evm629axf Semtech Corporation, evm629axf Datasheet - Page 6

• Manufacturer Part Number: evm629axf
• Description: Timing Deskew Quad Fanout Element
• Manufacturer: Semtech Corporation

Falling Edge Adjustment
The falling edge of a signal may be adjusted to compen-
sate for any system level pulse width distortion that may
occur. Falling edge adjust (FEA) is accomplished using an
analog delay cell and an on-chip 7 bit DAC (see Figure 3).
FEA may be bypassed completely by a multiplexer. Also,
FEA affects only the propagation delay of the falling edge.
It has no effect on the propagation delay of a rising edge.
Each channel has its own unique FEA setting and may be
programmed independently from all other channels. The
FEA of any channel will not affect the propagation delay of
any other channel, nor will FEA affect the propagation delay
of a rising edge.
TEST AND MEASUREMENT PRODUCTS
Circuit Description (continued)
2005 Semtech Corp. Rev. 3, 8/1/05
S
0
1
1
F
E
Figure 3. Falling Edge Adjust Architecture
D
0
1
7 Bit DAC
X
A
0
1
X X
C
0
1
0
1
X X
C
0
1
o
X X
0
1
d
0
1
e
T
F
F
E
a
A
+
–
l l
D
2
n i
2
B
5
e
5
p y
g
0
a l
0
E
s a
y
s p
s p
d
e s
g
SFE
e
d
R
e
2
2
s
5 .
5 .
l o
N
A /
t u
s p
s p
o i
n
6
There is a limitation on FEA range vs. pulse width.
Falling Edge Adjust DAC Outputs
DAC_FALL_(0–3) are analog voltage outputs from the on-
board DACs which program the falling edge delay elements
of each channel.
DAC_FALL_(0-3) pins are for test purposes only. Nothing
should be connected to these pins.
Thermal Monitor
The Edge629 features a thermal diode string consisting
of 5 diodes as shown in Figure 4 below. This string allows
accurate die temperature measurements.
When an external bias current of up to 100 A is injected
through the string, the voltage measured across the AN-
ODE and CATHODE pins maps directly to the Edge629
junction temperature (see Figure 5).
I
p n
t u
Figure 4. Thermal Diode String
9
8
7
6
5
P
1
0
0
0
0
0
l u
0 .
0
0
0
0
0
e s
s n
s p
s p
s p
s p
s p
W
d i
CATHODE
h t
ANODE
Temperature Coefficient = –7.8 mV/˚C
Bias Current
E F
±
±
±
±
±
±
A
2
2
2
2
2
1
5
5
5
5
0
0
R
Edge629
0
0
0
0
0
0
n a
s p
s p
s p
s p
s p
s p
e g
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