PCA85073A
Automotive tiny Real-Time Clock/calendar with alarm function
and I2C-bus
Rev. 1 — 4 October 2019
Product data sheet
1. General description
The PCA85073A is a CMOS1 Real-Time Clock (RTC) and calendar optimized for low
power consumption. An offset register allows fine-tuning of the clock. All addresses and
data are transferred serially via the two-line bidirectional I2C-bus. Maximum data rate is
400 kbit/s. The register address is incremented automatically after each written or read
data byte.
For a selection of NXP Real-Time Clocks, see Table 44 on page 51
2. Features and benefits
AEC-Q100 grade 2 compliant for automotive applications
Provides year, month, day, weekday, hours, minutes, and seconds based on a
32.768 kHz quartz crystal
Low current; typical 0.25 A at VDD = 3.0 V and Tamb = 25 C
Programmable clock output for peripheral devices (32.768 kHz, 16.384 kHz,
8.192 kHz, 4.096 kHz, 2.048 kHz, 1.024 kHz, and 1 Hz)
Alarm function
Minute and half minute interrupt
Internal Power-On Reset (POR)
High temperature operation range: 40 C to +105 C
Clock operating voltage: 0.9 V to 5.5 V
400 kHz two-line I2C-bus interface
(at VDD = 1.8 V to 5.5 V)
Selectable integrated oscillator load capacitors for CL = 7 pF or CL = 12.5 pF
Countdown timer
Oscillator stop detection function
Programmable offset register for frequency adjustment
Latch-up performance exceeds 100 mA per JESD 78, Class II
ESD protection exceeds JESD 22
4000 V Human-Body Model (A114-A)
1000 V Charged-Device Model (C101)
Package offered: TSSOP8
1.
The definition of the abbreviations and acronyms used in this data sheet can be found in Section 21.
PCA85073A
NXP Semiconductors
Automotive Real-Time Clock/calendar with alarm function and I2C-bus
3. Applications
Tracking time of the day
Dashboard
Air condition
Telematics
Accurate timing
Infotainment unit
Center stack
Body control and battery management
4. Ordering information
Table 1.
Ordering information
Type number
Topside Package
marking Name
PCA85073ADP/Q900[1]
[1]
073Q
TSSOP8
Description
Version
plastic thin shrink small outline package; 8 leads; body
width 3 mm
SOT505-1
Drop-in replacement for PCA85063ATT/A. The PCA85073ADP/Q900 leadframe is rougher for higher resistance to package
delamination.
4.1 Ordering options
Table 2.
Ordering options
Type number
Orderable part number Package Packing method
Minimum
order
quantity
Temperature
PCA85073ADP/Q900
PCA85073ADP/Q900Z
2500
Tamb = 40 C to +105 C
[1]
TSSOP8 REEL 13” Q1
NDP SSB[1]
This Packing Method uses a Static Shielding Bag (SSB) solution. Material shall be kept in the sealed bag between uses.
PCA85073A
Product data sheet
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Rev. 1 — 4 October 2019
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PCA85073A
NXP Semiconductors
Automotive Real-Time Clock/calendar with alarm function and I2C-bus
5. Block diagram
OSCO
OSCI
32 kHz
OSCILLATOR
DIVIDER
POWER-ON
RESET
CLOCK
CALIBRATION
OFFSET
VDD
SYSTEM
CONTROL
CLOCK OUT
CLKOUT
INTERRUPT
CONTROL
INT
VSS
SDA
SCL
l2C-BUS
INTERFACE
REAL-TIME
CLOCK
ALARM AND
TIMER
CONTROL
PCA85073A
aaa-032100
Fig 1.
PCA85073A
Product data sheet
Block diagram of PCA85073A
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PCA85073A
NXP Semiconductors
Automotive Real-Time Clock/calendar with alarm function and I2C-bus
6. Pinning information
6.1 Pinning
PCA85073ADP/Q900
OSCI 1
8 VDD
OSCO 2
7 CLKOUT
INT 3
6 SCL
VSS 4
5 SDA
aaa-032101
For mechanical details, see Figure 30.
Fig 2.
Pin configuration for TSSOP8 (PCA85073ADP)
6.2 Pin description
Table 3.
Pin description
Input or input/output pins must always be at a defined level (VSS or VDD) unless otherwise specified.
Symbol
Pin
Type
Description
OSCI
1
input
oscillator input
OSCO
2
output
oscillator output
INT[1]
3
output
interrupt output (open-drain)
VSS
4
supply
ground supply voltage
SDA[1]
5
input/output
serial data line
SCL[1]
6
input
serial clock input
CLKOUT
7
output
clock output (push-pull)
VDD
8
supply
supply voltage
[1]
PCA85073A
Product data sheet
NXP recommends tying VDD of the device and VDD of all the external pull-up resistors to the same Power
Supply.
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PCA85073A
NXP Semiconductors
Automotive Real-Time Clock/calendar with alarm function and I2C-bus
7. Functional description
The PCA85073A contains 18 8-bit registers with an auto-incrementing register address,
an on-chip 32.768 kHz oscillator with integrated capacitors, a frequency divider which
provides the source clock for the Real-Time Clock (RTC) and calender, and an I2C-bus
interface with a maximum data rate of 400 kbit/s.
The built-in address register will increment automatically after each read or write of a data
byte up to the register 11h. After register 11h, the auto-incrementing will wrap around to
address 00h (see Figure 3).
address register
00h
01h
02h
auto-increment
03h
...
0Fh
10h
11h
wrap around
aaa-004431
Fig 3.
Handling address registers
All registers (see Table 4) are designed as addressable 8-bit parallel registers although
not all bits are implemented. The first two registers (memory address 00h and 01h) are
used as control and status register. The register at address 02h is an offset register
allowing the fine-tuning of the clock; and at 03h is a free RAM byte. The addresses 04h
through 0Ah are used as counters for the clock function (seconds up to years counters).
Address locations 0Bh through 0Fh contain alarm registers which define the conditions for
an alarm. The registers at 10h and 11h are for the timer function.
The Seconds, Minutes, Hours, Days, Months, and Years as well as the corresponding
alarm registers are all coded in Binary Coded Decimal (BCD) format. When one of the
RTC registers is written or read, the contents of all time counters are frozen. Therefore,
faulty writing or reading of the clock and calendar during a carry condition is prevented.
For details on maximum access time, see Section 7.4 on page 24.
PCA85073A
Product data sheet
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Rev. 1 — 4 October 2019
© NXP B.V. 2019. All rights reserved.
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NXP Semiconductors
PCA85073A
Product data sheet
7.1 Registers organization
Table 4.
Registers overview
Bit positions labeled as - are not implemented. After reset, all registers are set according to Table 7 on page 11.
Address
Register name
Bit
Reference
7
6
5
4
3
2
1
0
12_24
CAP_SEL
Control and status registers
00h
Control_1
EXT_TEST
-
STOP
SR
-
CIE
01h
Control_2
AIE
AF
MI
HMI
TF
COF[2:0]
02h
Offset
MODE
OFFSET[6:0]
03h
RAM_byte
B[7:0]
Section 7.2.1
Section 7.2.2
Section 7.2.3
Section 7.2.4
Rev. 1 — 4 October 2019
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04h
Seconds
OS
SECONDS (0 to 59)
Section 7.3.1
05h
Minutes
-
MINUTES (0 to 59)
Section 7.3.2
06h
Hours
-
-
07h
Days
-
-
DAYS (1 to 31)
08h
Weekdays
-
-
-
-
09h
Months
-
-
-
MONTHS (1 to 12)
0Ah
Years
YEARS (0 to 99)
Section 7.3.7
AMPM
HOURS (1 to 12) in 12-hour mode
Section 7.3.3
HOURS (0 to 23) in 24-hour mode
Section 7.3.4
-
WEEKDAYS (0 to 6)
Section 7.3.5
Section 7.3.6
Alarm registers
0Bh
Second_alarm
AEN_S
SECOND_ALARM (0 to 59)
Section 7.5.1
0Ch
Minute_alarm
AEN_M
MINUTE_ALARM (0 to 59)
Section 7.5.2
0Dh
Hour_alarm
AEN_H
-
AMPM
HOUR_ALARM (1 to 12) in 12-hour mode
Section 7.5.3
HOUR_ALARM (0 to 23) in 24-hour mode
Day_alarm
AEN_D
-
DAY_ALARM (1 to 31)
0Fh
Weekday_alarm
AEN_W
-
-
-
Section 7.5.4
-
WEEKDAY_ALARM (0 to 6)
Section 7.5.5
Timer registers
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10h
Timer_value
T[7:0]
11h
Timer_mode
-
Section 7.6.1
-
-
TCF[1:0]
TE
TIE
TI_TP
Section 7.6.2
PCA85073A
0Eh
Automotive Real-Time Clock/calendar with alarm function and I2C-bus
Time and date registers
PCA85073A
NXP Semiconductors
Automotive Real-Time Clock/calendar with alarm function and I2C-bus
7.2 Control registers
To ensure that all control registers will be set to their default values, the VDD level must be
at zero volts at initial power-up. If this is not possible, a reset must be initiated with the
software reset command when power is stable. Refer to Section 7.2.1.3 for details.
7.2.1 Register Control_1
Table 5.
Control_1 - control and status register 1 (address 00h) bit description
Bit
Symbol
7
EXT_TEST
Value
0[1]
1
6
-
5
STOP
4
0
-
2
CIE
1
external clock test mode
Section 7.2.1.1
normal mode
external clock test mode
unused
-
STOP bit
Section 7.2.1.2
RTC clock runs
1
RTC clock is stopped; all RTC divider chain
flip-flops are asynchronously set logic 0
software reset
0[1]
no software reset
1
initiate software reset[2]; this bit always
returns a 0 when read
0
-
correction interrupt enable
Section 7.2.3
no correction interrupt generated
1
interrupt pulses are generated at every
correction cycle
12 or 24-hour mode
0[1]
24-hour mode is selected
1
12-hour mode is selected
CAP_SEL
internal oscillator capacitor selection for
quartz crystals with a corresponding load
capacitance
0[1]
7 pF
1
12.5 pF
[1]
Default value.
[2]
For a software reset, 01011000 (58h) must be sent to register Control_1 (see Section 7.2.1.3).
