SNLS400D January 2012 – January 2015 DS100BR111A
PRODUCTION DATA.
NOTE
Information in the following applications sections is not part of the TI component specification, and TI does not warrant its accuracy or completeness. TI’s customers are responsible for determining suitability of components for their purposes. Customers should validate and test their design implementation to confirm system functionality.
For SAS/SATA systems, a low speed OOB (Out-of-Band) communication sequence is used to detect and communicate device capabilities between host ASIC and link partners. These OOB signals, including COMWAKE, COMINIT, COMRESET, and COMSAS, are a series of burst, idle, and negation times transmitted and detected across the SAS/SATA link. These bursts occur at a rapid rate, with the COMWAKE signal having the most stringent requirement of 106.6 ns active followed by 106.6 ns idle. Normally, if the MODE pin is left floating in Slow OOB mode, the device goes idle-to-active in approximately 150 ns. If the device is set to SAS mode (MODE pin tied via 1 kΩ to VDD (2.5 V mode) or VIN (3.3 V mode)), the device goes idle-to-active in approximately 3 to 4 ns. This fast idle-to-active time is critical to pass OOB signaling, and when operating in pin mode, the MODE pin should be tied high. If operating in SMBus slave mode, the user can set Reg 0x28 to 0x4C for this faster idle-to-active response.
The DS100BR111A works to extend the reach possible by using active equalization on the channel, boosting attenuated signals so that they can be more easily recovered at the Rx endpoint. The capability of the repeater can be explored across a range of data rates and ASIC-to-link-partner signaling, as shown in the following test setup connections. The test setup connections diagrams shown represent typical generic application scenarios for the DS100BR111A.
As with any high speed design, there are many factors that influence the overall performance. Below are a list of critical areas for consideration during design.
The DS100BR111A is designed to be placed at an offset location with respect to the overall channel attenuation. In order to optimize performance, the repeater requires optimization to extend the reach of the cable or trace length while also recovering a solid eye opening. For a generic 10GbE application where link training is not required, the following settings in Table 10 and Table 11 may be referenced as an initial starting point:
CHANNEL SETTINGS | PIN MODE |
---|---|
EQx[1:0] | 0, 0 |
VOD_SEL | 0 |
DEMx | 0 |
CHANNEL SETTINGS | SMBus MODES |
---|---|
EQx | 0x00 |
VODx | 000'b |
DEMx | 000'b |
The SMBus Slave Mode code example in Table 12 may be used to program the DS100BR111A with the recommended device settings.
REGISTER | WRITE VALUE | COMMENTS | ||
---|---|---|---|---|
0x06 | 0x18 | Set SMBus Slave Mode Register Enable. | ||
0x08 | 0x04 | Enable Output Mode Control for individual channel outputs. | ||
0x0F | 0x00 | Set CHA EQ to 0x00. | ||
0x11 | 0x00 | Set CHA DEM to 000'b. | ||
0x16 | 0x00 | Set CHB EQ to 0x00. | ||
0x18 | 0x00 | Set CHB DEM to 000'b. | ||
0x23 | 0x00 | Set CHA VOD to 000'b. | ||
0x28 | 0x00 | Leave Idle Control at default levels. For SAS/SATA applications, set Reg 0x28 to 0x4C. |
||
0x2D | 0xA1 | Set CHB VOD to 000'b. |
Examples of the repeater performance are illustrated in the performance curves in the next section.
The lab setups referenced in Figure 10 to Figure 12 were used to collect typical performance data on FR4 and cable media. For all measurements, Mode Pin = Float.