Техническая Спецификация для Analog Devices AD5560 Evaluation Board EVAL-AD5560EBUZ EVAL-AD5560EBUZ

 

Rev. D | Page 36 of 68 

There are three modes for configuring the force amplifier: safe 
mode, autocompensation mode, and manual compensation mode. 
Manual compensation mode has highest priority, followed by safe 
mode, then autocompensation mode.  

Selected through Compensation Register 1 (see Table 20), this 
mode guarantees stability of the force amplifier under all 
conditions. Where the load is unknown, this mode is useful but 
results in a slow response. This is the power-on default of the 
AD5560.  

Using this mode, the user inputs the C

R

 and ESR values, and  

the AD5560 decides the most appropriate compensation 
scheme for these load conditions. The compensation chosen  
is for an optimum tradeoff between ac response and stability.  

This mode allows access to all of the internal programmable 
parameters to configure poles/zeros, which affect the dynamic 
performance of the loop. These variables are outlined in 
Table 12 and Table 13.  

Figure 57 shows more details of the force amplifier block.  

C

R

 

DUT capacitance with contributing 
ESR 

10 nF 

160 μF 

R

C

 

ESR in series with C

R

 

1 mΩ 

10 Ω 

C

D

 

DUT capacitance with negligible ESR 

100 pF 

10 nF 

R

D

 

Loading resistance at the DUT 

~2 Ω 

Infinity 

I

R

 

Current range 

±5 μA 

±1.2 A 

R

Z

 

Resistor in series with C

C0

, which 

contributes a zero.  

500 Ω 

1.6 MΩ 

R

P

 

Resistor to 8 pF to contribute an 
additional pole 

200 Ω 

1 MΩ 

C

C0

:C

C3

 

Capacitors to ensure 
unconditional stability 

100 pF 

100 nF 

C

F0

:C

F4

 

Capacitors to optimize ac 
performance into different C

R

, C

D

 

4.7 nF 

10 μF 

g

mx

 

Transconductance of force 
amplifier input stage 

40 μA/V 

900 μA/V 

 

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