- RTC Top
- What is RTC Modules?
- Epson's RTC Modules
- Features
- Scenes
- RTC Modules for Automotive
- Development Tools
- Videos
RX8130CE :I2C-Bus Interface Build in backup battery charge control function
- Built in frequency adjusted 32.768 kHz crystal unit
- Interface Type
I2C-Bus interface
- Interface voltage range
1.6V to 5.5V
- Wide voltage for time keeping
1.1V to 5.5V
- Low backup current
300 nA ( Typ. ) / 3 V
- Auto power switching function:Switchover by main power supply monitor.
- Backup battery charge control function: For the rechargeable lithium batteries.
- Reset functions with a delay:Detect a main power supply and remove the reset.
- The various function include full calendar, alarm, timer, etc.
- 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)
Design Support Data Download
Block diagram
Overview
- I2C-Bus interface.
- Auto power switching function
- The VDD voltage is monitored and it switches to the backup power supply by the automatic operation. The switch voltage to the backup power supply. 1.25V (Min.)
- Even if the main power supply voltage is decreased, the current flow from the backup power supply is prevented.
- Charge control function for the rechargeable lithium batteries.
- Stop charging automatically by detecting the full charge.
- Records in the register detecting the backup power supply voltage decrease.
- Reset function with a delay
- When the main power is supplied, reset output is released.The release voltage is selected by the register. (2.80V / 2.75V)
- Delay time from the voltage rise detection is 60ms Typ.
- Frequency output function
- Output frequency is selectable from 32.768kHz, 1024Hz,1Hz.
- Timer function
- Selectable in 1/4096 second from 65535 hours.
- Timer source clock are 1hour, 1min, 64Hz, 4096Hz.
- It is automatically recorded to TF-bit at the time of event occurrence, and possible to output with /IRQ pin.
Specifications (characteristics)
Refer to application manual for details.
Recommended Operating Conditions
Item | Symbol | Conditions | Min. | Typ. | Max. | Unit |
---|---|---|---|---|---|---|
Operating supply voltage | VDD | - | 1.25 | 3.0 | 5.5 | V |
Clock supply voltage | VCLK | - | 1.1 | 3.0 | 5.5 | V |
Operating temperature | TOPR | - | -40 | +25 | +85 | °C |
VDD detect voltage | -VDET2 | VDD,Fall | 1.20 | 1.30 | 1.40 | V |
Frequency characteristics
Item | Symbol | Conditions | Rating | Unit |
---|---|---|---|---|
Frequency tolerance | Δ f / f | Ta = +25 °C VDD = 3.0 V |
B : 5 ± 23* | x 10-6 |
Oscillation start-up time | tSTA | VDD =2.75V to 5.5V | 1 Max. | s |
*Equivalent to ±1 minute of monthly deviation (excluding offset.)
Current consumption characteristics
Item | Symbol | Conditions | Min. | Typ. | Max. | Unit |
---|---|---|---|---|---|---|
Current consumption | IBK | SCL=SDA = "L" , VBAT=3.0V ,VDD=VIO=0.0V |
- | 300 | 500 | nA |
V32K | SCL=SDA = "H" , FOUT=32.768kHz, /IRQ=OFF, VDD=VIO=3.0V, FOUT pin CL=15pF CHGEN=L or VBAT≧VDET3 |
- | 3.5 | 4.0 | µA |
Pin function
Signal Name | I / O | Function |
---|---|---|
SCL | input | Serial clock input pin. |
SDA | Input / Output | Data input and output pin. |
FOUT | Output | Frequency output pin with output control function. (C-MOS)Output frequency can be selected
as 32.768kHz, 1024Hz, 1Hz. |
/ RST | Output | Reset output pin.(N-ch open drain)
In case of VDD voltage drop detection, a reset signal is outputted. In case of VDD voltage rise detection, it is released reset signal after 60ms. |
/ IRQ | Output | Interrupts output by Alarm and Timer events.(N-ch open drain) |
VDD | - | This is a power-supply pin. It can impress the voltage unlike VIO. |
VIO | - | This is a interface power supply pin. This is a pin to supply the voltage same as a host. |
Vout | - | Internal voltage output pin. Connect smoothing capacitor of 1.0µF |
VBAT | - | This is a power supply pin for backup battery.
This is a pin to connect a large-capacity capacitor, a secondary battery,a primary battery. In a backup power supply operating range, the voltage is supplied inside by this pin. |
GND | - | Connected to a ground |
Terminal connection/External dimensions
(Unit: mm)
Footprint (Recommended)
(Unit: mm)
To maintain stable operation, provide a 0.1uF by-pass capacitor
at a location as near as possible to the power source terminal of the crystal product (between Vcc - GND).