Data Sheet

HMC974LC3C

Rev. E | Page 9 of 12

THEORY OF OPERATION

The HMC974LC3C is a window comparator where the range of

the window is defined with RT as the top of the voltage window

range and RB as the bottom of the voltage window range. The

comparator has two modes of operation: track mode and latch

mode. While in track mode, the comparator determines three

things:

1.

If the signal is below the window voltage value, RT, and

above the window voltage value, RB, represented by the

WOUTB output.

2.

If the signal is above the window voltage value RT, which is

represented by the ORB output.

3.

If the signal is below the window voltage value RB, which is

represented by the URB output.

A typical 5 Gbps output eye is shown in Figure 12 with specific

details outlined in Table 4.

TIME (33.3ps/DIV)

EDGE SAMPLES

Figure 12. Eye Diagram at 5 Gbps

Table 4. Eye Diagram Details

Parameter

Value

Bit Rate

5 Gbps

Pattern Length

Deterministic Jitter (Peak-to-Peak)

2.15 ps

Vertical Scale

80 mV/div

Time Scale

33.3 ps/div

POWER SEQUENCING

Use the following supplies sequentially to power up the device:

1.

2.

3.

The power-down sequence is the reverse of the previous

sequence:

1.

2.

3.

Apply power to the HMC974LC3C before applying the input

signals (WIN and WIT) and remove the input signals (WIN and

WIT) prior to powering it down.