DS1688/DS1691 DS1287 DS1688 DS1688S DS1691 DS1285 DS1385 DS1485 DS1585 - Datasheet Archive

 

DS1688/DS1691 3 Volt/5 Volt Serialized Real Time Clock with NV RAM Control FEATURES PIN ASSIGNMENT Incorporates industry standard

 

DS1688/DS1691 DS1688/DS1691 DS1688/DS1691 DS1688/DS1691 3 Volt/5 Volt Serialized Real Time Clock with NV RAM Control FEATURES PIN ASSIGNMENT Incorporates industry standard DS1287 DS1287 PC clock plus enhanced features: VBAUX 1 28 CEI VBAUX 1 28 CEI X1 2 27 CEO X1 2 27 CEO X2 3 26 VCCI X2 3 26 VCCI RCLR 4 25 VCCO RCLR 4 25 VCCO AD0 5 24 SQW AD0 5 24 SQW AD1 6 23 VBAT AD1 6 23 VBAT AD2 7 22 IRQ AD2 7 22 IRQ AD3 8 21 PSEL AD3 8 21 PSEL AD4 9 20 RD AD4 9 20 RD AD5 10 19 GND AD5 10 19 GND AD6 11 18 WR AD6 11 18 WR AD7 12 17 ALE AD7 12 17 ALE PWR 13 16 CS PWR 13 16 CS GND 14 15 KS GND 14 15 KS · +3 or +5 volt operation · 64­bit Silicon serial number · 64­bit customer specific ROM or additional serial number available · Power control circuitry supports system power on from date/time alarm or key closure · Automatic battery backup and write protection to external SRAM · Crystal select bit allows RTC to operate with 6 pF or DS1688 DS1688 28­PIN DIP (600 MIL) DS1688S DS1688S 28­PIN SOIC (330 MIL) 12.5 pF crystal VBAUX 1 28 CEI NC 2 27 CEO NC 3 26 VCCI RCLR 4 25 · RAM clear input VCCO AD0 5 24 SQW · Century register AD1 6 23 NC AD2 7 22 IRQ · 32 KHz output for power management AD3 8 21 PSEL AD4 9 20 RD · 32­bit VCC powered elapsed time counter AD5 10 19 NC · 32­bit VBAT powered elapsed time counter AD6 11 18 WR AD7 12 17 ALE PWR 13 16 CS GND 14 15 KS · 114 bytes user NVRAM · Auxiliary battery input · 16­bit power cycle counter · Compatible with existing BIOS for original DS1287 DS1287 DS1691 DS1691 28­PIN ENCAPSULATED PACKAGE (740 MIL) functions · Available as chip (DS1688 DS1688) or stand­alone module with embedded battery and crystal (DS1691 DS1691) · Timekeeping algorithm includes leap year compensation valid up to 2100 ORDERING INFORMATION PART # DS1688 DS1688 DS1688S DS1688S DS1691 DS1691 DESCRIPTION RTC Chip, 28­pin DIP RTC Chip, 28­pin SOIC RTC Module; 28­pin DIP ECopyright 1995 by Dallas Semiconductor Corporation. All Rights Reserved. For important information regarding patents and other intellectual property rights, please refer to Dallas Semiconductor data books. PIN DESCRIPTION X1 X2 RCLR AD0-AD7 PWR KS CS ALE WR RD VCCO ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ Crystal Input Crystal Output RAM Clear Input Mux'ed Address/Data Bus Power­on Interrupt Output Kickstart Input RTC Chip Select Input RTC Address Strobe RTC Write Data Strobe RTC Read Data Strobe RAM Power Supply Output 041697 1/5 DS1688/DS1691 DS1688/DS1691 IRQ SQW VCCI GND VBAT VBAUX PSEL CEI CEO ­ ­ ­ ­ ­ ­ ­ ­ ­ Interrupt Request Output Square Wave Output +3 or +5 Volt Main Supply Ground Battery + Supply Auxiliary Battery Supply +3 or +5 Volt Power Select RAM Chip Enable In RAM Chip Enable Out DESCRIPTION The DS1688/DS1691 DS1688/DS1691 is a real time clock (RTC) designed as a successor to the industry standard DS1285 DS1285, DS1385 DS1385, DS1485 DS1485, and DS1585 DS1585 PC real time clocks. This device provides the industry standard DS1285 DS1285 clock function with the new feature of either +3.0 or +5.0 volt operation and automatic backup and write protection to an external SRAM. The DS1688 DS1688 also incorporates a number of enhanced features including a silicon serial number, power on/off control circuitry, 114 bytes of user NVSRAM, power on elapsed timer, and power cycle counter. Each DS1688/DS1691 DS1688/DS1691 is individually manufactured with a unique 64­bit serial number as well as an additional 64­bit customer specific ROM or serial number. The serial number is programmed and tested at Dallas to insure that no two devices are