NSC DS90LV048ATMTC

DS90LV048A
3V LVDS Quad CMOS Differential Line Receiver
General Description
Features
The DS90LV048A is a quad CMOS flow-through differential
line receiver designed for applications requiring ultra low
power dissipation and high data rates. The device is designed to support data rates in excess of 400 Mbps (200
MHz) utilizing Low Voltage Differential Signaling (LVDS)
technology.
The DS90LV048A accepts low voltage (350 mV typical) differential input signals and translates them to 3V CMOS output levels. The receiver supports a TRI-STATE ® function that
may be used to multiplex outputs. The receiver also supports
open, shorted and terminated (100Ω) input fail-safe. The receiver output will be HIGH for all fail-safe conditions. The
DS90LV048A has a flow-through pinout for easy PCB layout.
The EN and EN* inputs are ANDed together and control the
TRI-STATE outputs. The enables are common to all four receivers. The DS90LV048A and companion LVDS line driver
(eg. DS90LV047A) provide a new alternative to high power
PECL/ECL devices for high speed point-to-point interface
applications.
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Connection Diagram
Functional Diagram
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> 400 Mbps (200 MHz) switching rates
Flow-through pinout simplifies PCB layout
150 ps channel-to-channel skew (typical)
100 ps differential skew (typical)
2.7 ns maximum propagation delay
3.3V power supply design
High impedance LVDS inputs on power down
Low Power design (40mW 3.3V static)
Interoperable with existing 5V LVDS drivers
Accepts small swing (350 mV typical) differential signal
levels
Supports open, short and terminated input fail-safe
Conforms to ANSI/TIA/EIA-644 Standard
Industrial temperature operating range (-40˚C to +85˚C)
Available in SOIC and TSSOP package
Dual-in-Line
DS100888-1
Order Number DS90LV048ATM, DS90LV048ATMTC
See NS Package Number M16A, MTC16
DS100888-2
INPUTS
OUTPUT
EN
ENABLES
EN*
RIN+ − RIN−
ROUT
H
L or Open
VID ≥ 0.1V
H
All other combinations of ENABLE inputs
VID ≤ −0.1V
L
Full Fail-safe
OPEN/SHORT
or Terminated
H
X
Z
TRI-STATE ® is a registered trademark of National Semiconductor Corporation.
© 1999 National Semiconductor Corporation
DS100888
www.national.com
DS90LV048A 3V LVDS Quad CMOS Differential Line Receiver
July 1999
Absolute Maximum Ratings (Note 1)
(4 sec.)
Maximum Junction Temperature
ESD Rating (Note 10)
(HBM, 1.5 kΩ, 100 pF)
(EIAJ, 0 Ω, 200 pF)
If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales Office/
Distributors for availability and specifications.
Supply Voltage (VCC)
−0.3V to +4V
−0.3V to 3.9V
Input Voltage (RIN+, RIN−)
Enable Input Voltage (EN, EN*)
−0.3V to (VCC + 0.3V)
−0.3V to (VCC + 0.3V)
Output Voltage (ROUT)
Maximum Package Power Dissipation +25˚C
M Package
1025 mW
MTC Package
866 mW
Derate M Package
8.2 mW/˚C above +25˚C
Derate MTC Package
6.9 mW/˚C above +25˚C
Storage Temperature Range
−65˚C to +150˚C
Lead Temperature Range Soldering
+260˚C
+150˚C
≥ 10 kV
≥ 1200 V
Recommended Operating
Conditions
Supply Voltage (VCC)
Receiver Input Voltage
Operating Free Air
Temperature (TA)
Min
+3.0
GND
Typ
+3.3
Max
+3.6
+3.0
Units
V
V
−40
25
+85
˚C
Min
Typ
Max
Units
Electrical Characteristics
Over Supply Voltage and Operating Temperature ranges, unless otherwise specified. (Notes 2, 3)
Symbol
Parameter
Conditions
Pin
VTH
Differential Input High Threshold