PCA85073A
Product data sheet
Section 7.2.1.3
unused
0[1]
12_24
0
Reference
0[1]
SR
3
Description
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Rev. 1 — 4 October 2019
Section 7.3.3
Section 7.5.3
-
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PCA85073A
NXP Semiconductors
Automotive Real-Time Clock/calendar with alarm function and I2C-bus
7.2.1.1
EXT_TEST: external clock test mode
A test mode is available which allows for on-board testing. In this mode, it is possible to
set up test conditions and control the operation of the RTC.
The test mode is entered by setting bit EXT_TEST in register Control_1. Then
pin CLKOUT becomes an input. The test mode replaces the internal clock signal with the
signal applied to pin CLKOUT.
The signal applied to pin CLKOUT should have a minimum pulse width of 300 ns and a
maximum period of 1000 ns. The internal clock, now sourced from CLKOUT, is divided
down to 1 Hz by a 26 divide chain called a prescaler. The prescaler can be set into a
known state by using bit STOP. When bit STOP is set, the prescaler is reset to 0. (STOP
must be cleared before the prescaler can operate again.)
From a stop condition, the first 1 second increment will take place after 32 positive edges
on pin CLKOUT. Thereafter, every 64 positive edges cause a 1 second increment.
Remark: Entry into test mode is not synchronized to the internal 64 Hz clock. When
entering the test mode, no assumption as to the state of the prescaler can be made.
Operation example:
1. Set EXT_TEST test mode (register Control_1, bit EXT_TEST = 1).
2. Set STOP (register Control_1, bit STOP = 1).
3. Clear STOP (register Control_1, bit STOP = 0).
4. Set time registers to desired value.
5. Apply 32 clock pulses to pin CLKOUT.
6. Read time registers to see the first change.
7. Apply 64 clock pulses to pin CLKOUT.
8. Read time registers to see the second change.
Repeat 7 and 8 for additional increments.
PCA85073A
Product data sheet
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PCA85073A
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Automotive Real-Time Clock/calendar with alarm function and I2C-bus
7.2.1.2
STOP: STOP bit function
The function of the STOP bit (see Figure 4) is to allow for accurate starting of the time
circuits. The STOP bit function causes the upper part of the prescaler (F2 to F14) to be
held in reset and thus no 1 Hz ticks are generated. It also stops the output of clock
frequencies below 8 kHz on pin CLKOUT.
OSCILLATOR STOP
DETECTOR
OSCILLATOR
32768 Hz
F0
16384 Hz
F1
8192 Hz
F2
setting the OS flag
4096 Hz
RESET
F13
RESET
2 Hz
F14
1 Hz tick
RESET
STOP
aaa-004415
Fig 4.
STOP bit functional diagram
The time circuits can then be set and do not increment until the STOP bit is released (see
Figure 5 and Table 6).
PCA85073A
Product data sheet
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Automotive Real-Time Clock/calendar with alarm function and I2C-bus
Table 6.
First increment of time circuits after STOP bit release
Bit
Prescaler bits
STOP
F0F1-F2 to F14
[1]
1 Hz tick
Time
Comment
hh:mm:ss
Clock is running normally
0
12:45:12
01-0 0001 1101 0100
prescaler counting normally
STOP bit is activated by user. F0F1 are not reset and values cannot be predicted externally
1
XX-0 0000 0000 0000
12:45:12
prescaler is reset; time circuits are frozen
08:00:00
prescaler is reset; time circuits are frozen
New time is set by user
1
XX-0 0000 0000 0000
STOP bit is released by user
0
XX-0 0000 0000 0000
08:00:00
prescaler is now running
XX-1 0000 0000 0000
08:00:00
-
08:00:00
-
08:00:00
-
XX-0 1000 0000 0000
XX-1 1000 0000 0000
0.507813
to
0.507935 s
:
:
:
11-1 1111 1111 1110
08:00:00
-
00-0 0000 0000 0001
08:00:01
0 to 1 transition of F14 increments the time circuits
10-0 0000 0000 0001
08:00:01
-
:
:
:
11-1 1111 1111 1111
08:00:01
-
00-0 0000 0000 0000
08:00:01
-
10-0 0000 0000 0000
08:00:01
-
:
:
:
11-1 1111 1111 1110
08:00:01
-
00-0 0000 0000 0001
08:00:02
0 to 1 transition of F14 increments the time circuits
1.000000 s
aaa-004416
[1]
F0 is clocked at 32.768 kHz.
The lower two stages of the prescaler (F0 and F1) are not reset. And because the I2C-bus
is asynchronous to the crystal oscillator, the accuracy of restarting the time circuits is
between zero and one 8.192 kHz cycle (see Figure 5).
8192 Hz
stop released
0 μs to 122 μs
Fig 5.
aaa-004417
STOP bit release timing
The first increment of the time circuits is between 0.507813 s and 0.507935 s after STOP
bit is released. The uncertainty is caused by the prescaler bits F0 and F1 not being reset
(see Table 6) and the unknown state of the 32 kHz clock.
PCA85073A
Product data sheet
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PCA85073A
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Automotive Real-Time Clock/calendar with alarm function and I2C-bus
7.2.1.3
Software reset
A reset is automatically generated at power-on. A reset can also be initiated with the
software reset command. Software reset command means setting bits 6, 4, and 3 in
register Control_1 (00h) logic 1 and all other bits logic 0 by sending the bit sequence
01011000 (58h), see Figure 6.
slave address
SDA
s
1
0
1
0
0
address 00h
R/W
0
1
0
A
0
0
0
0
0
0
software reset 58h
0
0
A
0
1
0
1
1
0
0
A P/S
0
SCL
internal
reset signal
aaa-004418
After sending the software reset command, it is recommended to re-initialize the interface by a STOP and START.
Fig 6.
Software reset command
In reset state, all registers are set according to Table 7 and the address pointer returns to
address 00h.
PCA85073A
Product data sheet
Table 7.
Registers reset values
Address
Register name
Bit
7
6
5
4
3
2
1
0
00h
Control_1
0
0
0
0
0
0
0
0
01h
Control_2
0
0
0
0
0
0
0
0
02h
Offset
0
0
0
0
0
0
0
0
03h
RAM_byte
0
0
0
0
0
0
0
0
04h
Seconds
1
0
0
0
0
0
0
0
05h
Minutes
0
0
0
0
0
0
0
0
06h
Hours
0
0
0
0
0
0
0
0
07h
Days
0
0
0
0
0
0
0
1
08h
Weekdays
0
0
0
0
0
1
1
0
09h
Months
0
0
0
0
0
0
0
1
0Ah
Years
0
0
0
0
0
0
0
0
0Bh
Second_alarm
1
0
0
0
0
0
0
0
0Ch
Minute_alarm
1
0
0
0
0
0
0
0
0Dh
Hour_alarm
1
0
0
0
0
0
0
0
0Eh
Day_alarm
1
0
0
0
0
0
0
0
0Fh
Weekday_alarm
1
0
0
0
0
0
0
0
10h
Timer_value
0
0
0
0
0
0
0
0
11h
Timer_mode
0
0
0
1
1
0
0
0
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PCA85073A
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Automotive Real-Time Clock/calendar with alarm function and I2C-bus
The PCA85073A resets to:
Time — 00:00:00
Date — 20000101
Weekday — Saturday
7.2.2 Register Control_2
Table 8.
Control_2 - control and status register 2 (address 01h) bit description
Bit
Symbol
7
AIE
Value
0[1]
Reference
alarm interrupt
Section 7.2.2.1
Section 7.5.6
disabled
1
6
Description
enabled
AF
alarm flag
0[1]
read: alarm flag inactive
Section 7.2.2.1
Section 7.5.6
write: alarm flag is cleared
1
read: alarm flag active
write: alarm flag remains unchanged
5
MI
minute interrupt
0[1]
disabled
1
4
half minute interrupt
0[1]
disabled
1
enabled
TF
2 to 0
[1]
enabled
HMI
3
COF[2:0]
Section 7.2.2.2
Section 7.2.2.3
timer flag
0[1]
no timer interrupt generated
1
flag set when timer interrupt generated
see Table 10
CLKOUT control
Section 7.2.2.2
Section 7.2.2.3
Section 7.2.2.1
Section 7.2.2.3
Section 7.6.3
Section 7.2.2.4
Default value.
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Product data sheet
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Automotive Real-Time Clock/calendar with alarm function and I2C-bus
7.2.2.1
Alarm interrupt
HMI
SECONDS COUNTER
HMI/MI
MINUTES COUNTER
HMI MI
0
SET
MI
CLEAR
1
PULSE
GENERATOR 1
TRIGGER
CLEAR
from interface:
clear TF
TI_TP
TIMER FLAG
TF
SET
COUNTDOWN COUNTER
CLEAR
TE
to interface:
read TF
TIE
0
PULSE
GENERATOR 2
TRIGGER
1
INT
CLEAR
set alarm
flag, AF
ALARM FLAG
AF
SET
to interface:
read AF
AIE
example
AIE
CLEAR
from interface:
clear AF
offset circuit:
add/substract
pulse
PULSE
GENERATOR 3
TRIGGER
CIE
0
1
CLEAR
from interface:
set CIE
Fig 7.
aaa-004432
Interrupt scheme
AIE: This bit activates or deactivates the generation of an interrupt when AF is asserted,
respectively.
AF: When an alarm occurs, AF is set logic 1. This bit maintains its value until overwritten
by command. To prevent one flag being overwritten while clearing another, a logic AND is
performed during a write access.
PCA85073A
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Automotive Real-Time Clock/calendar with alarm function and I2C-bus
7.2.2.2
MI and HMI: minute and half minute interrupt
The minute interrupt (bit MI) and half minute interrupt (bit HMI) are pre-defined timers for
generating interrupt pulses on pin INT; see Figure 8. The timers are running in sync with
the seconds counter (see Table 18 on page 20).
The minute and half minute interrupts must only be used when the frequency offset is set
to normal mode (MODE = 0), see Section 7.2.3. In normal mode, the interrupt pulses on
pin INT are 1⁄64 s wide.
When starting MI, the first interrupt will be generated after 1 second to 59 seconds. When
starting HMI, the first interrupt will be generated after 1 second to 29 seconds.
Subsequent periods do not have such a delay. The timers can be enabled independently
from one another. However, a minute interrupt enabled on top of a half minute interrupt is
not distinguishable.
seconds counter
58
59
minutes counter
59
00
11
12
00
01
INT when MI enabled
TF when MI enabled
aaa-004419
In this example, the TF flag is not cleared after an interrupt.
Fig 8.
Table 9.
