Underflow during Ioutfs Calibration

Question

First off, there's a copy+paste error from ad9106's datasheet. From step 1 of Ioutfs calibration: 
 
 1. Set the calibration ranges in Register 0x008 [7:0] and 
 Register 0x0D[5:4] to their minimum values to allow best calibration. 
 
 For the AD9102, only bits 0 and 1 are valid. 
 I'm getting stuck on step 8 of the calibration sequence: 
 
 8. After calibration, verify that the overflow and underflow 
 flags in Register 0x0D are not set (Bits[14:8]). If they are 
 set, change the corresponding calibration range to the next 
 larger range and start from Step 5 again. 
 
 I am getting underflow for GAIN_CAL (bit 9 of CALCONFIG [0x0D]) 
 I do not see a mention of what the valid range is for gain. (I'm assuming it's in reference to DACRANGE [0x08].) I assigned bits 0 and 1 to be 0. 
 What is the valid range for gain?

Ryan-G · Accepted Answer

Thanks for the response Larry. 
 I actually went back to check the datasheet, and the value of my resistor was too high - producing a current lower than the minimum value allowed. 
 I modified it to a 15k resistor connection, producing a current of about 2.24 mA. 
 After the modification, my calibration sequence completed without error.)

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Underflow during Ioutfs Calibration