Real time clock module
Block diagram
Overview
• Interface type
I
2
C-Bus interface Fast-Mode 400 kHz
• High stability
XS : ±3.0 x 10
-6
/ -40 ºC to +85 ºC (Monthly rate: ±8 seconds)
: ±5.0 x 10
-6
/ +85 ºC to +105 ºC (Monthly rate: ±13.2 seconds)
XB : ±5.0 x 10
-6
/ -40 ºC to +85 ºC (Monthly rate: ±13.2 seconds)
: ±8.0 x 10
-6
/ +85 ºC to +105 ºC (Monthly rate: ±21 seconds)
• Time stamp function
Trigger source:
External event (EVIN) input, voltage drop/oscillation
stop status detected, command input from the host
Record data:
1/1024 seconds to 1 second, seconds, minutes, hours,
days, months, years
Number of recordable events:
Maximum 32 events
• Backup power supply switching function
The V
DD and VBAT voltages are monitored to switch between Normal
mode (V
DD operation) and Backup mode (VBAT operation).
• Clock output (FOUT)
Selectable from 32.768 kHz, 1024 Hz and 1 Hz outputs
Output can be controlled by a register or FOE input (selectable
with a register).
Terminal connection / External dimensions (Unit: mm)
Specifications (characteristics)
∗ Refer to application manual for details
Recommended Operating Conditions
Item
Symbol
Condition
Min.
Typ.
Max.
unit
Operating voltage
V
DD
-
1.6
3.0
5.5
V
Clock supply voltage
VCLK
-
1.1
3.0
5.5
V
Operating Temperature
Ta
-
-40
+25
+105
ºC
V
DD
detection voltage
-V
DET1
V
DD
, Fall
1.35
1.45
1.55
V
Frequency Characteristics
Item
Symbol
Condition
Min.
Typ.
Max.
unit
Frequency
tolerance
∆ f / f
XS
T
a
= -40 to +85 °C
-3
-
+3
× 10
−6
T
a
= +85 to +105 °C
-5
-
+5
XB
T
a
= -40 to +85 °C
-5
-
+5
T
a
= +85 to +105 °C
-8
-
+8
start-up time
t
STA
T
a
= +25 °C,
V
DD
= 1.6 V ∼ 5.5 V
-
0.5
1.0
s
Current consumption
T
a
= -40 °C to +105 °C
Item
Symbol
Condition
Min.
Typ.
Max.
unit
I
DD
I
BAT
V
BAT
= 3.0 V,
/INT= Hi-Z, FOUT: Output OFF (Hi
-Z),
Temperature compensation interval: 2 s,
FSEL1= FSEL0 = 1, INIEN = 1,
CHGEN = 0, SCL = SDA = L
-
240
1500
nA
I
32k
V
DD
= 3.0 V,
/INT= Hi-Z, F O UT: 32 kHz output, C
L
= 0 pF,
Temperature compensation interval: 2 s,
FSEL1 = FSEL0 = 1, INIEN = 1,
CHGEN = 0, SCL = SDA = H
-
1.0
3.0
µA
Option
I/F
Option
EVIN pin
Number
/INTpin
Number
FOUT
Number of time stamps recorded
by EVIN pin trigge
FIFO Mode
Direct Mode
I
2
C
A
2
1
Yes
32 times
22 times
B
3
1
-
32times
32 times
REAL TIME CLOCK MODULE (I
2
C-Bus)
Built-in 32.768 kHz-DTCXO, +105°C operating temperature,
Low current consumption, Built-in power supply switching circuit and
Time stamp function up to 32 records
RX8901CE
• Built in frequency adjusted 32.768 kHz crystal unit and DTCXO
• Interface Type : I
2
C-Bus
•Current consumption : 240 nA / 3 V (Typ.)
•Auto power switching function : Automatically switches to backup power supply
by monitoring the V
DD / VBAT voltage
• Time stamp function : Maximum 32 time stamps
• Interrupt output : Wake up every hour or every minute or every second
• Alarm interruption : Day, date, hour, minute, second
• Auto repeat wakeup timer interruption
• Self-monitoring interruption : Crystal oscillation stop, V
BAT
low, V
DD
low
Signal Name
I / O Function
EVIN1,2,3 Input
External event input pins. Detectable even in Backup mode.
Pull-up and pull-down is configurable by the resisters
SCL
Input
Serial clock input pin
SDA
Input /
Output
Serial data input and output pin
FOUT Output
Frequency output pin (CMOS). 32.768 kHz (default), 1024 Hz or
1 Hz clock output is selectable. This pin can be switched to the
wakeup timer interrupt output (CMOS)
/INT Output
Interrupt output pin (N-ch. open drain). The wakeup timer, time
update, alarm, and/or event detection interrupt signals can be
selected to output from this pin. When two or more signals are
selected, they are NORed before being output.
This pin is effective even in Backup mode.
VDD
-
Power-supply pin
VOUT -
Internal operating voltage output pin
Connect a 1 µF bypass capacitor to this pin
VBAT -
Backup power supply pin
Connect a backup power supply such as a large-size capacitor,
secondary battery, or primary battery.
The operating power voltage is supplied from this pin to the internal
circuits in Backup mode.
GND
-
Ground pin
RX8901CE
( 3.2 × 2.5 mm, t = 1.0 mm Max. )
Product Number (2,000 pcs / Reel)
RX8901CE XS A0
：
X1B000481000115
RX8901CE XB A0
：
X1B000481000215
RX8901CE XS B0
：
X1B000481000315
RX8901CE XB B0
：
X1B000481000415
Pin
Connection
Option A
Option B
1
V
DD
2
V
OUT
3
V
BAT
4
FOUT
EVIN3
5
SCL
6
EVIN
1
7
SDA
8
/INT
9
GND
10
EVIN2
Real time clock module
Product name
RX8901CE XS A0
① ② ③
① Model CE type package 3.2 x 2.5 x 1.0 mm
② Frequency tolerance
XS: ±3.0 x 10
-6
/ -40 ºC to +85 ºC (Monthly rate: ±8 seconds)
±5.0 x 10
-6
/ +85 ºC to +105 ºC (Monthly rate: ±13.2 seconds)
XB: ±5.0 x 10
-6
/ -40 ºC to +85 ºC (Monthly rate: ±13.2 seconds)
±8.0 x 10
-6
/ +85 ºC to +105 ºC (Monthly rate: ±21 seconds)
③ Pin Option
A: Option A
B: Option B