07 | Keysight | U4164A Logic Analyzer Module - Data Sheet
Dual-Sample State Mode
Dual-sample mode has multiple benefits:
1. For non-DDR or LPDDR memory trace capture, dual-sample state mode allows
acquisition of state (synchronous) data at rates up to 4 Gb/s depending on the speed
state option purchased. When used in this mode, the data will appear in two labels. One
label for rising edge and another for falling edge captures. The logic analyzer will be
clocked with one edge of the system clock. Labels can be merged using the Keysight
B4602A signal extractor tool. When operated in dual-sample state mode on all pods,
the channel count is 68 channels for one U4164A 136 channels for two U4164As, or 204
channels for three U4164A modules combined. Dual-sample state mode can be selected
on a per-pod-pair basis, so if you have only a subset of signals that require dual-sample
mode, the channel count can be higher.
2. For DDR/LPDDR memory signals up to 2.5 Gb/s, dual-sample state mode allows
separation of read data samples from write data samples. The B4661A DDR2/3/4
decoder or the B4661A LPDDR/2/3/4 decoder reassembles the data to align with
the associated commands. (There’s no need for the B4602A tool for DDR and LPDDR
solutions.)
3. For DDR4 and LPDDR4 memory solutions over 2.5 Gb/s using dual-sample state mode,
double probing is required to capture read and write DQ signals and dual-sample state
mode is used to capture rising and falling edge DQ samples. Using this technique, a
maximum of 34 DDR4 or LPDDR4 DQ signals operating over 2.5 Gb/s can be captured
per U4164A module. Address, command, and control signals for DDR or LPDDR memory
do not require double probing above or below 2.5 Gb/s data rates, so modules with a
mixture of address, command and DQ signals may have higher signal count depending
on how the signals are routed into the U4164A.
Quad-Sample State Mode
Quad-sample state mode enables four samples with two different threshold settings from
a single-touch connection to high-speed data signals under test. This results in four unique
sample positions at two unique thresholds. Single-touch connection preserves probe routing
space and minimized probe load on high-speed digital systems. DDR4 and LPDDR4 probing for
data rates over 2.5 Gb/s are examples of where single-touch probing enables high-speed trace
capture using quad-sample mode to capture read and write DQ (data) at different thresholds
with rising and falling edge samples for both read and write data to sample, trigger, and display
DDR4 and LPDDR4 at data rates up to 4 Gb/s.
When operated in quad-sample state mode on all pods, the channel count is 34 channels
for one U4164A, 68 channels for two U4164As, or 102 channels for three U4164A modules
combined. Quad-sample state mode is only available with U4164A Option -02G. Quad-sample
state mode can be selected on a per-pod-pair basis, so if you have only a subset of signals that
require quad-sample mode, the channel count can be higher.
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