Analog Devices Inc./Maxim Integrated DS1815-20

Overview

DS1815-20 from Maxim Integrated is a precision voltage-monitoring microprocessor supervisory circuit with 20% V_CC trip point (2.47–2.64 V), 150 ms reset timeout, push-pull active-low RST output, and operation from -40°C to +85°C - used to ensure reliable power-up sequencing in embedded microcontroller systems.

For engineers reviewing the DS1815-20 datasheet, DS1815-20 pinout, DS1815-20 application, or DS1815-20 equivalent, key selection considerations include its fixed 20% undervoltage threshold, guaranteed 100–250 ms reset assertion time, TO-92/SOT-23 package compatibility, and push-pull output capable of sinking 10 mA while sourcing 350 µA.

Technical Context

The DS1815-20 integrates a temperature-compensated voltage reference and comparator to detect when V_CC falls below 2.47–2.64 V; it asserts RST low immediately upon out-of-tolerance detection and holds RST active for 100–250 ms after V_CC recovers - ensuring stable processor initialization.

Its push-pull output eliminates external pull-up resistors, supports direct interface to CMOS/TTL inputs, and operates across 1.2–5.5 V supply range while consuming only 28–35 µA quiescent current - enabling use in battery-backed and low-power embedded systems.

Key Specifications

Pinout & Package

DS1815-20 is available in both TO-92 and SOT-23 packages. Both variants share identical pin functions and terminal assignments.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar voltage-monitoring reset applications.

Compared with MAX809SEUR+T and TPS3808G12DBVR, the DS1815-20 offers fixed 20% trip tolerance optimized for cost-sensitive 3.3 V systems, guaranteed push-pull drive, and ultra-low 35 µA supply current - making it ideal where simplicity, BOM reduction, and minimal power overhead are prioritized over programmability or sub-2% trip accuracy.

Availability

DS1815-20 is available at Aetrix Electronics and suitable for microcontroller power-up sequencing, industrial sensor node supervision, and legacy 3.3 V embedded system reset requiring stable component supply and long-lifecycle support.

Supply support for DS1815-20 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

Maxim Integrated (now part of Analog Devices) designs precision analog, mixed-signal, and power management ICs for industrial, computing, and communications applications.

The DS1815-20 belongs to the EconoReset™ family - engineered for low-cost, high-reliability power-supply monitoring in resource-constrained embedded systems where predictable reset timing and minimal external components are critical.

FAQ

What is the exact V_CC trip point range for DS1815-20?

The DS1815-20 has a factory-trimmed V_CC trip point ranging from 2.47 V (minimum) to 2.64 V (maximum), corresponding to a nominal 20% undervoltage threshold relative to a 3.3 V supply. This range is specified across -40°C to +85°C and is enabled by an internal temperature-compensated voltage reference. The DS1815-20 does not support adjustment or external configuration of this threshold.

Does DS1815-20 require an external pull-up resistor on the RST pin?

No, the DS1815-20 features a push-pull RST output that actively drives both high and low states - eliminating the need for an external pull-up resistor. When asserting reset, it pulls RST to GND; when released, it drives RST to V_CC – 0.1 V (typical). This simplifies design, reduces BOM count, and improves noise immunity compared to open-drain alternatives like the MAX809 series.

How long is the reset pulse duration for DS1815-20 after V_CC returns to tolerance?

The DS1815-20 guarantees a reset pulse duration of 100–250 ms after V_CC rises above its trip threshold (2.47–2.64 V). The typical value is 150 ms, and this hold time is internally generated and independent of external capacitance. It ensures sufficient stabilization time for microprocessors, clocks, and memory subsystems before releasing the reset signal - a key requirement verified in DS1815-20's power-up timing diagram (Figure 4).

Can DS1815-20 operate with supply voltages below 3.3 V?

Yes, the DS1815-20 operates across a V_CC range of 1.2 V to 5.5 V and maintains valid reset functionality down to 1.2 V. Its internal voltage reference and comparator remain functional even as V_CC declines, allowing reliable brown-out detection in low-voltage systems such as 1.8 V or 2.5 V microcontrollers - provided the trip point (2.47–2.64 V) remains above the actual supply level.

What package options are available for DS1815-20?

The DS1815-20 is offered in two standard packages: TO-92 (through-hole) and SOT-23 (surface-mount). Both share identical pinout (RST-V_CC-GND), electrical specifications, and thermal performance. Mechanical drawings for both packages are published in Maxim's official documentation, and footprint recommendations are provided for each variant to support seamless layout integration.