PTC04

Programmer for Melexis PTC Devices

3901290014501

Page 13 of 15

Data Sheet

Rev 004

December/14

18.

Measurement system

The measurement system on the main board contains mainly a high accurate 16 bit ADC and two 16 to 1

channels MUX. Basically, the ADC always measures differential between inputs.

For the internal voltage channels, the negative input is the internal analog ground.

For the current measurements that use a sense resistor (PPS1-4) are clearly measuring over the sense

resistor.

There are also 4 full differential lines going to the daughter board allowing the user to make high quality

measurements by selecting the reference by the application itself. This way of working easily supports the

use of force and sense lines.

18.1 Channels

Nr.

Pos Input

Neg Input

Description

0

Vout PPS1

Internal AGND

Output Voltage PPS1

1

V driver PPS1

Vout PPS1

Output Current PPS1

2

Vout PPS2

Internal AGND

Output Voltage PPS2

3

V driver PPS2

Vout PPS2

Output Current PPS2

4

Vout PPS3

Internal AGND

Output Voltage PPS3

5

V driver PPS3

Vout PPS3

Output Current PPS3

6

Vout PPS4

Internal AGND

Output Voltage PPS4

7

V driver PPS4

Vout PPS4

Output Current PPS4

8

Supply Driver: +35/2

Internal AGND

Driver Supply divide by 2

9

Supply Analog : +5 V

Internal AGND

Analog 5V Supply

10

Supply Digital : +5 V

Internal AGND

Digital 5V Supply

11

Reference : +2.5V

Internal AGND

Reference Voltage for DAC\ADC

12

DB_Ana_conn Pin 2

DB_Ana_conn Pin 10

Daughterboard Meas. Channel 1

13

DB_Ana_conn Pin 4

DB_Ana_conn Pin 12

Daughterboard Meas. Channel 2

14

DB_Ana_conn Pin 6

DB_Ana_conn Pin 14

Daughterboard Meas. Channel 3

15

DB_Ana_conn Pin 8

DB_Ana_conn Pin 16

Daughterboard Meas. Channel 4

Table 13: ADC measurement channels

18.2 Conversion time

In general the conversion time depends on the loaded firmware version. Theoretically, a full conversion to

a floating real value takes about 4ms if the filter is put at 100 samples.

18.3 Accuracy

To preserve the accuracy of the PTC04, Melexis recommends checking the tolerance of the PTC04 once

a year.