VCM = +1.2V, 0.05V, 2.95V (Note 13)
RIN+,
VTL
Differential Input Low Threshold
VCMR
Common-Mode Voltage Range
VID = 200mV pk to pk (Note 5)
0.1
IIN
Input Current
VIN = +2.8V
−10
RIN−
mV
mV
2.3
V
+10
µA
+10
µA
+20
µA
-20
2.7
3.3
V
IOH = −0.4 mA, Input terminated
2.7
3.3
V
IOH = −0.4 mA, Input shorted
2.7
3.3
VIN = +3.6V
Output High Voltage
−100
±5
±1
±1
VCC = 3.6V or 0V
VIN = 0V
VOH
+100
−10
VCC = 0V
IOH = −0.4 mA, VID = +200 mV
VOL
Output Low Voltage
IOL = 2 mA, VID = −200 mV
IOS
Output Short Circuit Current
Enabled, VOUT = 0V (Note 11)
Disabled, VOUT = 0V or VCC
ROUT
IOZ
Output TRI-STATE Current
VIH
Input High Voltage
VIL
Input Low Voltage
II
Input Current
VIN = 0V or VCC, Other Input = VCC or
GND
VCL
Input Clamp Voltage
ICC
No Load Supply Current
Receivers Enabled
ICL = −18 mA
EN = VCC, Inputs Open
ICCZ
No Load Supply Current
EN,
EN*
V
0.05
0.25
V
−15
−47
−100
mA
−10
±1
+10
µA
2.0
VCC
V
GND
0.8
V
+10
µA
9
15
mA
1
5
mA
Units
−10
±5
−1.5
−0.8
VCC
EN = GND, Inputs Open
V
Receivers Disabled
Switching Characteristics
Over Supply Voltage and Operating Temperature ranges, unless otherwise specified. (Notes 3, 4, 7, 8)
Symbol
Min
Typ
Max
tPHLD
Differential Propagation Delay High to Low
Parameter
CL = 15 pF
1.2
2.0
2.7
ns
tPLHD
Differential Propagation Delay Low to High
VID = 200 mV
1.2
1.9
2.7
ns
(Figure 1 and Figure 2)
0
0.1
0.4
ns
0
0.15
0.5
ns
ns
tSKD1
Differential Pulse Skew |tPHLD − tPLHD| (Note 6)
tSKD2
Differential Channel-to-Channel Skew; same device
(Note 7)
Conditions
tSKD3
Differential Part to Part Skew (Note 8)
1.0
tSKD4
Differential Part to Part Skew (Note 9)
1.5
ns
tTLH
Rise Time
0.5
1.0
ns
tTHL
Fall Time
0.35
1.0
ns
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Switching Characteristics
(Continued)
Over Supply Voltage and Operating Temperature ranges, unless otherwise specified. (Notes 3, 4, 7, 8)
Symbol
Typ
Max
tPHZ
Disable Time High to Z
Parameter
RL = 2 kΩ
8
14
ns
tPLZ
Disable Time Low to Z
CL = 15 pF
8
14
ns
(Figure 3 and Figure 4)
9
14
ns
9
14
tPZH
Enable Time Z to High
tPZL
Enable Time Z to Low
fMAX
Maximum Operating Frequency (Note 14)
Conditions
All Channels Switching
Min
200
250
Units
ns
MHz
Note 1: “Absolute Maximum Ratings” are those values beyond which the safety of the device cannot be guaranteed. They are not meant to imply that the devices
should be operated at these limits. The table of “Electrical Characteristics” specifies conditions of device operation.
Note 2: Current into device pins is defined as positive. Current out of device pins is defined as negative. All voltages are referenced to ground unless otherwise specified.
Note 3: All typicals are given for: VCC = +3.3V, TA = +25˚C.
Note 4: Generator waveform for all tests unless otherwise specified: f = 1 MHz, ZO = 50Ω, tr and tf (0% to 100%) ≤ 3 ns for RIN.
Note 5: The VCMR range is reduced for larger VID. Example: if VID = 400mV, the VCMR is 0.2V to 2.2V. The fail-safe condition with inputs shorted is not supported
over the common-mode range of 0V to 2.4V, but is supported only with inputs shorted and no external common-mode voltage applied. A VID up to VCC− 0V may be
applied to the RIN+/ RIN− inputs with the Common-Mode voltage set to VCC/2. Propagation delay and Differential Pulse skew decrease when VID is increased from
200mV to 400mV. Skew specifications apply for 200mV ≤ VID ≤ 800mV over the common-mode range .
