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DS90LV027A
SNLS026D – MARCH 2000 – REVISED JUNE 2016
DS90LV027A LVDS Dual High Speed Differential Driver
1 Features
3 Description
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The DS90LV027A is a dual LVDS driver device
optimized for high data rate and low-power
applications. The device is designed to support data
rates in excess of 600 Mbps (300 MHz) using Low
Voltage Differential Signaling (LVDS) technology. The
DS90LV027A is a current mode driver allowing power
dissipation to remain low even at high frequency. In
addition, the short circuit fault current is also
minimized.
1
>600-Mbps (300 MHz) Switching Rates
0.3-ns Typical Differential Skew
0.7-ns Maximum Differential Skew
1.5-ns Maximum Propagation Delay
3.3-V Power Supply Design
±360-mV Differential Signaling
Low Power Dissipation (46 mW at 3.3-V Static)
Flow-Through Design Simplifies PCB Layout
Interoperable With Existing 5-V LVDS Devices
Power-Off Protection (Outputs in High Impedance)
Conforms to TIA/EIA-644 Standard
8-Pin SOIC Package Saves Space
Industrial Temperature Operating Range: −40°C
to 85°C
The device is in a 8-pin SOIC package. The
DS90LV027A has a flow-through design for easy
printed-circuit board (PCB) layout. The differential
driver outputs provides low EMI with its typical low
output swing of 360 mV. It is perfect for high-speed
transfer of clock and data. The DS90LV027A can be
paired with its companion dual line receiver, the
DS90LV028A, or with any of TI's LVDS receivers, to
provide a high-speed point-to-point LVDS interface.
2 Applications
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Device Information(1)
Multi-Function Printers
LVCMOS-to-LVDS Translation
Building and Factory Automation
Grid Infrastructure
PART NUMBER
DS90LV027A
PACKAGE
SOIC (8)
BODY SIZE (NOM)
4.90 mm × 3.91 mm
(1) For all available packages, see the orderable addendum at
the end of the data sheet.
space
Functional Diagrams
DO+ 1
DI 1
D
DO- 1
Copyright © 2016, Texas Instruments Incorporated
DO+ 2
DI 2
D
DO- 2
Copyright © 2016, Texas Instruments Incorporated
1
An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications,
intellectual property matters and other important disclaimers. PRODUCTION DATA.
DS90LV027A
SNLS026D – MARCH 2000 – REVISED JUNE 2016
www.ti.com
Table of Contents
1
2
3
4
5
6
7
8
Features ..................................................................
Applications ...........................................................
Description .............................................................
Revision History.....................................................
Pin Configuration and Functions .........................
Specifications.........................................................
1
1
1
2
3
4
6.1
6.2
6.3
6.4
6.5
6.6
6.7
4
4
4
4
5
5
6
Absolute Maximum Ratings ......................................
ESD Ratings..............................................................
Recommended Operating Conditions ......................
Thermal Information ..................................................
Electrical Characteristics ..........................................
Switching Characteristics ..........................................
Typical Characteristics ..............................................
Parameter Measurement Information .................. 9
Detailed Description ............................................ 10
8.1 Overview ................................................................. 10
8.2 Functional Block Diagrams ..................................... 10
8.3 Feature Description................................................. 11
8.4 Device Functional Modes........................................ 11
9
Application and Implementation ........................ 12
9.1 Application Information............................................ 12
9.2 Typical Application .................................................. 12
10 Power Supply Recommendations ..................... 13
11 Layout................................................................... 14
11.1 Layout Guidelines ................................................. 14
11.2 Layout Example .................................................... 14
12 Device and Documentation Support ................. 15
12.1
12.2
12.3
12.4
12.5
12.6
Documentation Support ........................................
Receiving Notification of Documentation Updates
Community Resources..........................................
Trademarks ...........................................................
Electrostatic Discharge Caution ............................
Glossary ................................................................
15
15
15
15
15
15
13 Mechanical, Packaging, and Orderable
Information ........................................................... 15
4 Revision History
NOTE: Page numbers for previous revisions may differ from page numbers in the current version.
