DS1677 便携系统控制器

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概述

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The DS1677 portable system controller is a circuit that incorporates many of the functions necessary for low-power portable products integrated into one chip. The device provides a real-time clock (RTC), NV RAM controller, microprocessor monitor, power-fail warning, and a 3-channel, 8-bit analog-to-digital converter (ADC). Communication with the DS1677 is established through a simple 3-wire interface.

The RTC provides seconds, minutes, hours, day, date, month, and year information with leap year compensation. The RTC also provides an alarm interrupt. This interrupt works when the DS1677 is powered by the system power supply or when in battery-backup operation so the alarm can be used to wake up a system that is powered down.

Automatic backup and write protection of an external SRAM is provided through the V_CCO and active-low CEO pins. The backup energy source used to power the RTC is also used to retain RAM data in the absence of V_CC through the V_CCO pin. Active-low CEO, the chip-enable output to SRAM, is controlled during power transients to prevent data corruption.

关键特性

Provides Real-Time Clock
- Counts Seconds, Minutes, Hours, Date of the
- Month, Month, Day of the Week, and Year
- with Leap Year Compensation Valid Up to 2100
- Power Control Circuitry Supports System
- Power-On from Day/Time Alarm
Microprocessor Monitor
- Halts Microprocessor During Power-Fail
- Automatically Restarts Microprocessor After
- Power Failure
- Monitors Pushbutton for External Override
- Halts and Resets an Out-of-Control Microprocessor
NV RAM Control
- Automatic Battery Backup and Write
- Protection to External SRAM
3-Channel, 8-Bit ADC
Simple 3-Wire Interface
+5.0V Operation
1.25V Threshold Detector for Power-Fail Warning
UL Recognized

Key Specifications: Timekeeping & Real-Time Clocks

Part Number

Functions

Time Format (hh = sec/100)

Date Format

Interface

Supply Voltage (V)

Time- keeping Current (typ) (nA)

C_L, Load Capacitance (pF)

Memory Type

Number of Time of Day Alarms

Features

RoHS Available

Package

Smallest Available Package (max w/pins) (mm²)

Operating Temp. Range (°C)

Price^**

DS1677

•	NV SRAM Control

•	Watchdog Timekeeper

HH:MM:SS

YY-MM-DD

3-Wire

300

None

•

µP Reset

•	A to D Converter

•	Periodic Interrupt

•	Power Fail Output

Yes

TSSOP/20

0 to +70

$3.44 @ 1k

See All Timekeeping & Real-Time Clocks (86)

Notes:
^**This pricing is BUDGETARY, for comparing similar parts. Prices are in U.S. dollars and subject to change. Quantity pricing may vary substantially and international prices may differ due to local duties, taxes, fees, and exchange rates. For volume-specific prices and delivery, please see the price and availability page or contact an authorized distributor.