Note 6: tSKD1 is the magnitude difference in differential propagation delay time between the positive going edge and the negative going edge of the same channel
Note 7: tSKD2, Channel-to-Channel Skew is defined as the difference between the propagation delay of one channel and that of the others on the same chip with
any event on the inputs.
Note 8: tSKD3, part to part skew, is the differential channel-to-channel skew of any event between devices. This specification applies to devices at the same VCC,
and within 5˚C of each other within the operating temperature range.
Note 9: tSKD4, part to part skew, is the differential channel-to-channel skew of any event between devices. This specification applies to devices over recommended
operating temperature and voltage ranges, and across process distribution. tSKD4 is defined as |Max−Min| differential propagation delay.
Note 10: ESD Rating:HBM (1.5 kΩ, 100 pF) ≥ 10kV
EIAJ (0Ω, 200 pF) ≥ 1200V
Note 11: Output short circuit current (IOS) is specified as magnitude only, minus sign indicates direction only. Only one output should be shorted at a time, do not
exceed maximum junction temperature specification.
Note 12: CL includes probe and jig capacitance.
Note 13: VCC is always higher than RIN+ and RIN− voltage. RIN− and RIN+ are allowed to have a voltage range −0.2V to VCC− VID/2. However, to be compliant with
AC specifications, the common voltage range is 0.1V to 2.3V
Note 14: fMAX generator input conditions: tr = tf < 1 ns (0% to 100%), 50% duty cycle, differential (1.05V to 1.35V peak to peak). Output criteria: 60/40% duty cycle,
VOL (max 0.4V), VOH (min 2.7V), Load = 15 pF (stray plus probes).
Parameter Measurement Information
DS100888-3
FIGURE 1. Receiver Propagation Delay and Transition Time Test Circuit
DS100888-4
FIGURE 2. Receiver Propagation Delay and Transition Time Waveforms
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Parameter Measurement Information
(Continued)
DS100888-5
CL includes load and test jig capacitance.
S1 = VCC for tPZL and tPLZ measurements.
S1 = GND for tPZH and tPHZ measurements.
FIGURE 3. Receiver TRI-STATE Delay Test Circuit
DS100888-6
FIGURE 4. Receiver TRI-STATE Delay Waveforms
Typical Application
Balanced System
DS100888-7
FIGURE 5. Point-to-Point Application
Applications Information
the media is in the range of 100Ω. A termination resistor of
100Ω (selected to match the media), and is located as close
to the receiver input pins as possible. The termination resistor converts the driver output (current mode) into a voltage
that is detected by the receiver. Other configurations are
possible such as a multi-receiver configuration, but the effects of a mid-stream connector(s), cable stub(s), and other
impedance discontinuities as well as ground shifting, noise
margin limits, and total termination loading must be taken
into account.
General application guidelines and hints for LVDS drivers
and receivers may be found in the following application
notes: LVDS Owner’s Manual (lit #550062-001), AN808,
AN977, AN971, AN916, AN805, AN903.
LVDS drivers and receivers are intended to be primarily used
in an uncomplicated point-to-point configuration as is shown
in Figure 5. This configuration provides a clean signaling environment for the fast edge rates of the drivers. The receiver
is connected to the driver through a balanced media which
may be a standard twisted pair cable, a parallel pair cable, or
simply PCB traces. Typically, the characteristic impedance of
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4
Applications Information
fully review dimensions to match differential impedance and
provide isolation for the differential lines. Minimize the number or vias and other discontinuities on the line.
(Continued)
The DS90LV048A differential line receiver is capable of detecting signals as low as 100mV, over a ± 1V common-mode
range centered around +1.2V. This is related to the driver offset voltage which is typically +1.2V. The driven signal is centered around this voltage and may shift ± 1V around this center point. The ± 1V shifting may be the result of a ground
potential difference between the driver’s ground reference
and the receiver’s ground reference, the common-mode effects of coupled noise, or a combination of the two. The AC
parameters of both receiver input pins are optimized for a
recommended operating input voltage range of 0V to +2.4V
(measured from each pin to ground). The device will operate
for receiver input voltages up to VCC, but exceeding VCC will
turn on the ESD protection circuitry which will clamp the bus
voltages.
Avoid 90˚ turns (these cause impedance discontinuities).
Use arcs or 45˚ bevels.
Within a pair of traces, the distance between the two traces
should be minimized to maintain common-mode rejection of
the receivers. On the printed circuit board, this distance
should remain constant to avoid discontinuities in differential
impedance. Minor violations at connection points are allowable.
