PCF2123BS/1,512 NXP Semiconductors, PCF2123BS/1,512 Datasheet - Page 30

• Manufacturer Part Number: PCF2123BS/1,512
• Description: IC CLOCK HVQFN16
• Manufacturer: NXP Semiconductors
• Type: Clock/Calendar/Alarmr

Specifications of PCF2123BS/1,512

• Package / Case: 16-VQFN Exposed Pad, 16-HVQFN, 16-SQFN, 16-DHVQFN
• Time Format: HH:MM:SS (12/24 hr)
• Date Format: YY-MM-DD-dd
• Interface: SPI, 3-Wire Serial
• Voltage - Supply: 1.1 V ~ 5.5 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Function: Clock, Calendar, Alarm, Watchdog
• Supply Voltage (max): 5.5 V
• Supply Voltage (min): 1.1 V
• Maximum Operating Temperature: + 85 C
• Minimum Operating Temperature: - 40 C
• Mounting Style: SMD/SMT
• Rtc Bus Interface: SPI
• Supply Current: 250 uA
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Memory Size: -
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Lead free / RoHS Compliant
• Other names: 568-5051-5; 935286382512

NXP Semiconductors
PCF2123
Product data sheet
8.9 Offset register
The PCF2123 incorporates an offset register (address 0Dh) which can be used to
implement several functions, such as:
The offset is made once every two hours in the normal mode, or once every hour in the
course mode. Each LSB will introduce an offset of 2.17 ppm for normal mode and
4.34 ppm for course mode. The values of 2.17 ppm and 4.34 ppm are based on a nominal
32.768 kHz clock. The offset value is coded in two’s complement giving a range of
+63 LSB to 64 LSB.
Table 36.
[1]
The correction is made by adding or subtracting 64 Hz clock correction pulses, thereby
changing the period of a single second.
Table 37.
In normal mode, the correction is triggered once per two hours and then correction pulses
are applied once per minute until the programmed correction values have been
implement.
In course mode, the correction is triggered once per hour and then correction pulses are
applied once per minute up to a maximum of 60 minutes. When correction values greater
than 60 are used, additional correction pulses are made in the 59th minute (see
OFFSET[6:0]
0 1 1 1 1 1 1
0 1 1 1 1 1 0
0 0 0 0 0 1 0
0 0 0 0 0 0 1
0 0 0 0 0 0 0
1 1 1 1 1 1 1
1 1 1 1 1 1 0
1 0 0 0 0 0 1
1 0 0 0 0 0 0
Offset in ppm
2.17
4.34
•
•
•
Ageing adjustment
Temperature compensation
Accuracy tuning
Default mode.
:
:
Register Offset_register
Example of converting the offset in ppm to seconds
All information provided in this document is subject to legal disclaimers.
Seconds per
Day
0.187
0.375
Offset value in
decimal
+63
+62
:
+2
+1
0
1
2
:
63
64
Rev. 4 — 22 December 2010
[1]
Week
1.31
2.62
+136.71
+134.54
+4.34
+2.17
2.17
4.34
:
136.71
138.88
Offset value in ppm
Normal mode
MODE = 0
:
0
Month
5.69
11.4
SPI Real time clock/calendar
Course mode
MODE = 1
+273.42
+269.08
:
+8.68
+4.34
0
4.34
8.68
:
273.42
277.76
PCF2123
© NXP B.V. 2010. All rights reserved.
Year
68.2
136
Table
30 of 61
38).