DLPS206 May 2021 DLPC7540
PRODUCTION DATA
The DLPC7540 USB differential interface waveform quality and timing is dependent on the total length of the interconnect system, the spacing between traces, the characteristic impedance, etch losses, and how well matched the lengths are across the interface. Thus, ensuring positive timing margin requires attention to many factors.
DLPC7540 I/O timing parameters, USB transmitter and receiver timing parameters, as well as USB specific timing requirements can be found in their corresponding data sheets. PCB routing mismatch can be budgeted and met through controlled PCB routing. PCB related requirements for USB are provided in Table 10-7 as a starting point for the customer.
PARAMETER | MIN | TYP | MAX | UNIT |
---|---|---|---|---|
Cross-talk between data lane (USB_DAT_P, USB_DAT_N) and other signals | < 1.5 | mVpp | ||
Intra-lane skew (USB_DAT_P, USB_DAT_N) | < 20 | ps | ||
Differential Impedance (USB_DAT_P, USB_DAT_N) | 76.5 | 90 | 103.5 | Ω |
Single Mode impedance (USB_DAT_P, USB_DAT_N) | 45 | Ω | ||
Common Mode Impedance (USB_DAT_P, USB_DAT_N) | 21 | 30 | 39 | Ω |
Parasitic resistance (USB_DAT_P, USB_DAT_N) | ≤ 0.5 | Ω | ||
Total capacitance (USB_DAT_P, USB_DAT_N) | < 4 | pF | ||
Differences of trace capacitance between USB_DAT_P, USB_DAT_N | < 1 | pF | ||
TXRTUNE resistor | 172.26 | 174 | 175.74 | Ω |
Additional layout guidelines for USB_DAT_P/USB_DAT_N:
Additional USB layout guidelines for TXRTUNE