Termination:
Use a termination resistor which best matches the differential impedance or your transmission line. The resistor should
be between 90Ω and 130Ω. Remember that the current
mode outputs need the termination resistor to generate the
differential voltage. LVDS will not work without resistor termination. Typically, connecting a single resistor across the pair
at the receiver end will suffice.
Surface mount 1% to 2% resistors are best. PCB stubs,
component lead, and the distance from the termination to the
receiver inputs should be minimized. The distance between
the termination resistor and the receiver should be < 10mm
(12mm MAX)
Probing LVDS Transmission Lines:
Always use high impedance ( >
100kΩ), low
capacitance ( < 2 pF) scope probes with a wide bandwidth (1
GHz) scope. Improper probing will give deceiving results.
Cables and Connectors, General Comments:
When choosing cable and connectors for LVDS it is important to remember:
Use controlled impedance media. The cables and connectors you use should have a matched differential impedance
of about 100Ω. They should not introduce major impedance
discontinuities.
Balanced cables (e.g. twisted pair) are usually better than
unbalanced cables (ribbon cable, simple coax.) for noise reduction and signal quality. Balanced cables tend to generate
less EMI due to field canceling effects and also tend to pick
up electromagnetic radiation a common-mode (not differential mode) noise which is rejected by the receiver.
For cable distances < 0.5M, most cables can be made to
work effectively. For distances 0.5M ≤ d ≤ 10M, CAT 3 (category 3) twisted pair cable works well, is readily available
and relatively inexpensive.
Fail-Safe Feature:
The LVDS receiver is a high gain, high speed device that
amplifies a small differential signal (20mV) to CMOS logic
levels. Due to the high gain and tight threshold of the receiver, care should be taken to prevent noise from appearing
as a valid signal.
The receiver’s internal fail-safe circuitry is designed to
source/sink a small amount of current, providing fail-safe
protection (a stable known state of HIGH output voltage) for
floating, terminated or shorted receiver inputs.
1. Open Input Pins. The DS90LV048A is a quad receiver
device, and if an application requires only 1, 2 or 3 receivers, the unused channel(s) inputs should be left
OPEN. Do not tie unused receiver inputs to ground or
any other voltages. The input is biased by internal high
value pull up and pull down resistors to set the output to
a HIGH state. This internal circuitry will guarantee a
HIGH, stable output state for open inputs.
The DS90LV048A has a flow-through pinout that allows for
easy PCB layout. The LVDS signals on one side of the device easily allows for matching electrical lengths of the differential pair trace lines between the driver and the receiver as
well as allowing the trace lines to be close together to couple
noise as common-mode. Noise isolation is achieved with the
LVDS signals on one side of the device and the TTL signals
on the other side.
Power Decoupling Recommendations:
Bypass capacitors must be used on power pins. Use high
frequency ceramic (surface mount is recommended) 0.1µF
and 0.001µF capacitors in parallel at the power supply pin
with the smallest value capacitor closest to the device supply
pin. Additional scattered capacitors over the printed circuit
board will improve decoupling. Multiple vias should be used
to connect the decoupling capacitors to the power planes. A
10µF (35V) or greater solid tantalum capacitor should be
connected at the power entry point on the printed circuit
board between the supply and ground.
PC Board considerations:
Use at least 4 PCB layers (top to bottom); LVDS signals,
ground, power, TTL signals.
Isolate TTL signals from LVDS signals, otherwise the TTL
may couple onto the LVDS lines. It is best to put TTL and
LVDS signals on different layers which are isolated by a
power/ground plane(s)
Keep drivers and receivers as close to the (LVDS port side)
connectors as possible.
Differential Traces:
Use controlled impedance traces which match the differential impedance of your transmission medium (ie. cable) and
termination resistor. Run the differential pair trace lines as
close together as possible as soon as they leave the IC
(stubs should be < 10mm long). This will help eliminate reflections and ensure noise is coupled as common-mode. In
fact, we have seen that differential signals which are 1mm
apart radiate far less noise than traces 3mm apart since
magnetic field cancellation is much better with the closer
traces. In addition, noise induced on the differential lines is
much more likely to appear as common-mode which is rejected by the receiver.
Match electrical lengths between traces to reduce skew.
