Elm Electronics – Circuits for the Hobbyist

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ELM624

Electrical Characteristics

Absolute Maximum Ratings

Storage Temperature....................... -65°C to +150°C

Ambient Temperature with

Power Applied....................................-40°C to +85°C

Voltage on any other pin with

Note:

Stresses beyond those listed here will likely damage

the device. These values are given as a design

guideline only. The ability to operate to these levels

is neither inferred nor recommended.

3 of 7

All values are for operation at 25°C and a 5V supply, unless otherwise noted. For further information, refer to note 1 below.

Characteristic

Minimum

Typical

Maximum

Conditions

Units

4.5

5.0

5.5

V

0.05

V/ms

1.0

2.4

mA

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.

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. Device only. Does not include any load currents.

4. The value of the internal pullup resistance is both supply and temperature dependent.

5. This specification represents the current flowing through the protection diodes when applying large voltages

to the Rx input (pin 5) through a current limiting resistance. Currents quoted are the maximum continuous.

6. Nominal data transfer rate. Assumes that a 3.58 MHz crystal is used as a frequency reference. Data is

transferred to and from the ELM624 with 8 data bits, no parity, and 1 stop bit (8 N 1).

Input low voltage

V

Input high voltage

V

Output low voltage

0.6

V

Output high voltage

V

Current (sink) = 8.7mA

Current (source) = 5.4mA

see note 2

ELM624DSB

Internal pullup resistances

(see note 4)

500

K

Ω

300

600

Pin 4 (reset)

see note 3

Rx pin input current

mA

see note 5

-0.5

Pin 7 (LANC)

K

Ω

30

20

50

RS232 Baud Rate

baud

see note 6

9600

+0.5