INT example for MI
Effect of bits MI and HMI on INT generation
Minute interrupt (bit MI)
Half minute interrupt (bit HMI)
Result
0
0
no interrupt generated
1
0
an interrupt every minute
0
1
an interrupt every 30 s
1
1
an interrupt every 30 s
The duration of the timer is affected by the register Offset (see Section 7.2.3). Only when
OFFSET[6:0] has the value 00h the periods are consistent.
7.2.2.3
TF: timer flag
The timer flag (bit TF) is set logic 1 on the first trigger of MI, HMI, or the countdown timer.
The purpose of the flag is to allow the controlling system to interrogate what caused the
interrupt: timer or alarm. The flag can be read and cleared by command.
The status of the timer flag TF can affect the INT pulse generation depending on the
setting of TI_TP (see Section 7.6.2 “Register Timer_mode” on page 29):
• When TI_TP is set logic 1
– an INT pulse is generated independent of the status of the timer flag TF
– TF stays set until it is cleared
– TF does not affect INT
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Product data sheet
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Automotive Real-Time Clock/calendar with alarm function and I2C-bus
– the countdown timer runs in a repetitive loop and keeps generating timed periods
• When TI_TP is set logic 0
– the INT generation follows the TF flag
– TF stays set until it is cleared
– If TF is not cleared before the next coming interrupt, no INT is generated
– the countdown timer stops after the first countdown
7.2.2.4
COF[2:0]: Clock output frequency
A programmable square wave is available at pin CLKOUT. Operation is controlled by the
COF[2:0] bits in the register Control_2. Frequencies of 32.768 kHz (default) down to 1 Hz
can be generated for use as a system clock, microcontroller clock, input to a charge
pump, or for calibration of the oscillator.
Pin CLKOUT is a push-pull output and enabled at power-on. CLKOUT can be disabled by
setting COF[2:0] to 111. When disabled, the CLKOUT is LOW.
The duty cycle of the selected clock is not controlled. However, due to the nature of the
clock generation, all clock frequencies except 32.768 kHz have a duty cycle of 50 : 50.
The STOP bit function can also affect the CLKOUT signal, depending on the selected
frequency. When the STOP bit is set logic 1, the CLKOUT pin generates a continuous
LOW for those frequencies that can be stopped. For more details of the STOP bit function,
see Section 7.2.1.2.
Table 10.
PCA85073A
Product data sheet
CLKOUT frequency selection
COF[2:0]
CLKOUT frequency (Hz) Typical duty cycle[1]
Effect of STOP bit
000[2]
32768
60 : 40 to 40 : 60
no effect
001
16384
50 : 50
no effect
010
8192
50 : 50
no effect
011
4096
50 : 50
CLKOUT = LOW
100
2048
50 : 50
CLKOUT = LOW
101
1024
50 : 50
CLKOUT = LOW
110
1[3]
50 : 50
CLKOUT = LOW
111
CLKOUT = LOW
-
-
[1]
Duty cycle definition: % HIGH-level time : % LOW-level time.
[2]
Default value.
[3]
1 Hz clock pulses are affected by offset correction pulses.
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Automotive Real-Time Clock/calendar with alarm function and I2C-bus
7.2.3 Register Offset
The PCA85073A incorporates an offset register (address 02h) which can be used to
implement several functions, such as:
• Accuracy tuning
• Aging adjustment
• Temperature compensation
Table 11.
Offset - offset register (address 02h) bit description
Bit
Symbol
7
MODE
6 to 0
[1]
Value
Description
offset mode
OFFSET[6:0]
0[1]
normal mode: offset is made once every two
hours
1
course mode: offset is made every 4 minutes
offset value
see Table 12
Default value.
For MODE = 0, each LSB introduces an offset of 4.34 ppm. For MODE = 1, each LSB
introduces an offset of 4.069 ppm. The offset value is coded in two’s complement giving a
range of +63 LSB to 64 LSB.
Table 12.
Offset values
OFFSET[6:0]
Offset value in
decimal
Offset value in ppm
Normal mode
MODE = 0
Fast mode
MODE = 1
0111111
+63
+273.420
+256.347
0111110
+62
+269.080
+252.278
:
:
:
:
0000010
+2
+8.680
+8.138
0000001
+1
+4.340
+4.069
0000000[1]
0
0[1]
0[1]
1111111
1
4.340
4.069
1111110
2
8.680
8.138
:
:
:
:
1000001
63
273.420
256.347
1000000
64
277.760
260.416
[1]
Default value.
The correction is made by adding or subtracting clock correction pulses, thereby changing
the period of a single second but not by changing the oscillator frequency.
It is possible to monitor when correction pulses are applied. To enable correction interrupt
generation, bit CIE (register Control_1) has to be set logic 1. At every correction cycle, a
pulse is generated on pin INT. The pulse width depends on the correction mode. If
multiple correction pulses are applied, an interrupt pulse is generated for each correction
pulse applied.
PCA85073A
Product data sheet
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Automotive Real-Time Clock/calendar with alarm function and I2C-bus
7.2.3.1
Correction when MODE = 0
The correction is triggered once every two hours and then correction pulses are applied
once per minute until the programmed correction values have been implemented.
Table 13.
Correction pulses for MODE = 0
Correction value
Update every nth hour Minute
+1 or 1
2
00
1
+2 or 2
2
00 and 01
1
+3 or 3
2
00, 01, and 02
1
:
:
:
:
Correction pulses on
INT per minute[1]
+59 or 59
2
00 to 58
1
+60 or 60
2
00 to 59
1
+61 or 61
2
00 to 59
1
2nd and next hour
00
1
+62 or 62
+63 or 63
64
[1]
2
00 to 59
1
2nd and next hour
00 and 01
1
02
00 to 59
1
2nd and next hour
00, 01, and 02
1
02
00 to 59
1
2nd and next hour
00, 01, 02, and 03
1
The correction pulses on pin INT are 1⁄64 s wide.
In MODE = 0, any timer or clock output using a frequency below 64 Hz is affected by the
clock correction (see Table 14).
Table 14.
Effect of correction pulses on frequencies for MODE = 0
Frequency (Hz)
Effect of correction
CLKOUT
32768
no effect
16384
no effect
8192
no effect
4096
no effect
2048
no effect
1024
no effect
1
affected
Timer source clock
PCA85073A
Product data sheet
4096
no effect
64
no effect
1
affected
1⁄
60
affected
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Automotive Real-Time Clock/calendar with alarm function and I2C-bus
7.2.3.2
Correction when MODE = 1
The correction is triggered once every four minutes and then correction pulses are applied
once per second up to a maximum of 60 pulses. When correction values greater than 60
pulses are used, additional correction pulses are made in the 59th second.
Clock correction is made more frequently in MODE = 1; however, this can result in higher
power consumption.
Table 15.
Correction pulses for MODE = 1
Correction value
Update every nth
minute
Second
Correction pulses on
INT per second[1]
+1 or 1
2
00
1
+2 or 2
2
00 and 01
1
+3 or 3
2
00, 01, and 02
1
:
:
:
:
+59 or 59
2
00 to 58
1
+60 or 60
2
00 to 59
1
+61 or 61
2
00 to 58
1
2
59
2
2
00 to 58
1
2
59
3
2
00 to 58
1
2
59
4
2
00 to 58
1
2
59
5
+62 or 62
+63 or 63
64
[1]
The correction pulses on pin INT are 1⁄1024 s wide. For multiple pulses, they are repeated at an interval of
s.
1⁄
512
In MODE = 1, any timer source clock using a frequency below 1.024 kHz is also affected
by the clock correction (see Table 16).
Table 16.
Effect of correction pulses on frequencies for MODE = 1
Frequency (Hz)
Effect of correction
CLKOUT
32768
no effect
16384
no effect
8192
no effect
4096
no effect
2048
no effect
1024
no effect
1
affected
Timer source clock
4096
PCA85073A
Product data sheet
no effect
64
affected
1
affected
1⁄
60
affected
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Automotive Real-Time Clock/calendar with alarm function and I2C-bus
7.2.3.3
Offset calibration workflow
The calibration offset has to be calculated based on the time. Figure 9 shows the workflow
how the offset register values can be calculated:
Measure the frequency on pin CLKOUT:
fmeas
sample calculation:
32768.48 Hz
Convert to time:
tmeas = 1 / fmeas
30.517131 μs
Calculate the difference to the ideal
period of 1 / 32768.00:
Dmeas = 1 / 32768 - tmeas
0.000447 μs
Calculate the ppm deviation compared
to the measured value:
Eppm = 1000000 × Dmeas / tmeas
14.648 ppm
Calculate the offset register value:
Mode = 0 (low power):
Offset value = Eppm / 4.34
3.375
3 correction pulses
are needed
Mode = 1 (fast correction)
Offset value = Eppm / 4.069
3.600
4 correction pulses
are needed
aaa-004375
Fig 9.
PCA85073A
Product data sheet
Offset calibration calculation workflow
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Automotive Real-Time Clock/calendar with alarm function and I2C-bus
(2)
(1)
(3)
-6
-4
-2
0
deviation after
correction in
MODE = 1
-1.628 ppm
2
4
6
8
10
12
deviation after
correction in
MODE = 0
+1.628 ppm
14
16
measured/calculated
deviation 14.648 ppm
aaa-004371
With the offset calibration an accuracy of 2 ppm (0.5 offset per LSB) can be reached (see
Table 12).
1 ppm corresponds to a time deviation of 0.0864 seconds per day.
(1) 3 correction pulses in MODE = 0 correspond to 13.02 ppm.
(2) 4 correction pulses in MODE = 1 correspond to 16.276 ppm.
(3) Reachable accuracy zone.
Fig 10. Result of offset calibration
7.2.4 Register RAM_byte
The PCA85073A provides a free RAM byte, which can be used for any purpose, for
example, status byte of the system.
Table 17.
RAM_byte - 8-bit RAM register (address 03h) bit description
Bit
Symbol
Value
7 to 0
B[7:0]
00000000[1] to RAM content
11111111
[1]
Description
Default value.
7.3 Time and date registers
Most of the registers are coded in the BCD format to simplify application use.
7.3.1 Register Seconds
Table 18.
Seconds - seconds register (address 04h) bit description
Bit
Symbol
7
OS
6 to 4
[1]
PCA85073A
Product data sheet
Place value Description
0
-
clock integrity is guaranteed
1[1]
-
clock integrity is not
guaranteed; oscillator has
stopped or has been
interrupted
0[1] to 5
ten’s place
0[1]
unit place
oscillator stop
SECONDS
3 to 0
Value
to 9
actual seconds coded in BCD
format, see Table 19
Default value.
