AnsweredAssumed Answered

ADN8834 OUT2 oscillation at cooling mode only

Question asked by Terumasa on Mar 2, 2016
Latest reply on Mar 14, 2016 by Terumasa

Hello

 

Our customer will use ADN8834 and evaluating  ADN8834CB-EVALZ.

At initial setting with his laser module including TEC and thermistor, OUT2 is oscillated.

So he aligned the C  and R around OUT2.

As the result of alignment, OUT2 is stable at 25 degreeC and heating mode but OUT2 is oscillated at cooling mode.

I describes below about his alignment.

Please let me know your advice to avoid this problem.

 

About His alignment

 

Temperature condition: 25 degreeC
TEMPSET: fixed 1.544V

His board: ADN8834CB-EVALZ

Change by below method: Cl, Cd, Cf, Rl, Rd, Rp in datasheet P.13 figure 26.

Rl:51kΩ、Rd:100kΩ、Cd:100pF、Rp:100kΩ、Cl:22µF、Cf:0.01µF

 

He aligns as below method.

1:  Short Cl and open Cd  from condition of ADN8834CB-EVALZ.

2: The retio of Rl/Rp is increased and confirm the oscillation of OUT2. Then the retio of Rl/Rp is decreased by a factor of the two.

3: Add Cl and decreas its value until OUT2 starts oscillation. Then he increases Cl by a factor of the two.

4: Short Rd and add Cd. He increases Cd until OUT2 starts oscillation.Then Cd is decreased and Rd is added.

 

Now, OUT2 is oscillated at cooling mode only in above 4.

Please let me know your advice about the problem for above method and avoiding this problem.

 

If you need any other information ,please let me know it.

 

Regards,

Terumasa

Outcomes