Changes from Revision C (April 2013) to Revision D
•
Added ESD Ratings table, Feature Description section, Device Functional Modes, Application and Implementation
section, Power Supply Recommendations section, Layout section, Device and Documentation Support section, and
Mechanical, Packaging, and Orderable Information section .................................................................................................. 1
Changes from Revision B (April 2013) to Revision C
•
2
Page
Page
Changed layout of National Data Sheet to TI format ............................................................................................................. 1
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5 Pin Configuration and Functions
D Package
8-Pin SOIC
Top View
VCC
1
8
D0- 1
DI 1
2
7
D0+ 1
DI 2
3
6
D0+ 2
GND
4
5
D0- 2
Pin Functions
PIN
I/O
DESCRIPTION
NAME
NO.
DI
2, 3
I
TTL/CMOS driver input pins
DO+
6, 7
O
Noninverting LVDS driver output pin
DO–
5, 8
O
Inverting LVDS driver output pin
GND
4
—
Ground pin
VCC
1
—
Positive power supply pin, 3.3 V ± 0.3 V
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6 Specifications
6.1 Absolute Maximum Ratings
over operating free-air temperature range (unless otherwise noted) (1)
MIN
MAX
UNIT
Supply voltage, VCC
–0.3
4
V
Input voltage, DI
–0.3
3.6
V
Output voltage, DO±
–0.3
3.9
V
1190
mW
9.5 mW/°C
above 25°C
°C
260
°C
150
°C
D package
Maximum package power dissipation at 25°C
Derate D package
Lead temperature range, soldering (4 s)
Storage temperature, Tstg
(1)
–65
Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings
only, which do not imply functional operation of the device at these or any other conditions beyond those indicated under Recommended
Operating Conditions. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.
6.2 ESD Ratings
VALUE
Human-body model (HBM), per ANSI/ESDA/JEDEC JS-001
V(ESD)
(1)
(2)
Electrostatic discharge
(1)
UNIT
±8000
Charged-device model (CDM), per JEDEC specification JESD22-C101 (2)
±1000
EIAJ, 0 Ω, 200 pF
±1000
IEC direct, 330 Ω, 150 pF
±4000
V
JEDEC document JEP155 states that 500-V HBM allows safe manufacturing with a standard ESD control process.
JEDEC document JEP157 states that 250-V CDM allows safe manufacturing with a standard ESD control process.
6.3 Recommended Operating Conditions
over operating free-air temperature range (unless otherwise noted)
VCC
Supply voltage
TA
Operating free-air temperature
MIN
NOM
MAX
UNIT
3
3.3
3.6
V
–40
25
85
°C
6.4 Thermal Information
DS90LV027A
THERMAL METRIC (1)
D (SOIC)
UNIT
8 PINS
Low-K thermal resistance (2)
212
High-K thermal resistance (2)
112
RθJA
Junction-to-ambient thermal resistance
RθJC(top)
Junction-to-case (top) thermal resistance
69.1
°C/W
RθJB
Junction-to-board thermal resistance
47.7
°C/W
ψJT
Junction-to-top characterization parameter
15.2
°C/W
ψJB
Junction-to-board characterization parameter
47.2
°C/W
RθJC(bot)
Junction-to-case (bottom) thermal resistance
—
°C/W
(1)
(2)
4
°C/W
For more information about traditional and new thermal metrics, see the Semiconductor and IC Package Thermal Metrics application
report.
Tested in accordance with the Low-K or High-K thermal metric definitions of EIA/JESD51-3 for leaded surface-mount packages.