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Automotive Real-Time Clock/calendar with alarm function and I2C-bus
Table 19.
Seconds value in
decimal
Upper-digit (ten’s place)
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
00[1]
0
0
0
0
0
0
0
01
0
0
0
0
0
0
1
02
0
0
0
0
0
1
0
Digit (unit place)
:
:
:
:
:
:
:
:
09
0
0
0
1
0
0
1
10
0
0
1
0
0
0
0
:
:
:
:
:
:
:
:
58
1
0
1
1
0
0
0
59
1
0
1
1
0
0
1
[1]
7.3.1.1
Seconds coded in BCD format
Default value.
OS: Oscillator stop
When the oscillator of the PCA85073A is stopped, the OS flag is set. The oscillator can be
stopped, for example, by connecting one of the oscillator pins OSCI or OSCO to ground.
The oscillator is considered to be stopped during the time between power-on and stable
crystal resonance. This time can be in the range of 200 ms to 2 s depending on crystal
type, temperature, and supply voltage.
The flag remains set until cleared by command (see Figure 11). If the flag cannot be
cleared, then the oscillator is not running. This method can be used to monitor the
oscillator and to determine if the supply voltage has reduced to the point where oscillation
fails.
OS = 1 and flag can not be cleared
OS = 1 and flag can be cleared
VDD
oscillation
OS flag set when
oscillation stops
OS flag
OS flag cleared
by software
t
oscillation now stable
aaa-004420
Fig 11. OS flag
PCA85073A
Product data sheet
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Automotive Real-Time Clock/calendar with alarm function and I2C-bus
7.3.2 Register Minutes
Table 20.
Bit
Minutes - minutes register (address 05h) bit description
Symbol
Value
7
-
0
-
unused
6 to 4
MINUTES
0[1] to 5
ten’s place
0[1]
unit place
actual minutes coded in BCD
format
3 to 0
[1]
to 9
Place value Description
Default value.
7.3.3 Register Hours
Table 21.
Hours - hours register (address 06h) bit description
Bit
Symbol
Value
Place value Description
7 to 6
-
00
-
12-hour
mode[1]
5
AMPM
0[2]
-
AM
1
-
PM
4
unused
AM/PM indicator
HOURS
3 to 0
0[2]
to 1
ten’s place
0[2]
to 9
unit place
actual hours in 12-hour mode
coded in BCD format
24-hour mode[1]
5 to 4
HOURS
3 to 0
0[2] to 2
ten’s place
0[2]
unit place
to 9
[1]
Hour mode is set by the 12_24 bit in register Control_1.
[2]
Default value.
actual hours in 24-hour mode
coded in BCD format
7.3.4 Register Days
Table 22.
Days - days register (address 07h) bit description
Bit
Symbol
Value
Place value Description
7 to 6
-
00
-
unused
5 to 4
DAYS[1]
0[2]
to 3
ten’s place
actual day coded in BCD format
0[3]
to 9
unit place
3 to 0
[1]
If the year counter contains a value, which is exactly divisible by 4 (including the year 00), the PCA85073A
compensates for leap years by adding a 29th day to February.
[2]
Default value.
[3]
Default value is 1.
7.3.5 Register Weekdays
Table 23.
PCA85073A
Product data sheet
Weekdays - weekdays register (address 08h) bit description
Bit
Symbol
Value
Description
7 to 3
-
00000
unused
2 to 0
WEEKDAYS
0 to 6
actual weekday values, see Table 24
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Automotive Real-Time Clock/calendar with alarm function and I2C-bus
Table 24.
Weekday assignments
Day[1]
Bit
2
1
0
Sunday
0
0
0
Monday
0
0
1
Tuesday
0
1
0
Wednesday
0
1
1
Thursday
1
0
0
Friday
1
0
1
Saturday[2]
1
1
0
[1]
Definition may be reassigned by the user.
[2]
Default value.
7.3.6 Register Months
Table 25.
Months - months register (address 09h) bit description
Bit
Symbol
Value
Place value Description
7 to 5
-
000
-
unused
4
MONTHS
0 to 1
ten’s place
0 to 9
unit place
actual month coded in BCD
format, see Table 26
3 to 0
Table 26.
Month assignments in BCD format
Month
Product data sheet
Digit (unit place)
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
January[1]
0
0
0
0
1
February
0
0
0
1
0
March
0
0
0
1
1
April
0
0
1
0
0
May
0
0
1
0
1
June
0
0
1
1
0
July
0
0
1
1
1
August
0
1
0
0
0
September
0
1
0
0
1
October
1
0
0
0
0
November
1
0
0
0
1
December
1
0
0
1
0
[1]
PCA85073A
Upper-digit
(ten’s place)
Default value.
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Automotive Real-Time Clock/calendar with alarm function and I2C-bus
7.3.7 Register Years
Table 27.
Bit
7 to 4
Years - years register (0Ah) bit description
Symbol
Value
Place value Description
YEARS
0[1]
ten’s place
[1]
to 9
0[1] to 9
3 to 0
actual year coded in BCD format
unit place
Default value.
7.4 Setting and reading the time
Figure 12 shows the data flow and data dependencies starting from the 1 Hz clock tick.
1 Hz tick
SECONDS
MINUTES
12_24 hour mode
HOURS
LEAP YEAR
CALCULATION
DAYS
WEEKDAY
MONTHS
YEARS
aaa-004421
Fig 12. Data flow for the time function
During read/write operations, the time counting circuits (memory locations 04h through
0Ah) are blocked.
The blocking prevents
• Faulty reading of the clock and calendar during a carry condition
• Incrementing the time registers during the read cycle
After this read/write access is completed, the time circuit is released again and any
pending request to increment the time counters that occurred during the read/write access
is serviced. A maximum of 1 request can be stored; therefore, all accesses must be
completed within 1 second (see Figure 13).
PCA85073A
Product data sheet
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Automotive Real-Time Clock/calendar with alarm function and I2C-bus
t 1[1]
4096
1⁄
8192
1⁄
4096
64
1⁄
128
1⁄
64
1
1⁄
64
1⁄
64
1⁄
60
1⁄
64
1⁄
64
[1]
PCA85073A
Product data sheet
INT period (s)
T = loaded countdown value. Timer stops when T = 0.
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Automotive Real-Time Clock/calendar with alarm function and I2C-bus
8. Characteristics of the I2C-bus interface
The I2C-bus is for bidirectional, two-line communication between different ICs or modules.
The two lines are a Serial DAta line (SDA) and a Serial CLock line (SCL). Both lines must
be connected to a positive supply via a pull-up resistor. Data transfer may be initiated only
when the bus is not busy.
8.1 Bit transfer
One data bit is transferred during each clock pulse. The data on the SDA line must remain
stable during the HIGH period of the clock pulse, as changes in the data line at this time
are interpreted as a control signal (see Figure 16).
SDA
SCL
data line
stable;
data valid
change
of data
allowed
mbc621
Fig 16. Bit transfer
8.2 START and STOP conditions
Both data and clock lines remain HIGH when the bus is not busy.
A HIGH-to-LOW transition of the data line while the clock is HIGH is defined as the START
condition - S.
A LOW-to-HIGH transition of the data line while the clock is HIGH is defined as the STOP
condition - P (see Figure 17).
SDA
SDA
SCL
SCL
S
P
START condition
STOP condition
mbc622
Fig 17. Definition of START and STOP conditions
8.3 System configuration
A device generating a message is a transmitter; a device receiving a message is a
receiver. The device that controls the message is the master; and the devices which are
controlled by the master are the slaves (see Figure 18).
PCA85073A
Product data sheet
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Automotive Real-Time Clock/calendar with alarm function and I2C-bus
MASTER
TRANSMITTER/
RECEIVER
SLAVE
TRANSMITTER/
RECEIVER
SLAVE
RECEIVER
MASTER
TRANSMITTER/
RECEIVER
MASTER
TRANSMITTER
SDA
SCL
mga807
Fig 18. System configuration
8.4 Acknowledge
The number of data bytes transferred between the START and STOP conditions from
transmitter to receiver is unlimited. Each byte of 8 bits is followed by an acknowledge
cycle.
• A slave receiver, which is addressed, must generate an acknowledge after the
reception of each byte
• Also a master receiver must generate an acknowledge after the reception of each
byte that has been clocked out of the slave transmitter
• The device that acknowledges must pull-down the SDA line during the acknowledge
clock pulse, so that the SDA line is stable LOW during the HIGH period of the
acknowledge related clock pulse (set-up and hold times must be considered)
• A master receiver must signal an end of data to the transmitter by not generating an
acknowledge on the last byte that has been clocked out of the slave. In this event, the
transmitter must leave the data line HIGH to enable the master to generate a STOP
condition
Acknowledgement on the I2C-bus is shown in Figure 19.
data output
by transmitter
not acknowledge
data output
by receiver
acknowledge
SCL from
master
1
2
8
9
S
START
condition
clock pulse for
acknowledgement
mbc602
Fig 19. Acknowledgement on the I2C-bus
PCA85073A
Product data sheet
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Automotive Real-Time Clock/calendar with alarm function and I2C-bus
8.5 I2C-bus protocol
8.5.1 Addressing
One I2C-bus slave address (1010001) is reserved for the PCA85073A. The entire I2C-bus
slave address byte is shown in Table 38.
Table 38.
I2C slave address byte
Slave address
Bit
7
6
5
4
3
2
1
MSB
0
LSB
1
0
1
0
0
0
1
R/W
After a START condition, the I2C slave address has to be sent to the PCA85073A device.
The R/W bit defines the direction of the following single or multiple byte data transfer
(R/W = 0 for writing, R/W = 1 for reading). For the format and the timing of the START
condition (S), the STOP condition (P) and the acknowledge bit (A) refer to the I2C-bus
characteristics (see Ref. 12 “UM10204”). In the write mode, a data transfer is terminated
by sending either the STOP condition or the START condition of the next data transfer.
