VSP10T21

3-V, 10-BIT, 21-MSPS, ENHANCED TIMING CONTROL

CCD ANALOG FRONT END

SLES027 – MARCH 2002

18

POST OFFICE BOX 655303

PRINCIPLES OF OPERATION

grounding and decoupling

General practices must apply to the printed-circuit board (PCB) design to limit high frequency transients and

noise that are fed back into the supply and reference lines. This requires that the supply and reference terminals

be sufficiently bypassed. In the case of power supply decoupling, 0.1-

µF ceramic chip capacitors are adequate

to keep the impedance low over a wide frequency range. Recommended external decoupling for the three

voltage reference terminals is shown in Figure 4. Since the effectiveness of the decoupling capacitors depends

largely on the proximity to the individual supply terminal, all decoupling capacitors must be placed as close as

Common ground is also recommended.

voltage references

An internal precision voltage reference of 1.5 V nominal is provided. This reference voltage generates the ADC

Ref– voltage of 1 V and Ref+ of 2 V. It also sets the clamp voltage. All internally generated voltages are fixed

values and cannot be adjusted. Terminals 37 (RBD), 38 (RPD), and 39 (RMD) must not be used to drive any

loads.