Preliminary Information
New Features
Repetitive Alarms &
Temperature Compensation
2-Wire
™
RTC Real Time Clock/Calendar/CPU Supervisor with EEPROM
FEATURES
• Real Time Clock/Calendar
— Tracks time in Hours, Minutes, Seconds and Hun-
dredths 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 setting 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
• 32K x 8 Bits of EEPROM
— 128-Byte Page Write Mode
— 8 modes of Block Lock™ Protection
— Single Byte Write Capability
X1288
• 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
— 16-Lead SOIC and 14-Lead TSSOP
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
• High Reliability
—Data Retention: 100 years
—Endurance: 100,000 cycles per byte
BLOCK DIAGRAM
OSC
Compensation
X1
Timer
Calendar
Logic
Battery
Switch
Circuitry
32.768kHz
X2
Oscillator
Frequency
Divider
1Hz
Time
Keeping
Registers
(SRAM)
V
CC
V
BACK
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
RESET
Watchdog
Timer
Low Voltage
Reset
*I2C is a Trademark of Philips.
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Preliminary Information
PIN DESCRIPTIONS
X1288
16-pin SOIC
X1
X2
NC
NC
NC
NC
RESET
V
SS
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
14-pin TSSOP
V
CC
V
BACK
PHZ/IRQ
NC
NC
NC
SCL
SDA
NC = No internal connection
X1
X2
NC
NC
NC
RESET
V
SS
1
2
3
4
5
6
7
14
13
12
11
10
9
8
V
CC
V
BACK
PHZ/IRQ
NC
NC
SCL
SDA
ORDERING INFORMATION
V
CC
Range
4.5–5.5V
V
TRIP
Range
4.63V±112mV
Package
16L SOIC
14L TSSOP
Operating
Temperature Range
0–70°C
-40–85°C
0–70°C
-40–85°C
0–70°C
-40–85°C
0–70°C
-40–85°C
0–70°C
-40–85°C
0–70°C
-40–85°C
0–70°C
-40–85°C
0–70°C
-40–85°C
Part Number
X1288S16-4.5A
X1288S16I-4.5A
X1288V14-4.5A
X1288V14I-4.5A
X1288S16
X1288S16I
X1288V14
X1288V14I
X1288S16-2.7A
X1288S16I-2.7A
X1288V14-2.7A
X1288V14I-2.7A
X1288S16-2.7
X1288S16I-2.7
X1288V14-2.7
X1288V14I-2.7
4.5–5.5V
4.38V±112mV
16L SOIC
14L TSSOP
2.7–5.5V
2.85V±100mV
16L SOIC
14L TSSOP
2.7–5.5V
2.65V±100mV
16L SOIC
14L TSSOP
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Preliminary Information
PART MARK INFORMATION
14-Lead TSSOP
YWW
XXXXX
1288F = 2.7 to 5.5V, 0 to +70°C, V
TRIP
=2.65V±100mV
1288G = 2.7 to 5.5V, -40 to +85°C, V
TRIP
=2.65V±100mV
1288AN = 2.7 to 5.5V, 0 to +70°C, V
TRIP
=2.85V±100mV
1288AP = 2.7 to 5.5V, -40 to +85°C, V
TRIP
=2.85V±100mV
1288 = 2.7 to 5.5V, 0 to +70°C, V
TRIP
=4.38V±112mV
1288I = 2.7 to 5.5V, -40 to +85°C, V
TRIP
=4.38V±112mV
1288AL = 2.7 to 5.5V, 0 to +70°C, V
TRIP
=4.63V±112mV
1288AM = 2.7 to 5.5V, -40 to +85°C, V
TRIP
=4.63V±112mV
16-Lead SOIC
YWW
XXXXX
1288F = 2.7 to 5.5V, 0 to +70°C, V
TRIP
=2.65V±100mV
1288G = 2.7 to 5.5V, -40 to +85°C, V
TRIP
=2.65V±100mV
1288AN = 2.7 to 5.5V, 0 to +70°C, V
TRIP
=2.85V±100mV
1288AP = 2.7 to 5.5V, -40 to +85°C, V
TRIP
=2.85V±100mV
1288 = 2.7 to 5.5V, 0 to +70°C, V
TRIP
=4.38V±112mV
1288I = 2.7 to 5.5V, -40 to +85°C, V
TRIP
=4.38V±112mV
1288AL = 2.7 to 5.5V, 0 to +70°C, V
TRIP
=4.63V±112mV
1288AM = 2.7 to 5.5V, -40 to +85°C, V
TRIP
=4.63V±112mV
X1288
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Preliminary Information
PIN ASSIGNMENTS
Pin Number
SOIC
1
X1288
TSSOP Symbol
1
X1
Brief Description
X1.