8.5.2 Clock and calendar READ or WRITE cycles
The I2C-bus configuration for the different PCA85073A READ and WRITE cycles is
shown in Figure 20 and Figure 21. The register address is a 5-bit value that defines which
register is to be accessed next. The upper 3 bits of the register address are not used.
acknowledge
from PCA85073A
S
1
0
1
0
0
0
slave address
1
0
write bit
acknowledge
from PCA85073A
acknowledge
from PCA85073A
A
A
A
register address
00h to 11h
0 to n
data bytes
P/S
START/
STOP
aaa-034552
Fig 20. Master transmits to slave receiver (WRITE mode)
PCA85073A
Product data sheet
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Automotive Real-Time Clock/calendar with alarm function and I2C-bus
acknowledge
from PCA85073A
S
1
0
1
0
0
0
1
slave address
0
acknowledge
from PCA85073A
A
write bit
A
register address
00h to 11h
acknowledge
from PCA85073A
S
1
0
1
0
0
slave address
0
1
1
read bit
A
set register
address
P
STOP
acknowledge
from master
no acknowledge
A
A
DATA BYTE
LAST DATA BYTE
read register
data
P
0 to n data bytes
auto increment
memory register address
auto increment
memory register address
aaa-034553
For multimaster configurations and to fasten the communication, the STOP-START sequence can be replaced by a repeated
START (Sr).
Fig 21. Master reads after setting register address (write register address; READ data)
8.5.3 I2C-bus error recovery technique
Slave devices like the PCA85073A use a state machine to implement the I2C protocol and
expect a certain sequence of events to occur to function properly. Unexpected events at
the I2C master can wreak havoc with the slaves connected on the bus. However, it is
usually possible to recover deterministically to a known bus state with careful protocol
manipulation.
A deterministic method to clear this situation if SDA is stuck LOW (it effectively blocks any
other I2C-bus transaction, once the master recognizes a ‘stuck bus’ state), is for the
master to blindly transmit nine clocks on SCL. If the slave was transmitting data or
acknowledging, nine or more clocks ensures the slave state machine returns to a known,
idle state since the protocol calls for eight data bits and one ACK bit. It does not matter
when the slave state machine finishes its transmission; extra clocks are recognized as
STOP conditions.
With careful design of the bus master error recovery firmware, many I2C-bus protocol
problems can be avoided.
S/W considerations: NXP recommends customers allow for S/W reset capability to enable
the bus error recovery technique. The 9-clock pulse method as described above involves
a bus-master capable of providing such a signal.
Further comments/additional information are available in Ref. 13 “UM10301” and Ref. 12
“UM10204”.
PCA85073A
Product data sheet
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Automotive Real-Time Clock/calendar with alarm function and I2C-bus
9. Internal circuitry
PCA85073A
VDD
OSCI
CLKOUT
OSCO
SCL
INT
SDA
VSS
aaa-034551
Fig 22. Device diode protection diagram of PCA85073A
10. Safety notes
CAUTION
This device is sensitive to ElectroStatic Discharge (ESD). Observe precautions for handling
electrostatic sensitive devices.
Such precautions are described in the ANSI/ESD S20.20, IEC/ST 61340-5, JESD625-A or
equivalent standards.
PCA85073A
Product data sheet
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Automotive Real-Time Clock/calendar with alarm function and I2C-bus
11. Limiting values
Table 39. Limiting values[1]
In accordance with the Absolute Maximum Rating System (IEC 60134).
Symbol
Parameter
Conditions
Min
VDD
supply voltage
0.5
+6.5
V
IDD
supply current
50
+50
mA
VI
input voltage
0.5
+6.5
V
VO
output voltage
0.5
+6.5
V
on pins SCL, SDA, OSCI
Max
Unit
II
input current
at any input
10
+10
mA
IO
output current
at any output
10
+10
mA
Ptot
total power dissipation
-
300
mW
65
+150
C
40
+105
C
Tstg
storage temperature
Tamb
ambient temperature
[2]
operating device
[1]
Remark: The PCA85073A part is not guaranteed (nor characterized) above the operating range as denoted in the datasheet. NXP
recommends not to bias the PCA85073A device during reflow (e.g. if utilizing a 'coin' type battery in the assembly). If customer so
chooses to continue to use this assembly method, there must be the allowance for a full `0 V' level Power supply `reset' to re-enable the
device. Without a proper POR, the device may remain in an indeterminate state.
[2]
According to the store and transport requirements (see Ref. 14 “UM10569”) the devices have to be stored at a temperature of +8 C to
+45 C and a humidity of 25 % to 75 %.
PCA85073A
Product data sheet
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Automotive Real-Time Clock/calendar with alarm function and I2C-bus
12. Characteristics
Table 40. Static characteristics
VDD = 0.9 V to 5.5 V; VSS = 0 V; Tamb = 40 C to +105 C; fosc = 32.768 kHz; quartz Rs = 60 k; CL = 7 pF; unless otherwise
specified.
Symbol
Parameter
Conditions
Min
Typ
Max
Unit
supply voltage
interface inactive; fSCL = 0 Hz
[1]
0.9
-
5.5
V
interface active; fSCL = 400 kHz
[1]
1.8
-
5.5
V
CLKOUT disabled;
VDD = 5 V
[2]
Tamb = 25 C
-
250
450
nA
Tamb = 85 C
-
550
750
nA
Tamb = 105 C
-
900
1800
nA
interface active;
fSCL = 400 kHz
-
35
50
A
Supplies
VDD
IDD
supply current
interface inactive; fSCL = 0 Hz
Inputs[3]
VI
input voltage
VSS
-
5.5
V
VIL
LOW-level input
voltage
VSS
-
0.3VDD
V
VIH
HIGH-level input
voltage
0.7VDD
-
VDD
V
ILI
input leakage current
-
0
-
A
0.15
-
+0.15
A
-
-
7
pF
VI = VSS or VDD
post ESD event
Ci
[4]
input capacitance
Outputs
VOH
HIGH-level output
voltage
on pin CLKOUT
0.8VDD
-
VDD
V
VOL
LOW-level output
voltage
on pins SDA, INT, CLKOUT
VSS
-
0.2VDD
V
IOH
HIGH-level output
current
output source current;
VOH = 4.6 V;
VDD = 5 V;
on pin CLKOUT
1
3
-
mA
IOL
LOW-level output
current
output sink current; VOL = 0.4 V;
VDD = 5 V
PCA85073A
Product data sheet
on pin SDA
3
8.5
-
mA
on pin INT
2
6
-
mA
on pin CLKOUT
1
3
-
mA
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PCA85073A
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Automotive Real-Time Clock/calendar with alarm function and I2C-bus
Table 40. Static characteristics …continued
VDD = 0.9 V to 5.5 V; VSS = 0 V; Tamb = 40 C to +105 C; fosc = 32.768 kHz; quartz Rs = 60 k; CL = 7 pF; unless otherwise
specified.
Symbol
Parameter
Conditions
Min
Typ
Max
Unit
fosc/fosc
relative oscillator
frequency variation
VDD = 200 mV; Tamb = 25 C
-
0.075
-
ppm
CL(itg)
integrated load
capacitance
on pins OSCO, OSCI
Oscillator
[5]
CL = 7 pF
4.2
7
9.8
pF
CL = 12.5 pF
7.5
12.5
17.5
pF
-
-
100
k
series resistance
Rs
[1]
For reliable oscillator start-up at power-on use VDD greater than 1.2 V. If powered up at 0.9 V the oscillator will start but it might be a bit
slow, especially if at high temperature. Normally the power supply is not 0.9 V at start-up and only comes at the end of battery
discharge. VDD min of 0.9 V is specified so that the customer can calculate how large a battery or capacitor they need for their
application. VDD min of 1.2 V or greater is needed to ensure speedy oscillator start-up time. For a restart condition, NXP recommends a
full '0 V' VDD value upon re-biasing.
[2]
Timer source clock = 1⁄60 Hz, level of pins SCL and SDA is VDD or VSS.
[3]
The I2C-bus interface of PCA85073A is 5 V tolerant.
[4]
Implicit by design.
[5]
Integrated load capacitance, CL(itg), is a calculation of COSCI and COSCO in series: C L itg = -------------------------------------------- .
C OSCI C OSCO
C OSCI + C OSCO
aaa-005740
50
IDD
(μA)
40
30
(1)
20
(2)
10
0
0
100
200
300
400
fSCL (kHz)
500
Tamb = 25 C; CLKOUT disabled.
(1) VDD = 5.0 V.
(2) VDD = 3.3 V.
Fig 23. Typical IDD with respect to fSCL
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Automotive Real-Time Clock/calendar with alarm function and I2C-bus
aaa-017376
1200
IDD
(nA)
1000
800
(1)
(2)
600
400
200
0
-50
-10
30
70
Tamb (ºC)
110
CL(itg) = 7 pF; CLKOUT disabled.
(1) VDD = 5.5 V.
(2) VDD = 3.3 V.
aaa-017381
1200
IDD
(nA)
1000
800
(1)
(2)
600
400
200
0
-50
-10
30
70
Tamb (ºC)
110
CL(itg) = 12.5 pF; CLKOUT disabled.
(1) VDD = 5.5 V.
(2) VDD = 3.3 V.
Fig 24. Typical IDD as a function of temperature
PCA85073A
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Automotive Real-Time Clock/calendar with alarm function and I2C-bus
aaa-005739
12
IDD
(μA)
10
(1)
(2)
8
(1)
6
(2)
4
2
0
0
1
2
3
4
5
VDD (V)
6
Tamb = 25 C; fCLKOUT = 32768 Hz.
(1) 47 pF CLKOUT load.
(2) 22 pF CLKOUT load.
aaa-005741
500
IDD
(nA)
400
300
(1)
(2)
200
100
0
0
1
2
3
4
5
VDD (V)
6
Tamb = 25 C; CLKOUT disabled.
(1) CL(itg) = 12.5 pF.
(2) CL(itg) = 7 pF.
Fig 25. Typical IDD with respect to VDD
PCA85073A
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PCA85073A
NXP Semiconductors
Automotive Real-Time Clock/calendar with alarm function and I2C-bus
aaa-005841
800
IDD
(nA)
(1)
600
(2)
400
(3)
(4)
200
0
20
30
40
50
60
70
80
90
RS (kΩ)
100
VDD = 5 V; CLKOUT disabled.
(1) CL(itg) = 12.5 pF; 50 C; maximum value.
(2) CL(itg) = 7 pF; 50 C; maximum value.
(3) CL(itg) = 12.5 pF; 25 C; typical value.
(4) CL(itg) = 7 pF; 25 C; typical value.
Fig 26. IDD with respect to quartz RS
aaa-005743
3
Δfosc
(ppm)
1.5
0
(1)
(2)
-1.5
-3
0
1
2
3
4
5
VDD (V)
6
Tamb = 40 C to +105 C.
(1) CL(itg) = 7 pF.
(2) CL(itg) = 12.5 pF.
