New Features
Repetitive Alarms &
Temperature Compensation
4K (512 x 8)
X1227
APPLICATIONS
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2-Wire
™
RTC
Real Time Clock/Calendar/CPU Supervisor with EEPROM
FEATURES
• Real Time Clock/Calendar
— Tracks time in Hours, Minutes, and Seconds
— Day of the Week, Day, Month, and Year
• 2 Polled Alarms (Non-volatile)
— Settable on the Second, Minute, Hour, Day of the
Week, Day, or Month
— Repeat Mode (periodic interrupts)
• Oscillator Compensation on chip
— Internal feedback resistor and compensation
capacitors
— 64 position Digitally Controlled Trim Capacitor
— 6 digital frequency adjustment settings to ±30ppm
• CPU Supervisor Functions
— Power On Reset, Low Voltage Sense
— Watchdog Timer (SW Selectable: 0.25s, 0.75s,
1.75s, off)
• Battery Switch or Super Cap Input
• 4K x 8 Bits of EEPROM
— 64-Byte Page Write Mode
— 8 modes of Block Lock™ Protection
— Single Byte Write Capability
• High Reliability
— Data Retention: 100 years
— Endurance: 100,000 cycles per byte
• 2-Wire™ Interface interoperable with I2C*
— 400kHz data transfer rate
• Low Power CMOS
— 1.25µA Operating Current (Typical)
• Small Package Options
— 8-Lead SOIC and 8-Lead TSSOP
Utility Meters
HVAC Equipment
Audio / Video Components
Set Top Box / Television
Modems
Network Routers, Hubs, Switches, Bridges
Cellular Infrastructure Equipment
Fixed Broadband Wireless Equipment
Pagers / PDA
POS Equipment
Test Meters / Fixtures
Office Automation (Copiers, Fax)
Home Appliances
Computer Products
Other Industrial / Medical / Automotive
DESCRIPTION
The X1227 device is a Real Time Clock with clock/
calendar, two polled alarms with integrated 512x8
EEPROM, oscillator compensation, CPU Supervisor
(POR/LVS and WDT) and battery backup switch.
The oscillator uses an external, low-cost 32.768kHz
crystal. All compensation and trim components are
integrated on the chip. This eliminates several external
discrete components and a trim capacitor, saving
board area and component cost.
BLOCK DIAGRAM
OSC
Compensation
X1
Timer
Calendar
Logic
Time
Keeping
Registers
(SRAM)
Battery
Switch
Circuitry
V
CC
V
BACK
32.768kHz
X2
Oscillator
Frequency
Divider
1Hz
SCL
SDA
8
RESET
Watchdog
Timer
Low Voltage
Reset
Mask
Serial
Interface
Decoder
Control
Decode
Logic
Control/
Registers
(EEPROM)
Status
Registers
(SRAM)
Alarm
Compare
Alarm Regs
(EEPROM)
4K
EEPROM
ARRAY
*I2C is a Trademark of Philips.
REV 1.1.20 1/13/03
www.xicor.com
Characteristics subject to change without notice.
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XICOR [ XICOR INC. ]
