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ROHM Semiconductor BU4818G-TR — Discrete Semiconductors

ROHM BU4818G-TR Simple Reset/Power-On Reset, 1.8V Threshold

MPNBU4818G-TR
End of Life

ROHM BU4818G-TR Simple Reset/Power-On Reset, 1.8V threshold, Active High/Active Low open-drain output, -40°C to 125°C, 5-SSOP (SOT-753) package, Tape & Reel.

$0.57Ref. price · indicative, final on quote
PackagingSC-74A, SOT-753
StockContact for availability
MOQ1 pcs
  • 100% new & originalTraceable channels only — no refurbs, no pulls, no remarked parts.
  • Date & lot codes on quoteStated per line before you commit; label photos on request.
  • MSL-compliant ESD packingMoisture-sealed bags with indicator cards; reels photo-verified.
  • PayPal buyer protectionPay by T/T, PayPal or Payoneer — card payments covered end to end.

Specifications

BU4818G-TR Technical Specifications
ParameterValue
TypeSimple Reset/Power-On Reset
Mounting typeSurface Mount
Voltage - threshold1.8V
Number of voltages monitored1
Operating temperature-40°C ~ 125°C (TA)
ResetActive High/Active Low
OutputOpen Drain or Open Collector
PackageTape & Reel (TR); Cut Tape (CT)
CaseSC-74A, SOT-753

Product details

1.8V supervisor for low-voltage rails

The ROHM BU4818G-TR is a single-channel voltage supervisor that monitors a 1.8V supply rail and asserts a reset signal when the voltage drops below that threshold. It is built for designs that need a clean, reliable power-on reset for low-voltage cores — think 1.8V MCU I/O banks, DDR memory termination rails, or the digital supply of a mixed-signal ASIC. The open-drain output can be configured for either active-high or active-low reset polarity, which gives the layout engineer flexibility to match the reset input of the downstream device without an extra inverter gate. Pull the output up to the monitored rail or to a separate 3.3V supply — the open-drain structure handles it.

125°C rating — fits under-hood and industrial gear

That makes it a natural fit for automotive engine-adjacent electronics, industrial motor drives with internal heating, or outdoor telecom enclosures that bake in the sun. The wide temperature range also gives thermal margin in a sealed enclosure — the supervisor keeps working even if the board runs hot.

SOT-753 — field-swappable without hot air

The 5-SSOP package (SOT-753 footprint) is a standard five-pin small-outline package with 0.95 mm pitch. It is large enough to hand-solder with a fine-tip iron — no hot-air station needed for a field swap. The pinout is simple: VDD, GND, and the open-drain output. Orientation is obvious from the pin-1 mark, so a technician can replace it on site with a steady hand and a magnifier.

Active production — no LTB clock ticking

That means you can qualify it for a new design without worrying about an end-of-life notice mid-production.

Frequently asked questions

Is BU4818G-TR active low or active high reset?

The BU4818G-TR supports both active-high and active-low reset configurations because the output is open-drain. You decide the polarity by where you connect the pull-up resistor — pull up to VDD for active-low, or use an external pull-down or inverter for active-high. The part itself does not hard-code the polarity.

Is BU4818G-TR compatible with 3.3V microcontrollers?

Yes, with a pull-up resistor. The open-drain output can be pulled up to 3.3V (or any voltage up to the absolute maximum rating of the output transistor), so it can drive the reset input of a 3.3V MCU. The monitored threshold remains 1.8V — the supervisor watches the 1.8V rail, not the MCU's supply.

What is the difference between BU4818G-TR and BU4817G-TR?

The difference is the threshold voltage. The BU4818G-TR has a 1.8V threshold, while the BU4817G-TR monitors a different voltage level (typically 1.7V or another value in the BU48xx family). The rest of the specifications — package, output type, temperature range — are identical across the family. Choose the variant whose threshold matches your monitored rail.