alike. The serial number can be used to electronically identify a system for purposes such as establishment of a network node address or for maintenance tracking. Blocks of available numbers from Dallas Semiconductor can be reserved by the customer. The serialized RTC's also incorporate power control circuitry which allows the system to be powered on via an external stimulus, such as a keyboard or by a time and date (wake up) alarm. The PWR output pin can be triggered by one or either of these events, and can be used to turn on an external power supply. The PWR pin is under software control, so that when a task is complete, the system power can then be shut down. 041697 2/5 The DS1688/DS1691 DS1688/DS1691 incorporates a power on elapsed time counter, a power on cycle counter, and a battery powered continuous counter. These three counters provide valuable information for maintenance and warranty requirements. Automatic backup and write protection for an external SRAM is provided through the VCCO and CEO pins. The lithium energy source used to permanently power the real time clock is also used to retain RAM data in the absence of VCC power through the VCCO pin. The chip enable output to RAM (CEO) is controlled during power transients to prevent data corruption. The DS1688 DS1688 is a clock/calendar chip with the features described above. An external crystal and battery are the only components required to maintain time­of­day and memory status in the absence of power. The DS1691 DS1691 incorporates the DS1688 DS1688 chip, a 32.768 KHz crystal, and a lithium battery in a complete, self­contained timekeeping module. The entire unit is fully tested at Dallas Semiconductor such that a minimum of 10 years of timekeeping and data retention in the absence of VCC is guaranteed. For a complete description of operating conditions, electrical characteristics, bus timing, and pin descriptions other than the SQW output, see the DS1689/DS1693 DS1689/DS1693 data sheet. SIGNAL DESCRIPTION SQW (Square Wave Output) ­ The SQW output signal functions identical to the DS1689/DS1693 DS1689/DS1693 with an exception occurring at power­up. A 32 KHz square wave will be output on this pin, tREC, after a power­up condition has been detected. This condition sets the following bits enabling the 32 KHz output; DV1=1, SQWE=1, and E32K=1. The square wave will be output on this pin if either SQWE=1 or E32K=1. DS1688/DS1691 DS1688/DS1691 DS1688 DS1688 28­PIN DIP PKG 28­PIN DIM MIN MAX A IN. MM 1.445 36.70 1.470 37.34 B IN. MM 0.530 13.46 0.550 13.97 C IN. MM 0.140 3.56 0.160 4.06 D IN. MM 0.600 15.24 0.625 15.88 E IN. MM 0.015 0.38 0.040 1.02 F IN. MM 0.120 3.05 0.145 3.68 C G IN. MM 0.090 2.29 0.110 2.79 F H IN. MM 0.625 15.88 0.675 17.15 J IN. MM 0.008 0.20 0.012 0.30 K IN. MM 0.015 0.38 0.022 0.56 B D 1 A K G E J H 041697 3/5 DS1688/DS1691 DS1688/DS1691 DS1688S DS1688S 28­PIN SOIC K G PKG 28­PIN DIM MIN MAX A IN. MM 0.706 17.93 0.728 18.49 B IN. MM 0.338 8.58 0.350 8.89 C IN. MM 0.086 2.18 0.110 2.79 D IN. MM 0.020 0.58 0.050 1.27 E IN. MM 0.002 0.05 0.014 0.36 F IN. MM 0.090 2.29 0.124 3.15 G IN. MM 0.050 1.27 H IN. MM 0.460 11.68 0.480 12.19 J IN. MM 0.006 0.15 0.013 0.33 K IN. MM 0.014 0.36 0.020 0.51 BSC C A E B F 0­8 deg. typ. J H D 041697 4/5 DS1688/DS1691 DS1688/DS1691 DS1691 DS1691 28­PIN 740 MIL MODULE 15 28 PKG 28­PIN DIM D K 0.130 3.30 0.015 0.38 0.030 0.76 IN. MM 0.110 2.79 0.140 3.56 0.090 2.29 0.110 2.79 H IN. MM 0.590 14.99 0.630 16.00 IN. MM 0.008 0.20 0.012 0.30 K IN. MM NOTE: 0.100 2.54 J 13 EQUAL SPACES AT .100 ± .010 TNA 0.375 9.52 G IN. MM G 0.350 8.89 F F 0.740 18.80 E IN. MM E 0.695 17.65 D IN. MM C 1.540 39.12 C IN. MM 14 1.520 38.61 B IN. MM A MAX A IN. MM 1 MIN 0.015 0.38 0.021 0.53 PINS 2, 3, 19 AND 23 ARE MISSING BY DESIGN. J H B 041697 5/5