Fig 27. Oscillator frequency variation with respect to VDD
PCA85073A
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PCA85073A
NXP Semiconductors
Automotive Real-Time Clock/calendar with alarm function and I2C-bus
Table 41. I2C-bus characteristics
VDD = 1.8 V to 5.5 V; VSS = 0 V; Tamb = 40 C to +105 C; fosc = 32.768 kHz; quartz Rs = 60 k; CL = 7 pF; unless otherwise
specified. All timing values are valid within the operating supply voltage and temperature range and referenced to VIL and VIH
with an input voltage swing of VSS to VDD[1].
Symbol
Parameter
Cb
capacitive load for
each bus line
fSCL
SCL clock frequency
tHD;STA
Conditions
Min
Max
Unit
-
400
pF
0
400
kHz
hold time (repeated)
START condition
0.6
-
s
tSU;STA
set-up time for a
repeated START
condition
0.6
-
s
tLOW
LOW period of the
SCL clock
1.3
-
s
tHIGH
HIGH period of the
SCL clock
0.6
-
s
tr
rise time of both SDA
and SCL signals
20
300
ns
tf
fall time of both SDA
and SCL signals
20 (VDD / 5.5 V) 300
ns
tBUF
bus free time between
a STOP and START
condition
1.3
-
s
tSU;DAT
data set-up time
100
-
ns
tHD;DAT
data hold time
0
-
ns
tSU;STO
set-up time for STOP
condition
0.6
-
s
tVD;DAT
data valid time
0
0.9
s
tVD;ACK
data valid
acknowledge time
0
0.9
s
tSP
pulse width of spikes
that must be
suppressed by the
input filter
0
50
ns
[2]
[3][4]
[1]
A detailed description of the I2C-bus specification is given in Ref. 12 “UM10204”.
[2]
I2C-bus access time between two STARTs or between a START and a STOP condition to this device must be less than one second.
[3]
A device must internally provide a hold time of at least 300 ns for the SDA signal (with respect to the VIH(min) of the SCL signal) to bridge
the undefined region of the falling edge of SCL.
[4]
The maximum tf for the SDA and SCL bus lines is specified at 300 ns. The maximum fall time for the SDA output stage tf is specified at
250 ns. This allows series protection resistors to be connected in between the SDA and the SCL pins and the SDA/SCL bus lines
without exceeding the maximum specified tf.
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Automotive Real-Time Clock/calendar with alarm function and I2C-bus
protocol
START
condition
(S)
bit 7
MSB
(A7)
tSU;STA
tLOW
bit 6
(A6)
tHIGH
1/f
bit 0
(R/W)
acknowledge
(A)
STOP
condition
(P)
SCL
SCL
tBUF
tr
tf
SDA
tHD;STA
tSU;DAT
tHD;DAT
tVD;DAT
tVD;ACK
tSU;STO
013aaa417
Fig 28. I2C-bus timing diagram; rise and fall times refer to 30 % and 70 %
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Automotive Real-Time Clock/calendar with alarm function and I2C-bus
13. Application information
VDD(2)
TP(3)
SDA
R1(1)
MASTER
TRANSMITTER/
RECEIVER
SCL
1F
100 nF
VDD
CLKOUT
INT
SCL
OSCI
VDD(2)
PCA85073A
OSCO
SDA
R
VSS
R
R: pull-up resistor
R=
SDA SCL
(I2C-bus)
tr
Cb
aaa-032103
A 1 farad super capacitor combined with a low VF diode can be used as a standby or back-up
supply. With the RTC in its minimum power configuration that is, timer off and CLKOUT off, the
RTC may operate for weeks.
(1) R1 limits the inrush current to the super capacitor at power-on.
(2) NXP recommends tying VDD of the device and VDD of all the external pull-up resistors to the same
Power Supply.
(3) NXP also recommends the customer place accessible 'Pads/TP-test point' on the layout so as to
enable a 'hard'' grounding of the power supply VDD in the event a full discharge cannot be attained.
Fig 29. Application diagram for PCA85073A
14. Test information
14.1 Quality information
This product has been qualified in accordance with the Automotive Electronics Council
(AEC) standard Q100 - Failure mechanism based stress test qualification for integrated
circuits, and is suitable for use in automotive applications.
PCA85073A
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Automotive Real-Time Clock/calendar with alarm function and I2C-bus
15. Package outline
TSSOP8: plastic thin shrink small outline package; 8 leads; body width 3 mm
D
E
SOT505-1
A
X
c
y
HE
v M A
Z
5
8
A2
pin 1 index
(A3)
A1
A
θ
Lp
L
1
4
detail X
e
w M
bp
0
2.5
5 mm
scale
DIMENSIONS (mm are the original dimensions)
UNIT
A
max.
A1
A2
A3
bp
c
D(1)
E(2)
e
HE
L
Lp
v
w
y
Z(1)
θ
mm
1.1
0.15
0.05
0.95
0.80
0.25
0.45
0.25
0.28
0.15
3.1
2.9
3.1
2.9
0.65
5.1
4.7
0.94
0.7
0.4
0.1
0.1
0.1
0.70
0.35
6°
0°
Notes
1. Plastic or metal protrusions of 0.15 mm maximum per side are not included.
2. Plastic or metal protrusions of 0.25 mm maximum per side are not included.
OUTLINE
VERSION
REFERENCES
IEC
JEDEC
JEITA
EUROPEAN
PROJECTION
ISSUE DATE
99-04-09
03-02-18
SOT505-1
Fig 30. Package outline SOT505-1 (TSSOP8)
PCA85073A
Product data sheet
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PCA85073A
NXP Semiconductors
Automotive Real-Time Clock/calendar with alarm function and I2C-bus
16. Handling information
All input and output pins are protected against ElectroStatic Discharge (ESD) under
normal handling. When handling Metal-Oxide Semiconductor (MOS) devices ensure that
all normal precautions are taken as described in JESD625-A, IEC 61340-5 or equivalent
standards.
17. Packing information
17.1 Tape and reel information
For tape and reel packing information, please see Ref. 11 “SOT505-1_118”.
PCA85073A
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Automotive Real-Time Clock/calendar with alarm function and I2C-bus
18. Soldering of SMD packages
This text provides a very brief insight into a complex technology. A more in-depth account
of soldering ICs can be found in Application Note AN10365 “Surface mount reflow
soldering description”.
18.1 Introduction to soldering
Soldering is one of the most common methods through which packages are attached to
Printed Circuit Boards (PCBs), to form electrical circuits. The soldered joint provides both
the mechanical and the electrical connection. There is no single soldering method that is
ideal for all IC packages. Wave soldering is often preferred when through-hole and
Surface Mount Devices (SMDs) are mixed on one printed wiring board; however, it is not
suitable for fine pitch SMDs. Reflow soldering is ideal for the small pitches and high
densities that come with increased miniaturization.
18.2 Wave and reflow soldering
Wave soldering is a joining technology in which the joints are made by solder coming from
a standing wave of liquid solder. The wave soldering process is suitable for the following:
• Through-hole components
• Leaded or leadless SMDs, which are glued to the surface of the printed circuit board
Not all SMDs can be wave soldered. Packages with solder balls, and some leadless
packages which have solder lands underneath the body, cannot be wave soldered. Also,
leaded SMDs with leads having a pitch smaller than ~0.6 mm cannot be wave soldered,
due to an increased probability of bridging.
The reflow soldering process involves applying solder paste to a board, followed by
component placement and exposure to a temperature profile. Leaded packages,
packages with solder balls, and leadless packages are all reflow solderable.
Key characteristics in both wave and reflow soldering are:
•
•
•
•
•
•
Board specifications, including the board finish, solder masks and vias
Package footprints, including solder thieves and orientation
The moisture sensitivity level of the packages
Package placement
Inspection and repair
Lead-free soldering versus SnPb soldering
18.3 Wave soldering
Key characteristics in wave soldering are:
• Process issues, such as application of adhesive and flux, clinching of leads, board
transport, the solder wave parameters, and the time during which components are
exposed to the wave
• Solder bath specifications, including temperature and impurities
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Automotive Real-Time Clock/calendar with alarm function and I2C-bus
18.4 Reflow soldering
Key characteristics in reflow soldering are:
• Lead-free versus SnPb soldering; note that a lead-free reflow process usually leads to
higher minimum peak temperatures (see Figure 31) than a SnPb process, thus
reducing the process window
• Solder paste printing issues including smearing, release, and adjusting the process
window for a mix of large and small components on one board
• Reflow temperature profile; this profile includes preheat, reflow (in which the board is
heated to the peak temperature) and cooling down. It is imperative that the peak
temperature is high enough for the solder to make reliable solder joints (a solder paste
characteristic). In addition, the peak temperature must be low enough that the
packages and/or boards are not damaged. The peak temperature of the package
depends on package thickness and volume and is classified in accordance with
Table 42 and 43
Table 42.
SnPb eutectic process (from J-STD-020D)
Package thickness (mm)
Package reflow temperature (C)
Volume (mm3)
< 350
350
< 2.5
235
220
2.5
220
220
Table 43.
Lead-free process (from J-STD-020D)
Package thickness (mm)
Package reflow temperature (C)
Volume (mm3)
< 350
350 to 2000
> 2000
< 1.6
260
260
260
1.6 to 2.5
260
250
245
> 2.5
250
245
245
Moisture sensitivity precautions, as indicated on the packing, must be respected at all
times.
Studies have shown that small packages reach higher temperatures during reflow
soldering, see Figure 31.
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PCA85073A
NXP Semiconductors
Automotive Real-Time Clock/calendar with alarm function and I2C-bus
maximum peak temperature
= MSL limit, damage level
temperature
minimum peak temperature
= minimum soldering temperature
peak
temperature
time
001aac844
MSL: Moisture Sensitivity Level
Fig 31. Temperature profiles for large and small components
For further information on temperature profiles, refer to Application Note AN10365
“Surface mount reflow soldering description”.
19. Footprint information
3.600
2.950
0.125
0.725
0.125
5.750
3.600
3.200
5.500
1.150
0.600
0.450
0.650
solder lands
occupied area
sot505-1_fr
Dimensions in mm
Fig 32. Footprint information for reflow soldering of SOT505-1 (TSSOP8)
PCA85073A
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xxxxxxxxxxxxxxxxxxxxx xxxxxxxxxxxxxxxxxxxxxxxxxx xxxxxxx x x x xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx xxxxxxxxxxxxxxxxxxx xx xx xxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxx xxxxxxxxxxxxxxxxxxx xxxxxx xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx xxxxxxxxxxxx x x
xxxxxxxxxxxxxxxxxxxxx xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx xxxxx xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx xxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxx xxxxxxxxxxxxxxxxxxxx xxx
NXP Semiconductors
PCA85073A
Product data sheet
20. Appendix
20.1 Real-Time Clock selection
Table 44.
