ZHCSME1C August 2018 – June 2021 DS250DF230
PRODUCTION DATA
A 5-tap DFE can be enabled within the data path of each channel to assist in reducing the effects of crosstalk, reflections, or post-cursor, inter-symbol interference (ISI). The DFE must be manually enabled, regardless of the selected adapt mode. Once the DFE is enabled, it can be configured to adapt only during lock acquisition or to adapt continuously. The DFE can also be manually configured to specified tap polarities and tap weights. However, when the DFE is configured manually, the DFE auto-adaption must be disabled. For many applications with lower insertion loss (that is, < 30 dB) lower crosstalk, and/or lower reflections, part or all of the DFE can be disabled to reduce power consumption. The DFE can either be fully enabled (taps 1-5), partially enabled (taps 1-2 only), or fully disabled (no taps). The DFE taps support continuous adaptation, the device is capable of compensating large channel loss variation over temperature
The DFE taps are all feedback taps with 1UI spacing. Each tap has a specified boost weight range and polarity bit.
DFE PARAMETER | DECIMAL (REGISTER VALUE) | VALUE (mV) (TYP) |
---|---|---|
Tap 1 Weight Range | 0 - 31 | 0 – 217 |
Tap 2-5 Weight Range | 0 - 15 | 0 – 105 |
Tap Weight Step Size | NA | 7 |
Polarity | 0: (+) positive; feedback value creates a low-pass filter response, thus providing attenuation to correct for negative-sign, post-cursor ISI | |
1: (-) negative; Feedback value creates a high-pass filter response, thus providing boost to correct for positive-sign, post-cursor ISI. |