored using the voltage sensed across a current sense register and adjusting the MOSFET's gate-to-source voltage accordingly. A separate ISET pin allows users to adjust the 5% accurate (15 mV) current limit threshold during startup and normal operation as needed. Meanwhile, current foldback and power-good circuitry ensure that the switch is protected from excessive load current and indicates whether a power-good condition is maintained.

The LTC4218 also features current monitor and fault outputs, 2% accurate over-voltage and under-voltage protection, and an adjustable current limit timer. A dedicated 12-V version (LTC4218-12) is also available, which contains preset 12-V specific thresholds.

The LTC4218 offers a variety of ordering options. Commercial (“C”) and industrial (“I”) versions support operating temperature ranges from 0°C to 70°C and -from 40°C to 85°C, respectively. The LTC4218 is available in a 16-lead SSOP, while the LTC4218-12 is available in a 16-lead 5 x 3-mm DFN. Both devices are RoHS compliant.

Pricing: Starts at $2.65 each in quantities of 1,000.
Availability: Available now.
Product information: LTC4218

Linear Technology Corp. , 1-408-432-1900,

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