Selection of Real-Time Clocks
Alarm, Timer, Interrupt Interface IDD,
Battery Timestamp,
Watchdog
output
typical (nA) backup tamper input
Rev. 1 — 4 October 2019
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AEC-Q100
compliant
Special features
Packages
PCF85063TP
-
1
I2C
220
-
-
-
basic functions only, no
alarm
HXSON8
PCF85063A
X
1
I2C
220
-
-
-
tiny package
SO8, DFN2626-10,
TSSOP8
PCF85063B
X
1
SPI
220
-
-
-
tiny package
DFN2626-10
230
X
X
-
time stamp, battery
backup, stopwatch 1⁄100 s
SO8, TSSOP10,
TSSOP8,
DFN2626-10
X
2
PCF85363A
X
2
I2C
230
X
X
-
time stamp, battery
backup, stopwatch 1⁄100s,
64 Byte RAM
TSSOP10, TSSOP8,
DFN2626-10
PCF2123
X
1
SPI
100
-
-
-
lowest power 100 nA in
operation
TSSOP14, HVQFN16
PCF8523
X
2
I2C
150
X
-
-
lowest power 150 nA in
operation, FM+ 1 MHz
SO8, HVSON8,
TSSOP14, WLCSP
PCF8563
X
1
I2C
250
-
-
-
-
SO8, TSSOP8,
HVSON10
PCA8565
X
1
I2C
600
-
-
grade 1
high robustness,
Tamb40 C to 125 C
TSSOP8, HVSON10
PCA8565A
X
1
I2C
600
-
-
-
integrated oscillator caps,
Tamb40 C to 125 C
WLCSP
PCF8564A
X
1
I2C
250
-
-
-
integrated oscillator caps
WLCSP
PCF2127
X
1
I2C and
SPI
500
X
X
-
temperature
SO16
compensated, quartz built
in, calibrated, 512 Byte
RAM
PCF2127A
X
1
I2C and
SPI
500
X
X
-
temperature
SO20
compensated, quartz built
in, calibrated, 512 Byte
RAM
PCA85073A
51 of 58
© NXP B.V. 2019. All rights reserved.
PCF85263A
I2C
Automotive Real-Time Clock/calendar with alarm function and I2C-bus
Type name
Selection of Real-Time Clocks …continued
Type name
Alarm, Timer, Interrupt Interface IDD,
Battery Timestamp,
Watchdog
output
typical (nA) backup tamper input
Special features
PCF2129
X
1
I2C and
SPI
500
X
PCF2129A
X
1
I2C and
SPI
500
PCA2129
X
1
I2C and
SPI
PCA21125
X
1
SPI
Packages
X
-
temperature
SO16
compensated, quartz built
in, calibrated
X
X
-
temperature
SO20
compensated, quartz built
in, calibrated
500
X
X
grade 3
temperature
SO16
compensated, quartz built
in, calibrated
820
-
-
grade 1
high robustness,
Tamb40 C to 125 C
TSSOP14
PCA85073A
52 of 58
© NXP B.V. 2019. All rights reserved.
Automotive Real-Time Clock/calendar with alarm function and I2C-bus
Rev. 1 — 4 October 2019
All information provided in this document is subject to legal disclaimers.
AEC-Q100
compliant
NXP Semiconductors
PCA85073A
Product data sheet
Table 44.
xxxxxxxxxxxxxxxxxxxxx xxxxxxxxxxxxxxxxxxxxxxxxxx xxxxxxx x x x xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx xxxxxxxxxxxxxxxxxxx xx xx xxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxx xxxxxxxxxxxxxxxxxxx xxxxxx xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx xxxxxxxxxxxx x x
xxxxxxxxxxxxxxxxxxxxx xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx xxxxx xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx xxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxx xxxxxxxxxxxxxxxxxxxx xxx
PCA85073A
NXP Semiconductors
Automotive Real-Time Clock/calendar with alarm function and I2C-bus
21. Abbreviations
Table 45.
PCA85073A
Product data sheet
Abbreviations
Acronym
Description
BCD
Binary Coded Decimal
CMOS
Complementary Metal Oxide Semiconductor
ESD
ElectroStatic Discharge
HBM
Human Body Model
I2C
Inter-Integrated Circuit
IC
Integrated Circuit
LSB
Least Significant Bit
MSB
Most Significant Bit
MSL
Moisture Sensitivity Level
PCB
Printed-Circuit Board
POR
Power-On Reset
RTC
Real-Time Clock
SCL
Serial CLock line
SDA
Serial DAta line
SMD
Surface Mount Device
All information provided in this document is subject to legal disclaimers.
Rev. 1 — 4 October 2019
© NXP B.V. 2019. All rights reserved.
53 of 58
PCA85073A
NXP Semiconductors
Automotive Real-Time Clock/calendar with alarm function and I2C-bus
22. References
[1]
AN10365 — Surface mount reflow soldering description
[2]
AN10366 — HVQFN application information
[3]
AN11247 — Improved timekeeping accuracy with PCF85063, PCF8523 and
PCF2123 using an external temperature sensor
[4]
IEC 60134 — Rating systems for electronic tubes and valves and analogous
semiconductor devices
[5]
IEC 61340-5 — Protection of electronic devices from electrostatic phenomena
[6]
IPC/JEDEC J-STD-020 — Moisture/Reflow Sensitivity Classification for
Nonhermetic Solid State Surface Mount Devices
[7]
JESD22-A114 — Electrostatic Discharge (ESD) Sensitivity Testing Human Body
Model (HBM)
[8]
JESD22-C101 — Field-Induced Charged-Device Model Test Method for
Electrostatic-Discharge-Withstand Thresholds of Microelectronic Components
[9]
JESD78 — IC Latch-Up Test
[10] JESD625-A — Requirements for Handling Electrostatic-Discharge-Sensitive
(ESDS) Devices
[11] SOT505-1_118 — TSSOP8; Reel pack; SMD, 13", packing information
[12] UM10204 — I2C-bus specification and user manual
[13] UM10301 — User Manual for NXP Real Time Clocks PCF85x3, PCA8565 and
PCF2123, PCA2125
[14] UM10569 — Store and transport requirements
[15] UM10788 — User manual for I2C-bus RTC demo board OM13515
PCA85073A
Product data sheet
All information provided in this document is subject to legal disclaimers.
Rev. 1 — 4 October 2019
© NXP B.V. 2019. All rights reserved.
54 of 58
PCA85073A
NXP Semiconductors
Automotive Real-Time Clock/calendar with alarm function and I2C-bus
23. Revision history
Table 46.
Revision history
Document ID
Release date
Data sheet status
Change notice
Supersedes
PCA85073A v.1
20191004
Product data sheet
-
-
PCA85073A
Product data sheet
All information provided in this document is subject to legal disclaimers.
Rev. 1 — 4 October 2019
© NXP B.V. 2019. All rights reserved.
55 of 58
PCA85073A
NXP Semiconductors
Automotive Real-Time Clock/calendar with alarm function and I2C-bus
24. Legal information
24.1 Data sheet status
Document status[1][2]
Product status[3]
Definition
Objective [short] data sheet
Development
This document contains data from the objective specification for product development.
Preliminary [short] data sheet
Qualification
This document contains data from the preliminary specification.
Product [short] data sheet
Production
This document contains the product specification.
[1]
Please consult the most recently issued document before initiating or completing a design.
[2]
The term ‘short data sheet’ is explained in section “Definitions”.
[3]
The product status of device(s) described in this document may have changed since this document was published and may differ in case of multiple devices. The latest product status
information is available on the Internet at URL http://www.nxp.com.
24.2 Definitions
Draft — The document is a draft version only. The content is still under
internal review and subject to formal approval, which may result in
modifications or additions. NXP Semiconductors does not give any
representations or warranties as to the accuracy or completeness of
information included herein and shall have no liability for the consequences of
use of such information.
Short data sheet — A short data sheet is an extract from a full data sheet
with the same product type number(s) and title. A short data sheet is intended
for quick reference only and should not be relied upon to contain detailed and
full information. For detailed and full information see the relevant full data
sheet, which is available on request via the local NXP Semiconductors sales
office. In case of any inconsistency or conflict with the short data sheet, the
full data sheet shall prevail.
Product specification — The information and data provided in a Product
data sheet shall define the specification of the product as agreed between
NXP Semiconductors and its customer, unless NXP Semiconductors and
customer have explicitly agreed otherwise in writing. In no event however,
shall an agreement be valid in which the NXP Semiconductors product is
deemed to offer functions and qualities beyond those described in the
Product data sheet.
24.3 Disclaimers
Limited warranty and liability — Information in this document is believed to
be accurate and reliable. However, NXP Semiconductors does not give any
representations or warranties, expressed or implied, as to the accuracy or
completeness of such information and shall have no liability for the
consequences of use of such information. NXP Semiconductors takes no
responsibility for the content in this document if provided by an information
source outside of NXP Semiconductors.
In no event shall NXP Semiconductors be liable for any indirect, incidental,
punitive, special or consequential damages (including - without limitation - lost
profits, lost savings, business interruption, costs related to the removal or
replacement of any products or rework charges) whether or not such
damages are based on tort (including negligence), warranty, breach of
contract or any other legal theory.
Notwithstanding any damages that customer might incur for any reason
whatsoever, NXP Semiconductors’ aggregate and cumulative liability towards
customer for the products described herein shall be limited in accordance
with the Terms and conditions of commercial sale of NXP Semiconductors.
Right to make changes — NXP Semiconductors reserves the right to make
changes to information published in this document, including without
limitation specifications and product descriptions, at any time and without
notice. This document supersedes and replaces all information supplied prior
to the publication hereof.
PCA85073A
Product data sheet
Suitability for use in automotive applications — This NXP
Semiconductors product has been qualified for use in automotive
applications. Unless otherwise agreed in writing, the product is not designed,
authorized or warranted to be suitable for use in life support, life-critical or
safety-critical systems or equipment, nor in applications where failure or
malfunction of an NXP Semiconductors product can reasonably be expected
to result in personal injury, death or severe property or environmental
damage. NXP Semiconductors and its suppliers accept no liability for
inclusion and/or use of NXP Semiconductors products in such equipment or
applications and therefore such inclusion and/or use is at the customer's own
risk.
