Analog Devices Inc./Maxim Integrated DS1815R-5/T&R

Overview

DS1815R-5/T&R from Maxim Integrated (now Analog Devices) is a precision 3.3V microprocessor supervisory circuit with push-pull active-low reset output, 150ms reset timeout, and ±5% VCC trip point accuracy (2.98V–3.15V). It monitors power supply integrity and automatically asserts reset during brownout or power-up until stabilization, used in embedded controllers and industrial microcontroller systems.

For engineers reviewing the DS1815R-5/T&R datasheet, DS1815R-5/T&R pinout, DS1815R-5/T&R application, or DS1815R-5/T&R equivalent, key selection criteria include guaranteed 150ms reset pulse width, push-pull output capable of sourcing 350µA at 2.4V, operation down to 0V VCC, and SOT-23-3 package compatibility with TO-92 footprint alternatives.

Technical Context

The DS1815R-5/T&R integrates a temperature-compensated voltage reference and comparator to detect VCC deviations beyond ±5% of nominal 3.3V. Its internal timing circuit ensures RST remains asserted for 100–250ms after VCC returns to tolerance, with typical 150ms duration.

It features a CMOS push-pull output stage that drives low without external pull-up, supports VCC operation from 1.2V to 5.5V, and maintains valid reset assertion even as VCC drops to 0V - critical for fail-safe power-down sequencing in battery-backed or low-power systems.

Key Specifications

Pinout & Package

SOT-23-3 surface-mount package (3.0mm × 1.7mm × 1.3mm), compatible with TO-92 through-hole footprint variants; RoHS-compliant, lead-free finish.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar microprocessor supervisory applications.

Compared with MAX6326–33D and TPS3808G33DBVR, the DS1815R-5/T&R delivers fixed 150ms reset timing with zero external components, push-pull output, and guaranteed reset assertion through full VCC collapse - making it optimal for cost-sensitive, space-constrained industrial and metering designs where simplicity and fail-safe behavior are prioritized.

Availability

DS1815R-5/T&R is available at Aetrix Electronics and suitable for industrial control panels, smart utility meters, medical handheld diagnostics, and IoT edge nodes requiring stable component supply and long-term production continuity.

Supply support for DS1815R-5/T&R includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Analog Devices (via acquisition of Maxim Integrated) is a global leader in high-performance analog, mixed-signal, and digital signal processing technologies, serving industrial, automotive, communications, and healthcare markets.

The DS1815R-5/T&R belongs to Maxim's EconoReset™ family of supervisory circuits, designed specifically for cost-effective, single-chip power monitoring and reset generation in resource-constrained embedded systems.

FAQ

What is the exact VCC trip voltage range for DS1815R-5/T&R?

The DS1815R-5/T&R has a guaranteed VCC trip point range of 2.98V to 3.15V at +25°C, corresponding to ±5% tolerance around 3.3V nominal. This specification is validated across the full operating temperature range (-40°C to +85°C) and ensures consistent brownout detection in 3.3V systems without external adjustment. The DS1815R-5/T&R uses an on-chip temperature-compensated reference to maintain this accuracy.

Does DS1815R-5/T&R require an external pull-up resistor on the RST pin?

No, the DS1815R-5/T&R features a push-pull output stage that actively drives both high and low states, eliminating the need for an external pull-up resistor. This reduces BOM count and PCB area while improving noise immunity compared to open-drain alternatives. The DS1815R-5/T&R can source up to 350µA at 2.4V and sink up to 10mA at 0.4V, ensuring robust interfacing with standard microcontroller reset inputs.

How long does the DS1815R-5/T&R hold reset active after VCC returns to tolerance?

The DS1815R-5/T&R holds the RST pin active (low) for 100ms to 250ms after VCC rises above its trip threshold, with a typical duration of 150ms. This timing is internally generated and does not require external capacitors or resistors. The DS1815R-5/T&R ensures this delay is maintained across temperature and supply variations, meeting JEDEC JESD78 requirements for microprocessor initialization reliability.

Can DS1815R-5/T&R operate with VCC below 3.3V, such as during battery discharge?

Yes, the DS1815R-5/T&R operates over a VCC range of 1.2V to 5.5V and continues asserting reset even as VCC falls to 0V - a key feature for fail-safe shutdown. Its internal reference and comparator remain functional down to 1.2V, and the DS1815R-5/T&R guarantees valid reset output throughout full power collapse, preventing unintended MCU operation during brownout or battery depletion.

Is DS1815R-5/T&R pin-compatible with other SOT-23-3 reset supervisors?

The DS1815R-5/T&R uses standard SOT-23-3 pinout (Pin 1 = RST, Pin 2 = VCC, Pin 3 = GND), matching industry conventions for 3-pin reset ICs. However, it is not a drop-in replacement for open-drain devices like the MAX6326 series due to its push-pull output behavior. Always verify reset polarity, timing, and drive strength when substituting. The DS1815R-5/T&R's pinout is identical across TO-92 and SOT-23 packages.