AMX PTM-D15 User Manual download pdf (Page 100)

MC9S12H256 Device User Guide — V01.18

100

operatingconditionsare less thanworst case or leakage-inducederror is acceptable,largervalues of source

resistance is allowed.

A.2.2.2 Source Capacitance

When sampling an additional internal capacitor is switched to the input. This can cause a voltage drop due

to charge sharing with the external and the pin capacitance. For a maximum sampling error of the input

voltage ≤ 1LSB, then the external filter capacitor, C

≥ 1024 * (C

INS

– C

INN

A.2.2.3 Current Injection

There are two cases to consider.

1. A current is injected into the channel being converted. The channel being stressed has conversion

values of $3FF ($FF in 8-bit mode) for analog inputs greater than V

and $000 for values less than

unless the current is higher than specified as disruptive condition.

2. Current is injected into pins in the neighborhood of the channel being converted. A portion of this

current is picked up by the channel (coupling ratio K), This additional current impacts the accuracy

of the conversion depending on the source resistance.

The additional input voltage error on the converted channel can be calculated as V

ERR

=K*R

INJ

, with I

INJ

being the sum of the currents injected into the two pins adjacent to the converted

channel.

Table A-9 ATD Electrical Characteristics

Conditions are shown in Table A-4 unless otherwise noted

Num C Rating Symbol Min Typ Max Unit

1 C Max input Source Resistance

––1KΩ

Total Input Capacitance

Non Sampling

Sampling

INN

INS

3 C Disruptive Analog Input Current

–2.5 2.5 mA

4 C Coupling Ratio positive current injection

–4

A/A

5 C Coupling Ratio negative current injection

–2

A/A

1 ... 99 100 101 ... 130

Comments to this Manuals

No comments

AMX PTM-D15 User Manual Page 100

Comments to this Manuals

Related products and manuals for TVs & monitors AMX PTM-D15