SI8540-B-FWR Silicon Labs High-Side Current Sense Amplifier SOT-23-5 | JTDZ Tech

SI8540-B-FWR — Overview

SI8540-B-FWR by Silicon Labs is a component in the Current Sense Amplifiers - High-Side, Unidirectional category, supplied by Shenzhen Jinteng Electronics Technology Co., Ltd. (JTDZ Tech) — an independent distributor serving OEMs, ODMs and EMS providers worldwide.

The SI8540-B-FWR is a complete, unidirectional high-side current sense amplifier from Silicon Labs, supplied taped and reeled in a SOT-23-5 package. It draws its bias current directly from the high-side line it monitors, so no separate supply rail is required, and it measures load current from 0.1 A to 10 A by sensing the voltage across an external sense resistor or PCB trace, from DC to 20 kHz, with 0.2% full-scale accuracy (typical). The output is a current signal proportional to the measured current and is converted to a ground-referenced voltage with a single external resistor (R_OUT), which lets the designer set the gain by choosing external resistor ratios. Operating range is +5 V to +36 V over −40 °C to +85 °C, with 85 dB power-supply rejection, 90 µA maximum supply current and 9 µA shutdown current — well suited to battery chargers, smart battery packs, backup systems, DC motor control and current-control loops. Note that this part has been discontinued by the manufacturer, so availability is limited to remaining channel stock; the Silicon Labs power and isolation product lines are now part of Skyworks Solutions.

Key specifications

Datasheet parameters

Parameters above are transcribed from the manufacturer datasheet for reference only. Confirm the current datasheet revision and your application conditions before design-in.

Typical applications

• Battery chargers and smart battery packs
• Backup systems and current-control loops
• DC motor control
• Notebook and portable power management
• Cellular infrastructure equipment and high-end routers
• Automotive current monitoring

Stock, packaging and availability

Stock levels move quickly, and this part is discontinued. Confirm current availability, quantity and date code with our team before ordering.

Need a quote for SI8540-B-FWR? Send your target quantity, destination and required date code to our sales team — we reply with price, stock and lead time within 2 working hours.

Browse the full Amplifiers / Data conversion collection for more current sense and signal-conditioning devices, or the Silicon Labs collection for the rest of the line.

Other Silicon Labs parts in stock

Frequently asked questions

What does the SI8540-B-FWR do?

The SI8540-B-FWR is a unidirectional high-side current sense amplifier. It senses the voltage across an external shunt resistor or PCB trace on the high side of a supply and outputs a proportional current that a single resistor converts to a ground-referenced voltage. It measures 0.1 A to 10 A from DC to 20 kHz with 0.2% typical full-scale accuracy.

Does the SI8540-B-FWR need a separate supply rail?

No. The device draws its bias current from the high-side line it monitors, which removes the need for an external supply. It operates over +5 V to +36 V with 90 µA maximum supply current and 9 µA in shutdown.

What package is the SI8540-B-FWR supplied in?

SI8540-B-FWR is supplied in a SOT-23-5 package, taped and reeled (FWR suffix). Always confirm the package, pinout and layout against the current manufacturer datasheet before design-in.

Is the SI8540-B-FWR still in production?

No. Silicon Labs has discontinued the Si8540, and the Silicon Labs power and isolation product lines now sit within Skyworks Solutions. Stock offered here is remaining channel inventory — confirm the date code and quantity you need before committing.

Is the SI8540-B-FWR original and genuine?

Yes. We supply SI8540-B-FWR as original, unused stock sourced through long-verified, traceable channels. Traceability documents, inspection reports and photos of the actual goods can be provided on request before you commit.

Do you quote volume orders for the SI8540-B-FWR?

Yes. We quote volume pricing, available quantity and lead time within 2 working hours, and we can consolidate SI8540-B-FWR with other line items into a single shipment.

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