PCF2127AT/1,518 NXP Semiconductors, PCF2127AT/1,518 Datasheet - Page 23
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PCF2127AT/1,518
Manufacturer Part Number
PCF2127AT/1,518
Description
IC RTC/CALENDAR TCXO QTZ 20SOIC
Manufacturer
NXP Semiconductors
Type
Clock/Calendar/Alarmr
Datasheet
1.PCF2127AT1518.pdf
(80 pages)
Specifications of PCF2127AT/1,518
Package / Case
20-SOIC (0.300", 7.50mm Width)
Time Format
HH:MM:SS (12/24 hr)
Memory Size
512B
Date Format
YY-MM-DD-dd
Interface
I²C, 2-Wire Serial
Voltage - Supply
1.8 V ~ 4.2 V
Operating Temperature
-40°C ~ 85°C
Mounting Type
Surface Mount
Function
Serial Clock, Timestamp, Timekeeper, Watchdog, Alarm, Calendar, Timer, Timer Interrupt
Rtc Memory Size
512 bytes
Supply Voltage (max)
4.2 V
Supply Voltage (min)
1.8 V
Mounting Style
SMD/SMT
Rtc Bus Interface
I2C
Supply Current
2600 nA
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
NXP Semiconductors
PCF2127A_2
Product data sheet
8.6.4.1 Extra power fail detection when the battery switch over function is enabled
V
below the minimum operating voltage of the system, in order to allow the microcontroller
to perform early backup operations.
If the extra power fail detection function is not used, pin PFI must be connected to V
pin PFO must be left open circuit.
For illustration see
V
Fig 10. PFO signal behavior when battery switch-over is enabled in standard mode and
th(uvp)
•
•
th uvp
V
comparator
DD
enabled
(
V
(= 2.5 V)
When the power switches to the backup battery supply V
comparator is switched off and the power fail output at pin PFO goes (or remains)
LOW
When the power switches back to the main V
anymore and is pulled HIGH through the external pull-up resistance for a certain time
(t
th(sw)bat
V
(= 0 V)
rec
th(uvp)
V
)
V
PF0
value is usually set to a value that there are several milliseconds before V
BAT
DD
=
= 15.63 ms to 31.25 ms) and then the power fail comparator is enabled again
V
⎛
⎝
th(uvp)
R
----- -
R
1
2
+
All information provided in this document is subject to legal disclaimers.
> (V
1
⎞
⎠
Figure 10
V
×
BBS
BAT
1.25V
, V
Rev. 02 — 7 May 2010
th(sw)bat
and
)
internal power supply (= V
Figure
11.
Integrated RTC, TCXO and quartz crystal
comparator
disabled
DD
BBS
, the pin PFO is not driven LOW
)
t
rec
BAT
= [15.63 : 31.25] ms
, the power fail
V
BBS
PCF2127A
© NXP B.V. 2010. All rights reserved.
comparator
DD
enabled
001aaj319
SS
23 of 80
falls
and
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