Skew between the signals of a pair means a phase difference between signals which destroys the magnetic field cancellation benefits of differential signals and EMI will result.
(Note the velocity of propagation, v = c/Er where c (the
speed of light) = 0.2997mm/ps or 0.0118 in/ps). Do not rely
solely on the autoroute function for differential traces. Care5
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Applications Information
Pin Descriptions
(Continued)
2.
Terminated Input. If the driver is disconnected (cable
unplugged), or if the driver is in a TRI-STATE or poweroff condition, the receiver output will again be in a HIGH
state, even with the end of cable 100Ω termination resistor across the input pins. The unplugged cable can become a floating antenna which can pick up noise. If the
cable picks up more than 10mV of differential noise, the
receiver may see the noise as a valid signal and switch.
To insure that any noise is seen as common-mode and
not differential, a balanced interconnect should be used.
Twisted pair cable will offer better balance than flat ribbon cable.
3. Shorted Inputs. If a fault condition occurs that shorts
the receiver inputs together, thus resulting in a 0V differential input voltage, the receiver output will remain in a
HIGH state. Shorted input fail-safe is not supported
across the common-mode range of the device (GND to
2.4V). It is only supported with inputs shorted and no external common-mode voltage applied.
External lower value pull up and pull down resistors (for a
stronger bias) may be used to boost fail-safe in the presence
of higher noise levels. The pull up and pull down resistors
should be in the 5kΩ to 15kΩ range to minimize loading and
waveform distortion to the driver. The common-mode bias
point should be set to approximately 1.2V (less than 1.75V)
to be compatible with the internal circuitry.
Pin No.
Name
2, 3, 6, 7
RIN+
Non-inverting receiver input pin
Description
1, 4, 5, 8
RIN−
Inverting receiver input pin
10, 11, 14,
ROUT
Receiver output pin
15
16
EN
Receiver enable pin: When EN is
low, the receiver is disabled.
When EN is high and EN* is low
or open, the receiver is enabled.
If both EN and EN* are open
circuit, then the receiver is
disabled.
9
EN*
Receiver enable pin: When EN*
is high, the receiver is disabled.
When EN* is low or open and
EN is high, the receiver is
enabled. If both EN and EN* are
open circuit, then the receiver is
disabled.
13
VCC
Power supply pin, +3.3V ± 0.3V
12
GND
Ground pin
Ordering Information
Operating
Package Type/
Temperature
Number
Order Number
−40˚C to +85˚C
SOP/M16A
DS90LV048ATM
−40˚C to +85˚C
TSSOP/MTC16
DS90LV048ATMTC
Typical Performance Curves
Output High Voltage vs
Power Supply Voltage
Output Low Voltage vs
Power Supply Voltage
DS100888-13
DS100888-12
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Typical Performance Curves
(Continued)
Output TRI-STATE Current vs
Power Supply Voltage
Output Short Circuit Current vs
Power Supply Voltage
DS100888-15
DS100888-14
Differential Transition Voltage vs
Power Supply Voltage
Power Supply Current
vs Frequency
DS100888-16
Power Supply Current vs
Ambient Temperature
DS100888-17
Differential Propagation Delay vs
Power Supply Voltage
DS100888-18
DS100888-19
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Typical Performance Curves
(Continued)
Differential Propagation Delay vs
Differential Input Voltage
Differential Propagation Delay vs
Ambient Temperature
DS100888-20
Differential Propagation Delay vs
Common-Mode Voltage
DS100888-21
Differential Skew vs
Power Supply Voltage
DS100888-23
DS100888-22
Differential Skew vs
Ambient Temperature
Transition Time vs
Power Supply Voltage
DS100888-24
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DS100888-25
8
Typical Performance Curves
(Continued)
Transition Time vs
Ambient Temperature
DS100888-26
9
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Physical Dimensions
inches (millimeters) unless otherwise noted
16-Lead (0.150" Wide) Molded Small Outline Package, JEDEC
Order Number DS90LV048ATM
NS Package Number M16A
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DS90LV048A 3V LVDS Quad CMOS Differential Line Receiver
Physical Dimensions
inches (millimeters) unless otherwise noted (Continued)
16-Lead (0.100" Wide) Molded Thin Shrink Small Outline Package, JEDEC
Order Number DS90LV048ATMTC
NS Package Number MTC16
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