MAX809LEUR+T

The MAX809LEUR+T is a microprocessor supervisory/reset circuit from Maxim. It monitors your supply voltage (Vcc) and generates a reset signal to a microcontroller or digital IC to ensure proper startup and operation.
Key points
- Threshold variants: available in several Vtrip options (e.g., around 2.93V, 3.08V, 3.46V, 4.63V) to match your supply rail.
- Reset behavior: RESET asserts (active-low) when Vcc is below the selected threshold or when a manual reset is applied; it releases after Vcc stabilizes and the on-chip POR delay elapses.
- Easy interface: only need Vcc, GND, and the RESET line; optional manual reset input is often provided.
- Packaging: LEUR+T indicates RoHS-compliant, lead-free packaging with extended temperature range, in Tape & Reel.
Typical use
- Provide reliable MCU/bus reset during power-up/power-down or brown-out conditions.
For exact pinout, thresholds, and timing, see the MAX809 datasheet and the specific variant markings.

Equivalent products to MAX809LEUR+T (voltage supervisor/reset) include:
- ON Semiconductor CAT809/CAT810
- TI TPS3800/TPS389x families
- Analog Devices ADM803/ADM809
- Microchip MCP131/MCP132 family
All are fixed-threshold/reset supervisory ICs in small packages with active-low reset outputs for 2.5–3.3 V rails. For exact threshold matching (2.63 V, 2.93 V, 3.08 V, etc.), select the corresponding variant within each family.

Key features of MAX809LEUR+T (a fixed-threshold voltage supervisor):
- Fixed-threshold voltage detector: options include standard thresholds such as 2.63 V, 2.93 V, and 4.63 V (variant dependent).
- Reset output: active-low reset. Outputs a clean reset signal when Vcc drops below the threshold or during power-up until Vcc stabilizes.
- No external components required: simple, ready-to-use supervision with a built-in reset timeout.
- Very low quiescent current: designed for minimal power drain in normal operation.
- Fast fault response: detects supply drops quickly to ensure MCU/MPU safety.
- Wide supply range and temperature tolerance: suitable for typical 2.7–5.5 V systems and industrial temperature ranges (industrial to automotive variants are available in related parts).
- Packaging: LEUR indicates lead-free, tape-and-reel packaging (RoHS-compliant).
Note: Exact threshold, output type (push-pull vs. open-drain), and temperature range depend on the specific sub-variant of MAX809 you choose.

- Pin count: 8 pins (8-pin package)
- Function: Microprocessor supervisory/reset IC. Monitors Vcc and generates a reset signal for a microcontroller (provides power-on/brown-out reset and proper reset release). Typically outputs an active-low reset.

- Manufacturer: Maxim Integrated Products, Inc. (now part of Analog Devices).
- What kind of company: A global semiconductor company that designs and markets analog and mixed-signal integrated circuits.

MAX809LEUR+T is a voltage supervisor that provides a reset signal to a microcontroller or other digital IC when Vcc falls below its threshold and releases reset when Vcc is stable. Applications: power-on reset and brown-out protection for MCUs/FPGA/DSP, safe startup/shutdown sequencing in embedded systems, consumer electronics, automotive and industrial equipment, and battery-powered devices on 3.3V/5V rails. Packaging notes: Pb-free (lead-free) in SOT-23 with Tape & Reel (LEUR+T).

SC-70-3 (SOT-23-3) small leadless package. +T indicates Tape & Reel.