The X1 pin is the input of an inverting amplifier. An external 32.768kHz quartz
crystal is used with the X1288 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 information.
X2.
The X2 pin is the output of an inverting amplifier. An external 32.768kHz quartz
crystal is used with the X1288 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 information.
RESET Output – RESET.
This is a reset signal output. This signal notifies a host
processor that the watchdog time period has expired or that the voltage has dropped
below a fixed V
TRIP
threshold. It is an open drain active LOW output. Recommended
value for the pullup resistor is 5K Ohms. If unused, tie to ground.
V
SS
.
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 pull-down. 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).
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 15..
V
BACK
.
This input provides a backup supply voltage to the device. V
BACK
supplies
power to the device in the event the V
CC
supply fails. This pin can be connected to a
battery, a Supercap or tied to ground if not used.
V
CC
.
2
2
X2
7
6
RESET
8
9
7
8
V
SS
SDA
10
14
9
12
SCL
PHZ/IRQ
15
13
V
BACK
16
14
V
CC
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Preliminary Information
ABSOLUTE MAXIMUM RATINGS
Temperature Under Bias ................... -65°C to +135°C
Storage Temperature......................... -65°C to +150°C
Voltage on V
CC
, V
BACK
and PHZ/IRQ
pin (respect to ground) ............................-0.5V to 7.0V
Voltage on SCL, SDA, X1 and X2
pin (respect to ground) ............... -0.5V to 7.0V or 0.5V
above V
CC
or V
BACK
(whichever is higher)
DC Output Current .............................................. 5 mA
Lead Temperature (Soldering, 10 sec) ...............300°C
X1288
Stresses above those listed under “Absolute Maximum
Ratings” may cause permanent damage to the device.
This is a stress rating only and the functional operation
of the device at these or any other conditions above
those indicated in the operational sections of this spec-
ification is not implied. Exposure to absolute maximum
rating conditions for extended periods may affect
device reliability.
DC OPERATING CHARACTERISTICS
(Temperature = -40°C to +85°C, unless otherwise stated.)
Symbol
V
CC
V
BACK
V
CB
V
BC
Parameter
Main Power Supply
Backup Power Supply
Switch to Backup Supply
Switch to Main Supply
Conditions
Min
2.7
1.8
V
BACK
-0.2
V
BACK
Typ
Max
5.5
5.5
V
BACK
-0.1
V
BACK
+0.2
Unit
V
V
V
V
Notes
OPERATING CHARACTERISTICS
Symbol
I
CC1
I
CC2
I
CC3
I
BACK
Parameter
Read Active Supply
Current
Program Supply Current
(nonvolatile)
Main Timekeeping
Current
Timekeeping Current –
(Low Voltage Sense and
Watchdog Timer dis-
abled
Input Leakage Current
Output Leakage Current
Input LOW Voltage
Input HIGH Voltage
Schmitt Trigger Input
Hysteresis
Output LOW Voltage for
SDA and RESET
Output LOW Voltage for
PHZ/IRQ
Output HIGH Voltage for
PHZ/IRQ
Conditions
V
CC
= 2.7V
V
CC
= 5.0V
V
CC
= 2.7V
V
CC
= 5.0V
V
CC
= 2.7V
V
CC
= 5.0V
V
BACK
= 1.8V
V
BACK
= 3.3V
Min
Typ
Max
400
800
2.5
3.0
10
20
Unit
µA
µA
mA
mA
µA
µA
µA
µA
Notes
1, 5, 7, 14
2, 5, 7, 14
3, 7, 8, 14, 15
3, 6, 9, 14, 15
“See Perfor-
mance Data”
1.25
1.5
10
10
-0.5
V
CC
x 0.7 or
V
BACK
x 0.7
V
CC
x 0.2 or
V
BACK
x 0.2
V
CC
+ 0.5 or
V
BACK
+ 0.5
I
LI
I
LO
V
IL
V
IH
V
HYS
V
OL1
V
OL2
V
OH2
µA
µA
V
V
V
10
10
13
13
13
11
11
12
V
CC
related level
V
CC
= 2.7V
V
CC
= 5.5V
V
CC
= 2.7V
V
CC
= 5.5V
V
CC
= 2.7V
V
CC
= 5.5V
.05 x V
CC
or
.05 x V
BACK
0.4
0.4
V
CC
x 0.3
V
CC
x 0.3
V
CC
x 0.7
V
CC
x 0.7
V
V
V
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