Analog Devices Inc./Maxim Integrated DS1817-20+

Overview

DS1817-20+ from Maxim Integrated (now Analog Devices) is a precision voltage-monitoring supervisory IC that provides active-high reset signaling for microprocessors in 3.0V systems. It features a 20% V_CC trip point (2.47–2.64V), 150ms reset pulse width, push-pull output, and operates from -40°C to +85°C in SOT-23 or TO-92 packages.

For engineers reviewing the DS1817-20+ datasheet, DS1817-20+ pinout, DS1817-20+ application, or DS1817-20+ equivalent, key selection criteria include trip-point tolerance matching for 3.0V rails, guaranteed 150ms reset hold time after power recovery, push-pull output drive capability (350µA high, 10mA low), and compatibility with space-constrained PCB layouts using the SOT-23-3 package.

Technical Context

The DS1817-20+ integrates a temperature-compensated voltage reference and comparator to detect V_CC deviations beyond ±20% of nominal 3.0V. Its internal circuitry asserts RST immediately on undervoltage detection and holds it active for 100–250ms (typ. 150ms) after V_CC returns within tolerance.

It uses a CMOS push-pull output stage capable of sourcing 350µA at V_CC – 0.5V and sinking 10mA at 0.4V, eliminating external pull-up resistors. The device draws only 28–35µA quiescent current and supports V_CC from 1.2V to 5.5V, enabling use across multiple supply domains.

Key Specifications

Pinout & Package

DS1817-20+ is available in SOT-23-3 (surface-mount) and TO-92 (through-hole) packages. Both share identical pinout: Pin 1 = RST (active-high reset output), Pin 2 = V_CC (power supply input), Pin 3 = GND (ground).

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS3808G12DBVR and MAX6326UT29D3+T, DS1817-20+ delivers plug-and-play 3.0V/20% supervision with push-pull output-reducing design effort and component count-while maintaining industrial temperature range and proven reliability in long-lifecycle embedded systems.

Availability

DS1817-20+ is available at Aetrix Electronics and suitable for industrial control, smart metering, automotive body electronics, and IoT edge node designs requiring stable component supply and long-term manufacturability.

Supply support for DS1817-20+ 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

Analog Devices (via acquisition of Maxim Integrated) designs precision analog, mixed-signal, and power management ICs for industrial, automotive, and communications applications.

The DS1817-20+ belongs to Maxim's EconoReset™ family of supervisory circuits, engineered to replace discrete reset solutions in cost-sensitive, space-constrained microprocessor systems with reliable, single-chip power monitoring.

FAQ

What is the exact V_CC trip point range for DS1817-20+?

The DS1817-20+ has a guaranteed V_CC trip point range of 2.47V to 2.64V at +25°C, corresponding to ±20% of a nominal 3.0V supply. This range is maintained across the full -40°C to +85°C operating temperature with built-in temperature compensation, ensuring consistent undervoltage detection without external calibration. DS1817-20+ does not require trimming or adjustment.

Does DS1817-20+ require an external pull-up resistor on the RST pin?

No, DS1817-20+ features a push-pull output stage that actively drives RST high and low, eliminating the need for an external pull-up resistor. This simplifies schematic design, reduces BOM count, and avoids potential timing delays or noise susceptibility associated with passive pull-ups. DS1817-20+ can directly interface with standard CMOS/TTL reset inputs.

Can DS1817-20+ operate with supply voltages below 3.0V?

Yes, DS1817-20+ supports V_CC from 1.2V to 5.5V per its recommended operating conditions. However, its internal 20%-tolerance threshold is calibrated for nominal 3.0V systems - meaning the trip point remains fixed at ~2.55V regardless of actual V_CC. It will assert reset if V_CC falls below 2.47V, even when powered from 2.8V or 3.3V rails, making it suitable for flexible supply monitoring.

What is the reset timeout behavior of DS1817-20+ during power-up?

Upon power-up, DS1817-20+ holds RST active for 100–250ms (typ. 150ms) after V_CC rises above the trip threshold (2.47–2.64V). This ensures sufficient time for both the power supply and connected microprocessor to stabilize before releasing reset. The timing is internally generated and independent of external capacitors or resistors, guaranteeing consistent behavior across units and temperatures. DS1817-20+ provides this delay without external components.

Is DS1817-20+ pin-compatible with other DS1817 variants like DS1817-10+?

Yes, all DS1817 variants-including DS1817-5+, DS1817-10+, and DS1817-20+-share identical pinout, package dimensions, and electrical interface. The only difference is the factory-trimmed V_CC trip point: 2.98–3.15V (5%), 2.80–2.97V (10%), or 2.47–2.64V (20%). This allows direct substitution based on system voltage tolerance requirements without PCB or firmware changes. DS1817-20+ maintains full mechanical and functional compatibility within the family.