Analog Devices Inc./Maxim Integrated DS1236S-10+T&R

Overview

DS1236S-10+T&R from Maxim Integrated is a microprocessor supervisory IC providing power-fail detection, reset control, nonvolatile SRAM backup, watchdog timer, and early-warning NMI generation. It features 10% VCC trip point (4.37 V typical), <100 nA battery current at 25°C, and dual active-high/active-low RST outputs. Used in battery-backed embedded systems requiring orderly shutdown and memory retention during power loss.

For engineers reviewing the DS1236S-10+T&R datasheet, DS1236S-10+T&R pinout, DS1236S-10+T&R application, or DS1236S-10+T&R equivalent, key selection criteria include VCC monitoring accuracy (±0.13 V), watchdog timeout (400 ms typ), IN pin voltage threshold (2.54 V), SRAM write-protection timing (tCF = 7–44 μs), and support for both NMOS and CMOS processor modes via RC pin configuration.

Technical Context

The DS1236S-10+T&R integrates a bandgap voltage reference and precision comparator to monitor +5 V supply (VCC) with 10% tolerance (VCCTP = 4.25–4.50 V). It delivers dual reset outputs (RST active low, RST active high), non-maskable interrupt (NMI) triggered by user-defined voltage sense at IN pin (VTP = 2.5–2.6 V), and strobe-driven watchdog timer (tTD = 100–600 ms).

It implements memory backup via VCCO switching between VCC and VBAT (2.7–4.0 V), CEO-controlled SRAM write protection, and pushbutton reset debouncing (25 ms min pulse). Mode selection (NMOS vs. CMOS) is determined by RC pin level, directly affecting NMI behavior, RST assertion timing, and battery isolation strategy during power collapse.

Key Specifications

Pinout & Package

DS1236S-10+T&R is supplied in 16-pin SOIC (300-mil) package - surface-mount, RoHS-compliant, tape-and-reel format (T&R). Dimensions: 9.9 mm × 3.9 mm × 1.45 mm (L × W × H).

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX691ACPE+ and DS1233M-10+, the DS1236S-10+T&R uniquely integrates five critical functions-programmable early-warning NMI, dual-mode reset, SRAM write-protection, watchdog supervision, and battery-switched VCCO-in a single 16-pin SOIC, eliminating up to four discrete components in nonvolatile microcontroller systems.

Availability

DS1236S-10+T&R is available at Aetrix Electronics and suitable for industrial data loggers, portable medical monitors, POS terminals, smart meters, and battery-backed embedded controllers requiring stable component supply across extended product lifecycles.

Supply support for DS1236S-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) is a semiconductor company specializing in high-performance analog, mixed-signal, and power management ICs for industrial, automotive, and communications applications.

The DS1236 family was designed specifically for microprocessor-based systems needing coordinated power monitoring, reset, memory backup, and orderly shutdown - targeting battery-operated and mission-critical embedded platforms.

FAQ

What is the exact VCC trip point tolerance for DS1236S-10+T&R?

The DS1236S-10+T&R has a guaranteed 10% VCC trip point tolerance: VCCTP = 4.25 V (min) to 4.50 V (max), with 4.37 V typical at 25°C. This ensures reliable reset assertion before microprocessor operational limits are exceeded, and is factory-trimmed - not adjustable. The DS1236S-10+T&R datasheet specifies this parameter under DC Electrical Characteristics, Table "Power Sup. Trip Point".

How does DS1236S-10+T&R support both NMOS and CMOS microprocessors?

DS1236S-10+T&R supports both architectures via the RC pin: tying RC to GND configures NMOS mode (continuous RST assertion during power loss), while connecting RC to VCCO enables CMOS mode (pulsed NMI for wake-from-stop, no forced RST during VCC decay). This dual-mode capability is intrinsic to DS1236S-10+T&R's architecture and requires no external components - only RC pin routing.

Can DS1236S-10+T&R be used without an external battery?

Yes - DS1236S-10+T&R operates fully without VBAT: it monitors VCC, generates RST/NMI, manages CEO, and runs watchdog timer using only VCC. However, VBAT is required for nonvolatile SRAM backup (VCCO switching) and extended battery-backed operation. The DS1236S-10+T&R datasheet confirms functional operation down to VCC = 4.5 V even with VBAT unconnected or at 0 V.

What is the maximum load DS1236S-10+T&R can drive on VCCO?

DS1236S-10+T&R delivers up to 100 mA on VCCO when powered from VCC (VCCO = VCC − 0.3 V typical), and up to 1 mA during battery-only operation (VCCO = VBAT − 0.7 V). These values are specified in the DS1236S-10+T&R DC Electrical Characteristics table under "Supply Output Current" and define absolute safe operating limits for SRAM and peripheral power.

Does DS1236S-10+T&R include a built-in watchdog timer?

Yes - DS1236S-10+T&R includes a programmable watchdog timer with 100–600 ms timeout (400 ms typical). It is reset by a high-to-low transition on the ST pin and forces RST/RST active if unstimulated. The timer is disabled in CMOS mode by grounding IN, or in NMOS mode by leaving ST open - both methods are documented in the DS1236S-10+T&R datasheet Section "WATCHDOG TIMER".