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6.5 Electrical Characteristics
over operating free-air temperature range (unless otherwise noted) (1) (2)
PARAMETER
TEST CONDITIONS
MIN
TYP (3)
MAX
UNIT
250
VOD
Output differential voltage
RL = 100 Ω (see Figure 15), DO+, DO− pins
360
450
mV
ΔVOD
VOD magnitude change
RL = 100 Ω (see Figure 15), DO+, DO− pins
1
35
mV
VOH
Output high voltage
RL = 100 Ω (see Figure 15), DO+, DO− pins
1.4
1.6
V
VOL
Output low voltage
RL = 100 Ω (see Figure 15), DO+, DO− pins
0.9
1.1
VOS
Offset voltage
RL = 100 Ω (see Figure 15), DO+, DO− pins
1.125
1.2
1.375
ΔVOS
Offset magnitude change
RL = 100 Ω (see Figure 15), DO+, DO− pins
0
3
25
mV
IOXD
Power-off leakage
VOUT = VCC or GND, VCC = 0 V, DO+, DO− pins
±1
±10
μA
IOSD
Output short-circuit current
DO+, DO− pins
–8
mA
VIH
Input high voltage
DI pin
2
VCC
V
VIL
Input low voltage
DI pin
GND
0.8
V
IIH
Input high current
VIN = 3.3 V or 2.4 V, DI pin
±2
±10
μA
IIL
Input low current
VIN = GND or 0.5 V, DI pin
±1
±10
μA
VCL
Input clamp voltage
ICL = −18 mA, DI pin
ICC
(1)
(2)
(3)
Power supply current
–5.7
–1.5
VIN = VCC or GND, VCC pin
–0.6
No load
RL = 100 Ω
V
V
V
8
14
14
20
mA
Current into device pins is defined as positive. Current out of device pins is defined as negative. All voltages are referenced to ground
except VOD.
The DS90LV027A is a current mode device and only function with datasheet specification when a resistive load is applied to the drivers
outputs.
All typicals are given for: VCC = 3.3 V and TA = 25°C.
6.6 Switching Characteristics
RL = 100 Ω and CL = 15 pF, see Figure 16 and Figure 17 (unless otherwise noted) (1) (2) (3)
PARAMETER
TEST CONDITIONS
MIN
TYP (4)
MAX
UNIT
tPHLD
Differential propagation delay high to low
0.3
0.8
1.5
ns
tPLHD
Differential propagation delay low to high
0.3
1.1
1.5
ns
tSKD1
Differential pulse skew |tPHLD − tPLHD| (5)
0
0.3
0.7
ns
0
0.4
(6)
tSKD2
Channel to channel skew
0.8
ns
tSKD3
Differential part to part skew (7)
0
1
ns
tSKD4
Differential part to part skew (8)
0
1.2
ns
tTLH
Transition low to high time
0.2
0.5
1
ns
tTHL
Transition high to low time
0.2
0.5
1
fMAX
Maximum operating frequency (9)
(1)
(2)
(3)
(4)
(5)
(6)
(7)
(8)
(9)
350
ns
MHz
These parameters are ensured by design. The limits are based on statistical analysis of the device over PVT (process, voltage,
temperature) ranges.
CL includes probe and fixture capacitance.
Generator waveform for all tests unless otherwise specified: f = 1 MHz, ZO = 50 Ω, tr ≤ 1 ns, tf ≤ 1 ns (10%-90%).
All typicals are given for: VCC = 3.3 V and TA = 25°C.
tSKD1, |tPHLD − tPLHD|, is the magnitude difference in differential propagation delay time between the positive going edge and the negative
going edge of the same channel.
tSKD2 is the Differential Channel to Channel Skew of any event on the same device.
tSKD3, Differential Part to Part Skew, is defined as the difference between the minimum and maximum specified differential propagation
delays. This specification applies to devices at the same VCC and within 5°C of each other within the operating temperature range.
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.
fMAX generator input conditions: tr = tf < 1 ns (0% to 100%), 50% duty cycle, 0 V to 3 V. Output criteria: duty cycle = 45% / 55%,
VOD > 250 mV, all channels switching.
