SPRS976E November 2016 – May 2018 DM505
PRODUCTION DATA.
A 1.8-V LVCMOS-Compatible Clock Input can be used instead of the internal oscillator to provide the SYS_CLK2 clock input to the system. The external connections to support this are shown in, Figure 5-17. The xi_osc1 pin is connected to the 1.8-V LVCMOS-Compatible clock sources. The xo_osc1 pin is left unconnected. The vssa_osc1 pin is connected to board ground (VSS).
Table 5-22 summarizes the OSC1 input clock electrical characteristics.
NAME | DESCRIPTION | MIN | TYP | MAX | UNIT |
---|---|---|---|---|---|
f | Frequency | Range from 12 to 38.4 | MHz | ||
CIN | Input capacitance | 2.819 | 3.019 | 3.219 | pF |
IIN | Input current (3.3V mode) | 4 | 6 | 10 | µA |
tsX | Start-up time(1) | See(2) | ms |
Table 5-23 details the OSC1 input clock timing requirements.
NAME | DESCRIPTION | MIN | TYP | MAX | UNIT | ||
---|---|---|---|---|---|---|---|
CK0 | 1 / tc(xiosc1) | Frequency, xi_osc1 | Range from 12 to 38.4 | MHz | |||
CK1 | tw(xiosc1) | Pulse duration, xi_osc1 low or high | 0.45 × tc(xiosc1) | 0.55 × tc(xiosc1) | ns | ||
tj(xiosc1) | Period jitter(1), xi_osc1 | 0.01 × tc(xiosc1)(5) | ns | ||||
tR(xiosc1) | Rise time, xi_osc1 | 5 | ns | ||||
tF(xiosc1) | Fall time, xi_osc1 | 5 | ns | ||||
tj(xiosc1) | Frequency accuracy(4), xi_osc1 | Ethernet not used | ±200 | ppm | |||
Ethernet RGMII using derived clock | ±50 | ppm |
– The maximum value is the difference between the longest measured clock period and the expected clock period
– The minimum value is the difference between the shortest measured clock period and the expected clock period