DS1689 Datasheet, PDF (1/32 Pages) Dallas Semiconductor – 3-Volt/5-Volt Serialized Real-Time Clock with NV RAM Control

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DS1689/DS1693
3-Volt/5-Volt Serialized Real-Time Clock
with NV RAM Control
FEATURES
Incorporates industry standard DS1287 PC clock
plus enhanced features:
§ +3- or +5V operation
§ 64-bit silicon serial number
§ 64-bit 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 12.5 pF crystal
§ 114 bytes user NV RAM
§ Auxiliary battery input
§ RAM clear input
§ Century register
§ 32 kHz output for power management
§ 32-bit V_CC powered elapsed time counter
§ 32-bit V_BAT powered elapsed time counter
§ 16-bit power cycle counter
§ Compatible with existing BIOS for original
DS1287 functions
§ Available as IC (DS1689) or standalone
module with embedded battery and crystal
(DS1693)
§ IC is available in industrial temperature
version
§ Timekeeping algorithm includes leap year
compensation valid up to 2100
ORDERING INFORMATION
PART #
DS1689S
DS1689SN
DS1693
DESCRIPTION
RTC IC, 28-pin SOIC
RTC IC, 28-pin SOIC IND
RTC Module; 28-pin DIP
PIN ASSIGNMENT
VBAUX 1
NC 2
NC 3
RCLR ⁴
AD0 5
AD1 ⁶
AD2 7
AD3 ⁸
AD4 9
AD5 ¹⁰
AD6 11
AD7 ¹²
PWR ¹³
GND ¹⁴
28 _CEI
27 _CEO
26 VCCI
25 VCCO
24 SQW
23 NC
22 _IRQ
21 _PSEL
20 _RD
19 _NC
18 _WR
17 _ALE
16 _CS
15 _KS
VBAUX
1
X1 2
X2 3
RCLR ⁴
AD0 5
AD1 ⁶
AD2 ⁷
AD3 8
AD4 9
AD5 10
AD6 11
AD7 ¹²
PWR ¹³
GND ¹⁴
28 _CEI
27 _CEO
26 _VCCI
25 _VCCO
24 _SQW
23 _VBAT
22 _IRQ
21 _PSEL
20 _RD
19 _GND
18 WR
17 _ALE
16 _CS
15 _KS
DS1693 28-Pin Encapsulated Package _{DS1689S 28-Pin SOIC}
(740-mil)
(330-mil)
PIN DESCRIPTION
X1
- Crystal Input
X2
- Crystal Output
RCLR
- RAM Clear Input
AD0-AD7 - Mux’ed Address/Data Bus
PWR
- Power-on Interrupt Output
(Open drain)
KS
- Kickstart Input
CS
- RTC Chip Select Input
ALE
- RTC Address Strobe
WR
- RTC Write Data Strobe
RD
V_CCO
- RTC Read Data Strobe
- RAM Power Supply Output
IRQ
SQW
V_CCI
GND
V_BAT
V_BAUX
PSEL
- Interrupt Request Output
(Open drain)
- Square Wave Output
- +3- or +5V Main Supply
- Ground
- Battery + Supply
- Auxiliary Battery Supply
- +3- or +5V Power Select
CEI
- RAM Chip Enable In
CEO
- RAM Chip Enable Out
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