RX8900SA :I²C-Bus Interface Real Time Clock Module
(Built-in 32.768 kHz-DTCXO, High Stability and Power Switching)

Built in frequency adjusted 32.768 kHz crystal unit and DTCXO.
Interface Type
I²C-Bus interface (400kHz)
Interface voltage range
2.5V to 5.5V
Temp. compensated voltage range
2.0V to 5.5V
Clock supply voltage range
1.6V to 5.5V
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
https://www5.epsondevice.com/en/information/support/linux_rtc/
The registered trademark Linux® is used pursuant to a sublicense from LMI(Linux Mark Institute)

RX8900SA

Application Manual
(ETM45E-08) (3.0MB)

Design Support Data Download

IBIS Models

Footprint Data

Block diagram

Overview

High Stability
- UA ± 3.4 x 10^-6 / -40 °C to +85 °C ( Equivalent to ±9 seconds of month deviation )
- UB ± 5.0 x 10^-6 / -40 °C to +85 °C ( Equivalent to ±13 seconds of month deviation )
- UC ± 5.0 x 10^-6 / -30 °C to +70 °C ( 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 VDD to backup battery connected to VBAT is possible.
  VDD voltage drop(VDET3) 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)

Specifications (characteristics)

Refer to application manual for details.

Electrical Characteristics

Item	Symbol	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 *3	°C
Stability	Δ f/f	UA	T_a=-40°C to+85°C		±3.4 *1			x10^-6
		UB	T_a=-40°C to+85°C		±5.0 *2
		UC	T_a=-30°C to+70°C		±5.0 *2
Current consumption(1)	l_DD1	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)	l_DD2			V_DD=3V	-	0.70	1.4	µA

*1 Equivalent to ±9 seconds of month deviation.
*2 Equivalent to ±13 seconds of month deviation.
*3 Please contact us about +85°C < T_OPR

32.768 kHz-DTCXO Frequency temperature characteristics (Example)

name

Pin function

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.

Terminal connection/External dimensions

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.

Footprint (Recommended)

footprint