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零件编号 | E142AHF | ||
描述 | Per Pin timing Deskew w 4x2 Cross Point Switch | ||
制造商 | Semtech Corporation | ||
LOGO | |||
1 Page
EDGE HIGH-PERFORMANCE PRODUCTS
Description
Edge142
Per Pin timing Deskew w 4x2
Cross Point Switch
Features
The Edge142 is a 4 X 2 cross point switch with output
edge deskew capability. Manufactured in a high
performance bipolar process, it is designed primarily for
channel deskew applications in VLSI and Mixed-Signal
test equipment.
Any of the four input signals may be selected as the
source for either output. The 142 performs test head
multiplexing, adjacent channel multiplexing, and signal
buffering for both the drive and receive signals, in addition
to timing deskew.
• Very Narrow (<1 ns) Pulse Width Capability
• Fmax > 850 MHz
• Independent Delay Adjustments for Positive and
Negative Transitions
• Delay Range of 1.5 ns
• Trailing Edge Adjust Range of 300 ps
• Small Footprint: 52-pin MQFP Package
(10 X 10 mm) with Internal Heat Spreader or
Die Form
The delay value (and resolution) is controlled via an
external voltage DAC. The delay element is designed
specifically to be monotonic and very stable while
delaying a very narrow pulse over a limited delay range.
Applications
The part offers separate delays for rising vs. falling edges.
The rising edge delay range is 1.5 ns and the falling
edge adjustment range is 300 ps.
The Edge142 is also well suited for 1:2 or 1:4 signal
fanout applications that require:
- multiple signal sources
- output enable / disable
- timing deskew on the output
signals.
• Automatic Test Equipment
– Per pin deskew in VLSI, Mixed-Signal, and Memory
Testers
– Clock Distribution with timing adjustment
Functional Block Diagram
VDELAY 0
VFALL 0
IN0 / 0*
IN1 / 1*
IN2 / 2*
IN3 / 3*
4X2
∆T
∆T
OUT0 / 0*
MUX OUT0 / 0*
MUX OUT1 / 1*
OUT1 / 1*
Revision 1, February 14, 2000
VFALL 1
VDELAY 1
1
www.semtech.com
Edge142
EDGE HIGH-PERFORMANCE PRODUCTS
Circuit Description (continued)
Analog Delay Inputs
Compensation Pins
VDELAY, VFALL, and VMID are analog voltage inputs which
control the delay of the rising and falling edge. All three
inputs may vary from +0.1V (minimum delay) to -1.3V
(maximum delay).
COMP1 and COMP2 are Op Amp compensation pins.
For proper Edge142 functionality, these pins require a
.1 µF capacitor to ground.
VMID should be permanently set to the middle of the
overall voltage range spanned by VFALL (~ -0.6V). A
fixed resistor to ground will usually suffice. The exact
setting of VFALL will vary depending on the required delay
range of the falling edge.
These inputs are designed to sink a constant input
current, typically 1.0 mA (with REXT1 = 2.94 KΩ), over
their operating range from +0.1V to -1.3V. Any voltage
DAC used to drive these inputs directly needs to source
at least 1.0 mA. Any current DAC used needs to factor
in the constant 1.0 mA input current.
Thermal Monitor
The Edge142 includes an on-chip thermal monitor
accessible through the pins TDP and TDN. These nodes
connect to five diodes in series (see Figure 6) and may
be used to accurately measure the junction temperature
at any time.
TDP
Bias Current
The equation used to establish the VDELAY, VMID, and
VFALL input currents is:
I (VFALL, VDELAY, VMID) = 3.0V / REXT1.
The fact that the VDELAY, VFALL, and VMID inputs have
internal current sources allows a voltage DAC capable
of generating only positive voltages and an external
resistor network to be pulled down to the Edge142's
negative input voltage compliance. These current
sources are designed to be constant over temperature,
so changes in system temperature will not translate into
a delay voltage shift.
˚Temperature coefficient = –10 mV/ C
TDN
Figure 6. Thermal Diode String
Using a different REXT1 will program a different input
current. However, the value of this current does not
affect deskew range or performance. The ability to vary
this current allows a more flexible interface to a variety
of DAC programming techniques.
An external bias current of 100 µA is injected through
the string, and the measured voltage corresponds to a
specific junction temperature with the following equation:
TJ(˚C) = {(V(TDP) – V(TDN)) / 5 – .7} / (-.00208).
VDELAY, VFALL, and VMID all require current flow. Do
NOT leave any of these input pins floating. If an
application does not require any falling edge delay,
connect all VDELAY and VMID pins to ground.
2000 Semtech Corp.
8
www.semtech.com
EDGE HIGH-PERFORMANCE PRODUCTS
Recommended Operating Conditions
Edge142
Parameter
Device Ground
Negative Power Supply
Ambient Operating Temperature
Symbol
GND
VEE
TA
Min
Typ
Max
Units
000V
-4.2 -5.2 -5.5
0 +70
V
oC
Absolute Maximum Ratings
Parameter
VEE (relative to GND)
Voltage on any Digital Pin
Output Current
Ambient Operating Temperature
Storage Temperature
Junction Temperature
Soldering Temperature
(5 seconds, 1/4" from pin)
Symbol
TA
TS
TJ
TSOL
Min
Typ
Max
Units
-7.0 0 V
VEE
GND
V
-50 mA
-55
+70
oC
-65
+150
oC
+150
oC
260
oC
2000 Semtech Corp.
16
www.semtech.com
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页数 | 19 页 | ||
下载 | [ E142AHF.PDF 数据手册 ] |
零件编号 | 描述 | 制造商 |
E142AHF | Per Pin timing Deskew w 4x2 Cross Point Switch | Semtech Corporation |
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