ELM634
Absolute Maximum Ratings
Storage Temperature....................... -65°C to +150°C
Ambient Temperature with
Power Applied....................................-40°C to +85°C
Voltage on V
DD
with respect to V
SS
............ 0 to +7.0V
Voltage on any other pin with
respect to V
SS
........................... -0.6V to (V
DD
+ 0.6V)
Note:
Stresses beyond those listed here will likely damage
the device. These values are given as a design
guideline only, and the ability to operate to these
levels is neither inferred nor recommended.
Electrical Characteristics
All values are for operation at 25°C and a 5V supply, unless otherwise noted. For further information, refer to note 1 below.
Characteristic
Supply voltage, V
DD
V
DD
rate of rise
Average supply current, I
DD
Input low voltage
Input high voltage
Output low voltage
Output high voltage
RS232Rx pin input current
RS232 baud rate
Minimum
4.5
0.05
Typical
5.0
Maximum Units
5.5
V
V/ms
Conditions
see note 2
0.8
V
SS
0.85 x V
DD
1.4
0.15 x V
DD
V
DD
0.6
mA
V
V
V
V
Current (sink) = 8.7mA
Current (source) = 5.4mA
see note 3
see note 4
V
DD
- 0.7
-0.5
57600
+0.5
mA
baud
Notes:
1. This integrated circuit is produced with a Microchip Technology Inc.’s PIC12C5XX as the core embedded
microcontroller. For further device specifications, and possibly clarification of those given, please refer to the
appropriate Microchip documentation (available at http://www.microchip.com/).
2. This spec must be met in order to ensure that a correct power on reset occurs. It is quite easily achieved
using most common types of supplies, but may be violated if one uses a slowly varying supply voltage, as
may be obtained through direct connection to solar cells, or some charge pump circuits.
3. This specification represents the current flowing through the internal protection diodes when the voltage
connected to the RS232Rx input (through a current limiting resistance) is greater than V
DD
or less than V
SS
.
Currents quoted are the maximum that should be allowed to flow continuously.
4. Nominal data transfer rate when the recommended 3.58MHz crystal is used as the frequency reference.
Data is transferred to and from the ELM634 with 8 data bits, no parity, and 1 stop bit (8 N 1).
ELM634DSB
Elm Electronics – Circuits for the Hobbyist
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