E629AXF View Datasheet(PDF) - Semtech Corporation
Part Name
Description
MFG CO.
'E629AXF' PDF : 16 Pages View PDF
Edge629
TEST AND MEASUREMENT PRODUCTS
Circuit Description
Introduction
Coarse Delay
The Edge629 is a quad channel delay element with 2
basic operating modes:
1) Fanout – 1 signal in, 4 signals out
2) Pass Through – 4 signals in, 4 signals out
In all modes, each channel supports 3 delay functions:
1) Coarse timing delay
2) Fine timing delay
3) Falling edge adjust
All 3 delay functions are independent of each other, and
independent for each channel.
The programming of the delay functions is done using a
16 bit register, loaded serially, which contains both a de-
lay and an address value.
Coarse propagation delay adjustment is accomplished
using a series of gate delays and multiplexers (see Fig-
ure 1). Coarse delay provides a total delay span of:
1 Coarse LSB = 90 ps
2 Coarse LSB = 180 ps
4 Coarse LSB = 360 ps
8 Coarse LSB = 720 ps
16 Coarse LSB = 1.44 ns
32 Coarse LSB = 2.88 ns
0 ns ≤ Coarse Delay Range ≤ 5.67 ns
Each channel has its own unique coarse delay setting and
may be programmed independently from all other chan-
nels. The coarse delay of any channel will not affect the
fine delay of that channel, nor will it affect the overall
delay of any other channel.
The propagation delay of a rising edge and falling edge
will track each other over the entire coarse delay span.
(Adding or subtracting coarse delay does not cause pulse
width distortion.)
Delay Code
000000
111111
Minimum Delay
Maximum Delay
0.0 ns
5.67 ns
90 ps
180 ps
360 ps
720 ps
1.44 ns
2.88 ns
LSB
MSB Coarse Delay Register
16 Bit Serial Register
Figure 1. Coarse Delay Architecture
2005 Semtech Corp. Rev. 3, 8/1/05
4
www.semtech.com
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