Document
New Features Repetitive Alarms & Temperature Compensation
®
2-Wire™ RTC, 256K (32K x 8)
Intersil Real Time Clock/Calendar/CPU Supervisor with EEPROM
FEATURES
• Real Time Clock/Calendar — Tracks time in Hours, Minutes, Seconds and Hundredths of a Second — 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 • Battery Switch or Super Cap Input • 32K x 8 Bits of EEPROM — 128-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 • Frequency Output (SW Selectable: Off, 1Hz, 100Hz, or 32.768kHz) • Low Power CMOS — 1.25µA Operating Current (Typical) • Small Package Options — 8-Lead EIAJ SOIC and 14-Lead TSSOP
X1286
APPLICATIONS
• • • • • • • • • • • • • • • 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
BLOCK DIAGRAM
OSC Compensation
X1
32.768kHz
X2
Oscillator
Frequency Divider
1Hz
Timer Calendar Logic
Time Keeping Registers (SRAM)
Battery Switch Circuitry
VCC VBACK
PHZ/IRQ
Select Status Registers (SRAM) Mask
SCL SDA
Serial Interface Decoder
Control Decode Logic
Control/ Registers (EEPROM)
Alarm
Compare Alarm Regs (EEPROM) 256K EEPROM ARRAY
8
*I2C is a Trademark of Philips. REV 1.1 7/8/04
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X1286
PIN DESCRIPTIONS
8-pin EIAJ SOIC X1 X2 PHZ/IRQ VSS 1 2 3 4 8 7 6 5 VCC VBACK SCL SDA X1 X2 NC NC NC PHZ/IRQ VSS
14- pin TSSOP 1 2 3 4 5 6 7 14 13 12 11 10 9 8 VCC VBACK NC NC NC SCL SDA
ORDERING INFORMATION VCC Range
2.7–5.5V
Package
8L EIAJ SOIC 14L TSSOP
Operating Temperature Range
0–70°C -40–85°C 0–70°C -40–85°C
Part Number
X1286A8 X1286A8I X1286V14 X1286V14I
PART MARK INFORMATION 14-Lead TSSOP EYWW XXXXX 1286 = 2.7 to 5.5V, 0 to +70°C 1286I = 2.7 to 5.5V, -40 to +85°C 8-Lead EIAJ SOIC X1286 EYWWX Blank = 2.7 to 5.5V, 0 to +70°C I = 2.7 to 5.5V, -40 to +85°C
REV 1.1 7/8/04
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X1286
PIN ASSIGNMENTS Pin Number EIAJ SOIC
1
TSSOP
1
Symbol
X1
Brief Description
X1. The X1 pin is the input of an inverting amplifier. An external 32.768kHz quartz crystal is used with the X1286 to supply a timebase for the real time clock. The recommended crystal is a Citizen CFS206-32.768KDZF. Internal compensation circuitry is included to form a complete oscillator circuit. Care should be taken in the placement of the crystal and the layout of the circuit. Plenty of ground plane around the device and short traces to X1 are highly recommended. See Application section for more recommendations. X2. The X2 pin is the output of an inverting amplifier. An external 32.768kHz quartz crystal is used with the X1286 to supply a timebase for the real time clock. The recommended crystal is a Citizen CFS206-32.768KDZF. Internal compensation circuitry is included to form a complete oscillator circuit. Care should be taken in the placement of the crystal and the layout of the circuit. Plenty of ground plane around the device and short traces to X2 are highly recommended. See Application section for more recommendations. Programmable Frequency/Interrupt Output – PHZ/IRQ. This is either an output from the internal oscillator or an interrupt signal output. It is a CMOS output. When used as frequency output, this signal has a frequency of 32.768kHz, 100Hz, 1Hz or inactive. When used as interrupt output, this signal notifies a host processor that an alarm has occurred and an action is required. It is an active LOW output. The control bits for this function are FO1 and FO0 and are found in address 0011h of the Clock Control Memory map. See “Programmable Frequency Output Bits—FO1, FO0” on page 13. VSS. Serial Data (SDA). SDA is a bidirectional pin used to transfer data into and out of the device. It has an open drain output and may be wire ORed with other open drain or open collector outputs. The input buffer is always active (not gated). An open drain output requires the use of a pull-up resistor. The output circuitry controls the fall time of the output signal with the use of a slope controlled pulldown. The circuit is designed for 400kHz 2-wire interface speed. Serial Clock (SCL). The SCL input is used to clock all data into and out of the device. The input buffer on this pin is always active (not gated). VBACK. This input provides a backup supply voltage to the device. VBACK sup.