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6.7 Typical Characteristics
6
Figure 1. Output High Voltage
vs Power Supply Voltage
Figure 2. Output Low Voltage
vs Power Supply Voltage
Figure 3. Output Short-Circuit Current
vs Power Supply Voltage
Figure 4. Differential Output Voltage
vs Power Supply Voltage
Figure 5. Differential Output Voltage
vs Load Resistor
Figure 6. Offset Voltage
vs Power Supply Voltage
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Typical Characteristics (continued)
Figure 7. Power Supply Current
vs Power Supply Voltage
Figure 8. Power Supply Current
vs Ambient Temperature
Figure 9. Differential Propagation Delay
vs Power Supply Voltage
Figure 10. Differential Propagation Delay
vs Ambient Temperature
Figure 11. Differential Skew
vs Power Supply Voltage
Figure 12. Differential Skew
vs Ambient Temperature
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Typical Characteristics (continued)
Figure 13. Transition Time
vs Power Supply Voltage
8
Figure 14. Transition Time
vs Ambient Temperature
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7 Parameter Measurement Information
DO+
RL / 2
2V
DI
VOS
D
VOD
0.8 V
SI
RL / 2
DOCopyright © 2016, Texas Instruments Incorporated
Figure 15. Differential Driver DC Test Circuit
DI
Generator
D
DO+
CL
RL
50 Ÿ
DO-
Copyright © 2016, Texas Instruments Incorporated
Figure 16. Differential Driver Propagation Delay and Transition Time Test Circuit
3V
DI
1.5 V
1.5 V
tPHLD
tPLH
DO-
0V
0 V (Differential)
DO+
0V
VOH
VOL
80 %
VDIFF
80 %
0V
20 %
0V
VDIFF = (DO+) ± (DO-)
tTHL
20 %
tTHL
Figure 17. Differential Driver Propagation Delay and Transition Time Waveforms
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8 Detailed Description
8.1 Overview
LVDS drivers and receivers are intended to be primarily used in an uncomplicated point-to-point configuration as
is shown in Figure 19. 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 differential impedance of the media
is in the range of 100 Ω. A termination resistor of 100 Ω (selected to match the media), and is placed as close to
the receiver input pins as possible. The termination resistor converts the driver output current (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 considered. The DS90LV027A
differential line driver is a balanced current source design. A current mode driver, generally speaking has a high
output impedance and supplies a constant current for a range of loads (a voltage mode driver on the other hand
supplies a constant voltage for a range of loads). Current is switched through the load in one direction to produce
a logic state and in the other direction to produce the other logic state. The output current is typically 3.1 mA, a
minimum of 2.5 mA, and a maximum of 4.5 mA. The current mode driver requires (as discussed above) that a
resistive termination be employed to terminate the signal and to complete the loop as shown in Figure 19. AC or
unterminated configurations are not allowed. The 3.1-mA loop current develops a differential voltage of 310 mV
across the 100-Ω termination resistor which the receiver detects with a 250-mV minimum differential noise
margin, (driven signal minus receiver threshold (250 mV – 100 mV = 150 mV). The signal is centered around 1.2
V (Driver Offset, VOS) with respect to ground as shown in Figure 18.
NOTE
The steady-state voltage (VSS) peak-to-peak swing is twice the differential voltage (VOD)
and is typically 620 mV.
The current mode driver provides substantial benefits over voltage mode drivers, such as an RS-422 driver. Its
quiescent current remains relatively flat versus switching frequency. Whereas the RS-422 voltage mode driver
increases exponentially in most case from 20 MHz to 50 MHz. This is due to the overlap current that flows
between the rails of the device when the internal gates switch. Whereas the current mode driver switches a fixed
current between its output without any substantial overlap current. This is similar to some ECL and PECL
devices, but without the heavy static ICC requirements of the ECL/PECL designs. LVDS requires >80% less
current than similar PECL devices. AC specifications for the driver are a tenfold improvement over other existing
RS-422 drivers.
8.2 Functional Block Diagrams
DO+ 1
DI 1
D
DO- 1
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DO+ 2
DI 2
D
DO- 2
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10
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8.3 Feature Description
8.3.1 LVDS Fail-Safe
This section addresses the common concerns of fail-safe biasing of LVDS interconnects, specifically looking at
the DS90LV027A driver outputs and the DS90LV028A receiver inputs.
