ADPD107 TIA mode Individual gain setting and: output data is strange.

Hi,

I'm trying TIA mode individual gain setting and measuring when PD output current is 0uA (connecting Photo Diode but no light)

Settings outline is following,

SLOTA ch1: 25k  ch2: 200k  

SLOTB off

ADC OFFSET: ch1:0  ch2: 0

LED off

(discribe this "setting1")

but output value is strange like fllowings:

1. ch2 output is always 0. 

 

2. ch1 output is different from that of setting2: (SLOTA ch1: 25k  ch2: 25k

    output was about 3600 when setting 1 but over 4000 when setting2.

    I tried several times but the result was same.) 

according to formula(11), in any gain settings, output values must be about 3100.

I mean that PD current calculation formula (11) of each channel is affected by the other channel's gain setting. why? 

here, output of ch1 and ch2 when setting1

and setting2

the register settings are followings

(address 1byte and value 2bytes. Formart is like your .dcfg file)

00 0800
01 00FF
02 0005
06 0700
09 00C8
10 0000
11 3019
12 0140
14 0555
15 0000
18 0000
19 0000
1A 0000
1B 0000
1E 0000
1F 0000
20 0000
21 0000
22 1030
23 1032
24 3032
25 0440
30 0719
31 0113 
34 0300
35 0719
36 1013
38 0000
39 2140
3B 2140
3C 3006
42 1CFB
43 AE65
44 1CFB
45 AE65
4B 269A
4D 005E
4E 0040
4F 20D0
50 0040
54 0020
55 030C  // setting2: 030F
58 0000
5A 0000
5F 0000

best,



fixed typo
[edited by: kodama.kcc at 2:41 AM (GMT 0) on 9 Jan 2019]