Analog Devices Inc./Maxim Integrated DS1819CR-10+T&R

Overview

DS1819CR-10+T&R from Maxim Integrated is a 3.3V microprocessor supervisory circuit in SOT-23-5 package, featuring 10% VCC trip point (2.85–3.00 V), 140 ms minimum reset pulse width, watchdog timeout of 1.12 s, pushbutton reset input, and industrial temperature range (−40°C to +85°C). It halts and restarts out-of-control microprocessors during power transients or software hangs in embedded control systems.

For engineers reviewing the DS1819CR-10+T&R datasheet, DS1819CR-10+T&R pinout, DS1819CR-10+T&R application, or DS1819CR-10+T&R equivalent, key selection criteria include VCC trip accuracy, reset timing stability, watchdog strobe compatibility, pushbutton debounce behavior, and SOT-23-5 footprint constraints in space-constrained microcontroller power management designs.

Technical Context

The DS1819CR-10+T&R implements a precision voltage monitor with 5 mV hysteresis, a 1.12 s watchdog timer triggered by ST input transitions, and a debounced PBRST input that generates a guaranteed 140 ms active-low reset pulse on button release. Its push-pull RST output remains valid down to 1.0 V VCC and supports 0 V operation with external pull-down.

This variant belongs to the DS1819 'C' family subtype: Pin 1 = RST (active-low), Pin 2 = GND, Pin 3 = RST (active-high), Pin 4 = PBRST (active-low), Pin 5 = VCC. It integrates power-on reset, power-fail detection, watchdog supervision, and manual reset - all in a single 5-pin SOT-23-5 IC without external components.

Key Specifications

Pinout & Package

SOT-23-5 surface-mount package: 2.9 mm × 1.6 mm × 1.1 mm body, gull-wing leads, JEDEC MO-178AC compliant.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX823SEUK+T and TPS3808G12DBVR, DS1819CR-10+T&R uniquely combines 3.0 V operation, dual active-high/low reset outputs, integrated pushbutton debounce, and hardware watchdog in one SOT-23-5 package-reducing board area and eliminating four discrete components in compact embedded controllers.

Availability

DS1819CR-10+T&R is available at Aetrix Electronics and suitable for industrial PLC controllers, medical infusion pumps, smart energy meters, and automotive body control modules requiring stable component supply, long-term lifecycle support, and consistent parametric performance across temperature and voltage variation.

Supply support for DS1819CR-10+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

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

The DS1819 series targets microprocessor supervisory functions in 3.0 V embedded systems-delivering integrated power monitoring, watchdog timing, and manual reset in minimal footprint for space- and reliability-critical designs.

FAQ

What is the exact VCC trip voltage range for DS1819CR-10+T&R?

The DS1819CR-10+T&R has a guaranteed VCC trip point of 2.85 V to 3.00 V at 25°C, corresponding to its 10% tolerance rating for 3.0 V systems. This range is specified across the full −40°C to +85°C operating temperature and accounts for hysteresis of 5 mV. The trip point remains stable over time and voltage slew rates up to 12.5 V/s, ensuring robust brownout detection in noisy power environments.

How does the watchdog timer in DS1819CR-10+T&R operate, and can it be disabled?

The DS1819CR-10+T&R watchdog timer times out after 1.12 seconds if the ST input does not transition. Upon timeout, it asserts both RST outputs for 140 ms. The watchdog is disabled by leaving the ST pin unconnected (floating) or tri-stated-no external pull-up/down is required. This behavior is confirmed in the device's functional description and timing diagrams, and applies specifically to DS1819 'A' and 'B' variants; DS1819CR-10+T&R is a 'C' variant and retains full watchdog functionality.

Does DS1819CR-10+T&R support both active-low and active-high reset outputs simultaneously?

Yes, DS1819CR-10+T&R provides two independent reset outputs: Pin 1 (RST) is active-low and Pin 3 (RST) is active-high. Both assert synchronously during power failure, watchdog timeout, or PBRST activation. This dual-output architecture eliminates the need for external inverters or level shifters when interfacing with microcontrollers requiring either reset polarity-confirmed by the pin assignment table and block diagram in the official datasheet.

What is the function of Pin 4 (PBRST) on DS1819CR-10+T&R, and how is it debounced?

Pin 4 (PBRST) is an active-low pushbutton reset input that triggers a 140 ms minimum reset pulse upon release-not press-of the connected switch. Internal circuitry provides 1 µs noise immunity: pulses shorter than 100 ns are ignored. Debouncing is fully hardware-based; no external RC network or firmware polling is required. This behavior is specific to DS1819 'A' and 'C' variants, and DS1819CR-10+T&R is a 'C' variant, confirming PBRST functionality per datasheet Figures 2 and 3.

Can DS1819CR-10+T&R operate down to 0 V VCC, and how is output validity maintained?

DS1819CR-10+T&R's RST output remains logic-valid down to 1.0 V VCC using its internal push-pull driver. To extend validity to 0 V, a 100 kΩ resistor from RST to GND is recommended-this pulls the output low when VCC collapses, ensuring a defined reset state throughout full power-down. This technique is explicitly described in the "OUTPUT VALID CONDITIONS" section and validated in Figure 9 of the datasheet, applying directly to DS1819CR-10+T&R's RST pin.