Analog Devices Inc./Maxim Integrated DS1632S+T&R

Overview

DS1632S+T&R from Maxim Integrated is a PC power-fail and reset controller IC with integrated 32.768 kHz crystal oscillator, ±5% or ±10% VCC monitoring (selectable via TOL pin), 95 ms/190 ms programmable reset pulse width (via RD pin), and complementary open-drain PF/LB/RST outputs. It provides battery-backed real-time clock support for laptop/notebook chipsets.

For engineers reviewing the DS1632S+T&R datasheet, DS1632S+T&R pinout, DS1632S+T&R application, or DS1632S+T&R equivalent, key selection criteria include VCC trip point tolerance selection (4.50–4.75 V or 4.25–4.50 V), battery fail detection at 2.30–2.55 V, VCCO switched output capability up to 100 mA, and pushbutton reset debouncing with guaranteed 95/190 ms active-low pulses.

Technical Context

The DS1632S+T&R integrates three functional blocks: a low-power 32.768 kHz crystal oscillator (with rail-to-rail OSCOUT referenced to VCC or VBAT), a precision VCC comparator with selectable 5% or 10% trip thresholds (TOL pin), and a dual-mode reset generator (RD pin selects 95 ms or 190 ms pulse width). All outputs-PF, LB, RST-are open-drain with 4 mA sink capability.

Its power-switching architecture routes VCC or VBAT to VCCO and OSCOUT based on voltage hierarchy (VCC > VBAT or vice versa), with <0.3 V drop and battery current <2 µA during backup. Internal logic ensures LB remains active only while VCC is in nominal range and VBAT is below 2.30–2.55 V, and guarantees reset assertion before power-fail deactivation on power-up.

Key Specifications

Pinout & Package

DS1632S+T&R is supplied in a 16-pin SOIC (300-mil) surface-mount package, RoHS-compliant and tape-and-reel packaged (T&R).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar power-fail and reset controller applications.

Compared with MAX6900 and DS1232L, the DS1632S+T&R uniquely integrates oscillator, VCCO switching, and dual-threshold power-fail detection in one 16-pin SOIC - enabling full RTC power management without supplemental ICs or discrete pass devices.

Availability

DS1632S+T&R is available at Aetrix Electronics and suitable for laptop power management, desktop motherboard monitoring, and industrial HMI panel designs requiring stable component supply, long-term lifecycle support, and RoHS-compliant tape-and-reel packaging.

Supply support for DS1632S+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 computing, industrial, and communications applications.

The DS1632S+T&R belongs to Maxim's PC power management controller product line, engineered specifically to replace discrete reset/battery-backup circuits in x86-compatible laptops and workstations.

FAQ

What is the function of the RD pin on the DS1632S+T&R?

The RD pin on the DS1632S+T&R selects reset pulse duration: tied to GND yields 95 ms, tied to VCC yields 190 ms. It also determines power-down reset assertion delay (9 ms or 18 ms). This dual role ensures compatibility with diverse processor startup timing requirements without external timing components. The DS1632S+T&R uses this pin to guarantee minimum reset hold time after both power-up and pushbutton events.

Does the DS1632S+T&R support both 3.3 V and 5 V systems?

The DS1632S+T&R is specified for 4.5 V to 5.5 V VCC operation and requires a 5 V nominal supply; it does not operate from 3.3 V. However, its open-drain PF, LB, and RST outputs are compatible with 3.3 V logic when pulled up to 3.3 V, enabling interface to mixed-voltage systems. The DS1632S+T&R itself must be powered from 5 V to meet its VCC trip point and oscillator performance specifications.

How does the DS1632S+T&R handle battery backup during main power loss?

During main power loss, the DS1632S+T&R automatically switches VCCO and OSCOUT to VBAT (if VBAT > 2.3 V), sustaining RTC operation. All other outputs go low or high depending on VCC level to minimize battery drain. Internal battery current is <2 µA, and external loads on OSCOUT/VCCO must be added to determine total battery draw. The DS1632S+T&R ensures continuous timekeeping and low-battery warning without external MOSFETs or diodes.

Can the DS1632S+T&R drive a standard 32.768 kHz crystal without external capacitors?

The DS1632S+T&R oscillator is designed for use with 32.768 kHz crystals having 6 pF load capacitance (e.g., Daiwa DT26S or Seiko DS-VT-200). External load capacitors are not required because the oscillator circuit includes internal capacitance matching. Using a crystal outside this specification may degrade frequency accuracy or prevent oscillation. The DS1632S+T&R relies on this matched CL to achieve ±2 minutes per month RTC accuracy.

What is the purpose of the complementary PF and RST outputs on the DS1632S+T&R?

The complementary PF and RST outputs (e.g., PF and PF, RST and RST) provide differential signaling to reduce noise susceptibility and enable direct connection to latch inputs or OR-ing logic without inverters. They simplify interface to processors that require active-high or active-low reset signals simultaneously. In the DS1632S+T&R, these pairs ensure robust power-fail notification and reset assertion across varying PCB trace lengths and EMI environments.