Applications — Applications that are described herein for any of these
products are for illustrative purposes only. NXP Semiconductors makes no
representation or warranty that such applications will be suitable for the
specified use without further testing or modification.
Customers are responsible for the design and operation of their applications
and products using NXP Semiconductors products, and NXP Semiconductors
accepts no liability for any assistance with applications or customer product
design. It is customer’s sole responsibility to determine whether the NXP
Semiconductors product is suitable and fit for the customer’s applications and
products planned, as well as for the planned application and use of
customer’s third party customer(s). Customers should provide appropriate
design and operating safeguards to minimize the risks associated with their
applications and products.
NXP Semiconductors does not accept any liability related to any default,
damage, costs or problem which is based on any weakness or default in the
customer’s applications or products, or the application or use by customer’s
third party customer(s). Customer is responsible for doing all necessary
testing for the customer’s applications and products using NXP
Semiconductors products in order to avoid a default of the applications and
the products or of the application or use by customer’s third party
customer(s). NXP does not accept any liability in this respect.
Limiting values — Stress above one or more limiting values (as defined in
the Absolute Maximum Ratings System of IEC 60134) will cause permanent
damage to the device. Limiting values are stress ratings only and (proper)
operation of the device at these or any other conditions above those given in
the Recommended operating conditions section (if present) or the
Characteristics sections of this document is not warranted. Constant or
repeated exposure to limiting values will permanently and irreversibly affect
the quality and reliability of the device.
Terms and conditions of commercial sale — NXP Semiconductors
products are sold subject to the general terms and conditions of commercial
sale, as published at http://www.nxp.com/profile/terms, unless otherwise
agreed in a valid written individual agreement. In case an individual
agreement is concluded only the terms and conditions of the respective
agreement shall apply. NXP Semiconductors hereby expressly objects to
applying the customer’s general terms and conditions with regard to the
purchase of NXP Semiconductors products by customer.
All information provided in this document is subject to legal disclaimers.
Rev. 1 — 4 October 2019
© NXP B.V. 2019. All rights reserved.
56 of 58
PCA85073A
NXP Semiconductors
Automotive Real-Time Clock/calendar with alarm function and I2C-bus
No offer to sell or license — Nothing in this document may be interpreted or
construed as an offer to sell products that is open for acceptance or the grant,
conveyance or implication of any license under any copyrights, patents or
other industrial or intellectual property rights.
Translations — A non-English (translated) version of a document is for
reference only. The English version shall prevail in case of any discrepancy
between the translated and English versions.
Export control — This document as well as the item(s) described herein
may be subject to export control regulations. Export might require a prior
authorization from competent authorities.
24.4 Trademarks
Notice: All referenced brands, product names, service names and trademarks
are the property of their respective owners.
I2C-bus — logo is a trademark of NXP B.V.
25. Contact information
For more information, please visit: http://www.nxp.com
For sales office addresses, please send an email to: salesaddresses@nxp.com
PCA85073A
Product data sheet
All information provided in this document is subject to legal disclaimers.
Rev. 1 — 4 October 2019
© NXP B.V. 2019. All rights reserved.
57 of 58
PCA85073A
NXP Semiconductors
Automotive Real-Time Clock/calendar with alarm function and I2C-bus
26. Contents
1
2
3
4
4.1
5
6
6.1
6.2
7
7.1
7.2
7.2.1
7.2.1.1
7.2.1.2
7.2.1.3
7.2.2
7.2.2.1
7.2.2.2
7.2.2.3
7.2.2.4
7.2.3
7.2.3.1
7.2.3.2
7.2.3.3
7.2.4
7.3
7.3.1
7.3.1.1
7.3.2
7.3.3
7.3.4
7.3.5
7.3.6
7.3.7
7.4
7.5
7.5.1
7.5.2
7.5.3
7.5.4
7.5.5
7.5.6
7.6
7.6.1
7.6.2
7.6.3
General description . . . . . . . . . . . . . . . . . . . . . . 1
Features and benefits . . . . . . . . . . . . . . . . . . . . 1
Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Ordering information . . . . . . . . . . . . . . . . . . . . . 2
Ordering options . . . . . . . . . . . . . . . . . . . . . . . . 2
Block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Pinning information . . . . . . . . . . . . . . . . . . . . . . 4
Pinning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Pin description . . . . . . . . . . . . . . . . . . . . . . . . . 4
Functional description . . . . . . . . . . . . . . . . . . . 5
Registers organization . . . . . . . . . . . . . . . . . . . 6
Control registers . . . . . . . . . . . . . . . . . . . . . . . . 7
Register Control_1 . . . . . . . . . . . . . . . . . . . . . . 7
EXT_TEST: external clock test mode . . . . . . . . 8
STOP: STOP bit function . . . . . . . . . . . . . . . . . 9
Software reset . . . . . . . . . . . . . . . . . . . . . . . . 11
Register Control_2 . . . . . . . . . . . . . . . . . . . . . 12
Alarm interrupt . . . . . . . . . . . . . . . . . . . . . . . . 13
MI and HMI: minute and half minute interrupt. 14
TF: timer flag . . . . . . . . . . . . . . . . . . . . . . . . . 14
COF[2:0]: Clock output frequency . . . . . . . . . 15
Register Offset . . . . . . . . . . . . . . . . . . . . . . . . 16
Correction when MODE = 0 . . . . . . . . . . . . . . 17
Correction when MODE = 1 . . . . . . . . . . . . . . 18
Offset calibration workflow . . . . . . . . . . . . . . . 19
Register RAM_byte . . . . . . . . . . . . . . . . . . . . 20
Time and date registers . . . . . . . . . . . . . . . . . 20
Register Seconds . . . . . . . . . . . . . . . . . . . . . . 20
OS: Oscillator stop . . . . . . . . . . . . . . . . . . . . . 21
Register Minutes. . . . . . . . . . . . . . . . . . . . . . . 22
Register Hours . . . . . . . . . . . . . . . . . . . . . . . . 22
Register Days . . . . . . . . . . . . . . . . . . . . . . . . . 22
Register Weekdays. . . . . . . . . . . . . . . . . . . . . 22
Register Months . . . . . . . . . . . . . . . . . . . . . . . 23
Register Years . . . . . . . . . . . . . . . . . . . . . . . . 24
Setting and reading the time. . . . . . . . . . . . . . 24
Alarm registers . . . . . . . . . . . . . . . . . . . . . . . . 25
Register Second_alarm . . . . . . . . . . . . . . . . . 25
Register Minute_alarm . . . . . . . . . . . . . . . . . . 26
Register Hour_alarm . . . . . . . . . . . . . . . . . . . 26
Register Day_alarm . . . . . . . . . . . . . . . . . . . . 26
Register Weekday_alarm . . . . . . . . . . . . . . . . 27
Alarm function. . . . . . . . . . . . . . . . . . . . . . . . . 27
Timer registers . . . . . . . . . . . . . . . . . . . . . . . . 28
Register Timer_value . . . . . . . . . . . . . . . . . . . 28
Register Timer_mode . . . . . . . . . . . . . . . . . . . 29
Timer functions . . . . . . . . . . . . . . . . . . . . . . . . 29
7.6.3.1
8
8.1
8.2
8.3
8.4
8.5
8.5.1
8.5.2
8.5.3
9
10
11
12
13
14
14.1
15
16
17
17.1
18
18.1
18.2
18.3
18.4
19
20
20.1
21
22
23
24
24.1
24.2
24.3
24.4
25
26
Countdown timer interrupts . . . . . . . . . . . . . .
Characteristics of the I2C-bus interface . . . .
Bit transfer . . . . . . . . . . . . . . . . . . . . . . . . . . .
START and STOP conditions. . . . . . . . . . . . .
System configuration . . . . . . . . . . . . . . . . . . .
Acknowledge . . . . . . . . . . . . . . . . . . . . . . . . .
I2C-bus protocol . . . . . . . . . . . . . . . . . . . . . . .
Addressing . . . . . . . . . . . . . . . . . . . . . . . . . . .
Clock and calendar READ or WRITE cycles .
I2C-bus error recovery technique . . . . . . . . . .
Internal circuitry . . . . . . . . . . . . . . . . . . . . . . .
Safety notes. . . . . . . . . . . . . . . . . . . . . . . . . . .
Limiting values . . . . . . . . . . . . . . . . . . . . . . . .
Characteristics . . . . . . . . . . . . . . . . . . . . . . . .
Application information . . . . . . . . . . . . . . . . .
Test information . . . . . . . . . . . . . . . . . . . . . . .
Quality information . . . . . . . . . . . . . . . . . . . . .
Package outline. . . . . . . . . . . . . . . . . . . . . . . .
Handling information . . . . . . . . . . . . . . . . . . .
Packing information . . . . . . . . . . . . . . . . . . . .
Tape and reel information . . . . . . . . . . . . . . .
Soldering of SMD packages. . . . . . . . . . . . . .
Introduction to soldering. . . . . . . . . . . . . . . . .
Wave and reflow soldering. . . . . . . . . . . . . . .
Wave soldering . . . . . . . . . . . . . . . . . . . . . . .
Reflow soldering . . . . . . . . . . . . . . . . . . . . . .
Footprint information . . . . . . . . . . . . . . . . . . .
Appendix . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Real-Time Clock selection . . . . . . . . . . . . . . .
Abbreviations . . . . . . . . . . . . . . . . . . . . . . . . .
References. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Revision history . . . . . . . . . . . . . . . . . . . . . . .
Legal information . . . . . . . . . . . . . . . . . . . . . .
Data sheet status . . . . . . . . . . . . . . . . . . . . . .
Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . .
Disclaimers . . . . . . . . . . . . . . . . . . . . . . . . . .
Trademarks . . . . . . . . . . . . . . . . . . . . . . . . . .
Contact information . . . . . . . . . . . . . . . . . . . .
Contents. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
31
32
32
32
32
33
34
34
34
35
36
36
37
38
45
45
45
46
47
47
47
48
48
48
48
49
50
51
51
53
54
55
56
56
56
56
57
57
58
Please be aware that important notices concerning this document and the product(s)
described herein, have been included in section ‘Legal information’.
© NXP B.V. 2019.
All rights reserved.
For more information, please visit: http://www.nxp.com
For sales office addresses, please send an email to: salesaddresses@nxp.com
Date of release: 4 October 2019
Document identifier: PCA85073A
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