Datasheet

Actual size
Real time clock module
Real time clock moduleReal time clock module
Real time clock module
Block diagram Overview
SCL
SDA
FOE
FOUT
/I
NT
V
DD
V
BAT
L
VEL SHIFTER
V DD
Detector
GND
Bus
Interface
Register
Control
(System
Control)
Divider Clock
and
Calender
Timer
Register
Interrupts
Controller
Alarm
Register
FOUT
Controller
DTCXO
R
C
secondary
battery
EDLC
or
V BAT
primary
battery
R
C
Battery backup connection example (1)
V BAT
Battery backup connection example (2)
•
••
•
High Stability
•UA ± 3.4 x 10
-6
/ -40 ºC to +85 ºC
( Equivalent to 9 seconds of month deviation )
•UB ± 5.0 x 10
-6
/ -40 ºC to +85 ºC
( Equivalent to 13 seconds of month deviation )
•UC ± 5.0 x 10
-6
/ -30 ºC to +70 ºC
( Equivalent to 13 seconds of month deviation )
• 32.768 kHz frequency output function
• FOUT pin output (C-MOS output), CL=30 pF
• Output selectable: 32.768 kHz, 1024 Hz, 1 Hz
• Available automatic battery backup switch-over function
 Charge from V DD to backup battery connected to V BAT is
possible. V DD voltage drop(V DET3 ) detection and automatically
switches to the backup battery.
This circuit is optimal to backup with a secondary battery and
a large capacitor.
• Timer function
 Timer period is adjustable in 1/4096 second from 4095 minutes.
• Alarm function
 Available dual-alarm, weekly and monthly.
• Temp. sensor function
 Available readout temperature data from embedded temp
sensor. (Bank.2_Add17h)
Pin Function
Terminal connection
/
External dimensions
(
Unit
:mm)
The metal case inside of the molding compound may be exposed on the top or bottom of this product.
This purely cosmetic and does not have any effect on quality, reliability or electrical specs.
Specifications (characteristics)
∗
Refer to
application
manual for details.
REAL TIME CLOCK MODULE (I
2
C-Bus)
Built-in 32.768 kHz-DTCXO, High Stability
and Power Switching
RX 8900 SA / CE
•Built in frequency adjusted 32.768 kHz crystal unit and DTCXO.
•Interface Type : I
2
C-Bus interface (400kHz)
•Interface voltage range : 2.5 V to 5.5 V
•Temp. compensated voltage range : 2.0 V to 5.5 V
•Clock supply voltage range : 1.6 V to 5.5 V
•Selectable clock output (32.768 kHz, 1024 Hz, 1 Hz)
•The various functions include full calendar, alarm, timer, temp. sensor function.
.Epson prepared Linux driver for development.
(http://www5.epsondevice.com/en/information/support/linux_rtc/)
The registered trademark Linux® is used pursuant to a sublicense from LMI(Linux Mark Institute)
The I
2
C-Bus is a trademark of NXP Semiconductors.
Signal Name I / O Function
T1(CE) input
Use by the manufacture for testing.
( Do not connect externally.)
SCL input Serial clock input pin.
FOUT Output
The pin outputs the reference clock signal.
( CMOS output )
V BAT -
Battery supply.
This pin has charge capability to backup battery.
V DD - Connected to a positive power supply
FOE input The input pin for the FOUT output control.
/ INT Output Interrupt output (N-ch. open drain).
GND - Connected to a ground
T2(V PP ) -
Use by the manufacture for testing.
( Do not connect externally.)
SDA I/O Data input and output pin.
 Electrical Characteristics
Item
Symb
ol
Conditions Min. Typ. Max. Unit
Operating voltage V DD
Interface voltage
2.5 3.0 5.5 V
Temp. compensated Voltage V TEM Temp. compensated voltage 2.0 3.0 5.5 V
Clock supply voltage V CLK Internal clock 1.6 3.0 5.5 V
Operating temperature T OPR No condensation
-40 +25 +85
∗
1
ºC
Stability
∆ f / f
UA
Ta = -40 ºC to +85 ºC
±3.4
∗2
× 10
-6
UB
Ta = -40 ºC to +85 ºC
±5.0
∗3
UC
Ta = -30 ºC to +70 ºC
Current consumption (1) I DD 1
fSCL=0Hz, /INT=V DD ,
FOE =GND
V DD =V BAT
FOUT: OFF
Temp. Compensation
interval 2.0 s.
V DD = 5V - 0.72 1.5
µA
Current consumption (2) I DD 2 V DD = 3V - 0.70 1.4
∗1 )
Please contact us about +85 °C < T OPR
∗2 )
Equivalent to 9 seconds of month deviation.
∗3 )
Equivalent to 13 seconds of month deviation.
Product Number (Please contact us)
RX8900SA : X1B000292xxxx00
RX8900CE UA : X1B000301000100
RX8900CE UB : X1B000301000200
RX8900CE UC : X1B000301000300
RX8900SA RX8900CE



32.768 kHz-DTCXO Frequency temperature characteristics (Example)
Frequency temperature characteristics
-30
-25
-20
-15
-10
-5
0
5
10
-45 -35 -25 -15 -5 5 15 25 35 45 55 65 75 85
Temperature (ºC)
Frequency tolerance ( ×10
-
6
)
Tuning fork X'tal
32.768 kHz DTCXO
RX8900CE
1. FOE 10. /INT
2. VDD 9. GND
3. VBAT 8. T2(VPP)
4. FOUT 7. SDA
5. SCL 6. T1(CE)
2.5 ± 0.2
3.2 ± 0.2
1.0Max.
RX8900SA
1. T1(CE)
10.1
±
0.2
5.0
7.4
±
0.2
3.2
±
0.1
1.27
14. N.C.
2. SCL 13. SDA
3. FOUT 12. T2(V PP )
4. N.C. 11. GND
5. V BAT 10.
/ INT
6. V DD 9. N.C.
7. FOE 8. N.C.
SOP − 14 pin
RX8900SA
(10.1 × 7.4 × 3.3 mm)
RX8900CE
(3.2 × 2.5 × 1.0 mm)
CE