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Vcm output current?

Category: Hardware
Product Number: LTC2387-18

I have a LTC2387-18 ADC being driven by a signal chain with two AD8139 differential amps in series.  The LTC2387-18 provides Vcm to each AD8139 to set the common mode.

In testing, the LTC2387-18 gives good results with its inputs isolated from the driver and tied to Vcm.  It gives good results when driven by the AD8139 (with it's inputs tied to Vcm.

When I add the next op-amp in the chain, the other AD8139, the FFT results now show an area of concern around 1MHz.

I believe I have good supplies and good coupling.  I'm just working through ideas now, one of them being Vcm.  I want to make sure Vcm from the LTC2387-18 can drive two AD8139 Vcm inputs.  I'm sure it can as that draw is only 9uA max.  I've made a few passes through the LTC-2387-18 datasheet and don't see the current in a table or a graph.