The LVDS receiver is a high-gain, high-speed device that amplifies a small differential signal (20 mV) to CMOS
logic levels. Due to the high gain and tight threshold of the receiver, take care to prevent noise from appearing as
a valid signal.
The internal fail-safe circuitry of the receiver is designed to source or 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 DS90LV028A is a dual receiver device, and if an application requires only 1 receiver,
the unused channel inputs must be left OPEN. Do not tie unused receiver inputs to ground or any other
voltages. The input is biased by internal high value pullup and pulldown resistors to set the output to a HIGH
state. This internal circuitry ensures a HIGH, stable output state for open inputs.
2. Terminated Input: If the DS90LV027A driver is disconnected (cable unplugged), or if the DS90LV027A driver
is in a TRI-STATE or power-off condition, the receiver output is in a HIGH state again, even with the end of
cable 100-Ω 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 10 mV 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 must be used. Twisted pair cable offers better balance than flat ribbon cable.
3. Shorted Inputs: If a fault condition occurs that shorts the receiver inputs together, thus resulting in a 0-V
differential input voltage, the receiver output remains in a HIGH state. Shorted input fail-safe is not supported
across the common-mode range of the device (GND to 2.4 V). It is only supported with inputs shorted and no
external common-mode voltage applied.
External lower value pullup and pulldown resistors (for a stronger bias) may be used to boost fail-safe in the
presence of higher noise levels. The pullup and pulldown resistors must be in the 5-kΩ to 15-kΩ range to
minimize loading and waveform distortion to the driver. The common-mode bias point must be set to
approximately 1.2 V (less than 1.75 V) to be compatible with the internal circuitry.
3V
DIN
0V
V0H
DOUT-
V0S (1.2V typical)
V0D
SINGLE-ENDED
DOUT+
V0L
+V0D
DOUT+ ± DOUT-
VSS
0V
0V (DIFF.)
DIFFERENTIAL OUTPUT
-V0D
Figure 18. Driver Output Levels
8.4 Device Functional Modes
Table 1 lists the functional modes of the DS90LV027A.
Table 1. Truth Table
INPUT
OUTPUTS
DI
DO+
DO–
L
L
H
H
H
L
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9 Application and Implementation
NOTE
Information in the following applications sections is not part of the TI component
specification, and TI does not warrant its accuracy or completeness. TI’s customers are
responsible for determining suitability of components for their purposes. Customers should
validate and test their design implementation to confirm system functionality.
9.1 Application Information
The DS90LV027A 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.
General application guidelines and hints for LVDS drivers and receivers may be found in the following application
notes:
• LVDS Owner's Manual
• AN-808 Long Transmission Lines and Data Signal Quality
• AN-977 LVDS Signal Quality: Jitter Measurements Using Eye Patterns Test Report
• AN-971 An Overview of LVDS Technology
• AN-916 A Practical Guide To Cable Selection
• AN-805 Calculating Power Dissipation for Differential Line Drivers
• AN-903 A Comparison of Differential Termination Techniques
9.2 Typical Application
Any LVDS
Receiver
DATA
INPUT
RT
100:
+
-
DATA
OUTPUT
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Figure 19. LVDS Application Schematic
9.2.1 Design Requirements
When using LVDS devices, it is important to remember to specify controlled impedance PCB traces, cable
assemblies, and connectors. All components of the transmission media must have a matched differential
impedance of about 100 Ω. They must not introduce major impedance discontinuities. Balanced cables (for
example, twisted pair) are usually better than unbalanced cables (ribbon cable) 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 as common-mode (not differential mode) noise which is rejected by the LVDS receiver.
For cable distances < 0.5 M, most cables can be made to work effectively. For distances 0.5 M ≤ d ≤ 10 M,
CAT5 (Category 5) twisted pair cable works well, is readily available, and relatively inexpensive.
12
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Typical Application (continued)
9.2.2 Detailed Design Procedure
9.2.2.1 Probing LVDS Transmission Lines
Always use high impedance (>100 kΩ), low capacitance (