Standard Products
UT54LVDS032LV Low Voltage Quad Receiver
Data Sheet
May, 2003
FEATURES
q>400.0 Mbps (200 MHz) switching rates
q+340mV differential signaling
q3.3 V power supply
qTTL compatible outputs
qCold spare all pins
qUltra low power CMOS technology
q4.0ns maximum propagation delay
q0.35ns maximum differential skew
qRadiation-hardened design; total dose irradiation testing to MIL-STD-883 Method 1019
-Total-dose: 300 krad(Si) and 1Mrad(Si)
-Latchup immune (LET > 100 MeV-cm2 /mg)
qPackaging options:
-16-lead flatpack (dual in-line)
qStandard Microcircuit Drawing 5962-98652
-QML Q and V compliant part
INTRODUCTION
The UT54LVDS032LV Quad Receiver is a quad CMOS 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 400.0 Mbps (200 MHz) utilizing Low Voltage Differential Signaling (LVDS) technology.
The UT54LVDS032LV accepts low voltage (340mV) differential input signals and translates them to 3V CMOS output levels. The receiver supports a three-state function that may be used to multiplex outputs. The receiver also supports OPEN, shorted and terminated (100Ω) input fail-safe. Receiver output will be HIGH for all fail-safe conditions.
The UT54LVDS032LV and companion quad line driver UT54LVDS031LV provides new alternatives to high power pseudo-ECL devices for high speed point-to-point interface applications.
All pins have Cold Spare buffers. These buffers will be high impedance when V DD is tied to VSS.
RIN1+ |
+ |
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RIN1- |
- |
RIN2+ |
+ |
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RIN2- |
- |
RIN3+ |
+ |
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RIN3- |
- |
RIN4+ |
+ |
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RIN4- |
- |
EN |
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EN
R1 ROUT1
R2 ROUT2
R3 ROUT3
R4 ROUT4
Figure 1. UT54LVDS032LV Quad Receiver Block Diagram
1
RIN1- |
1 |
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16 |
VDD |
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RIN1+ |
2 |
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15 |
RIN4- |
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ROUT1 |
3 |
UT54LVDS032LV |
14 |
RIN4+ |
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EN |
4 |
13 |
ROUT4 |
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Receiver |
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ROUT2 |
5 |
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12 |
EN |
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RIN2+ |
6 |
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11 |
ROUT3 |
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RIN2- |
7 |
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10 |
RIN3+ |
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VSS |
8 |
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9 |
R I N 3 - |
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Figure 2. UT54LVDS032LV Pinout |
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TRUTH TABLE |
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Enables |
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Input |
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Output |
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EN |
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EN |
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RIN+ - RIN- |
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ROUT |
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L |
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H |
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X |
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Z |
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All other combinations |
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VID > 0.1V |
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H |
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of ENABLE inputs |
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VID < -0.1V |
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L |
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Full Fail-safe |
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H |
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OPEN/SHORT or |
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Terminated |
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PIN DESCRIPTION |
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Pin No. |
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Name |
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Description |
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2, 6, 10, 14 |
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RIN+ |
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Non-inverting receiver input pin |
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1, 7, 9, 15 |
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RIN- |
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Inverting receiver input pin |
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3, 5, 11, 13 |
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ROUT |
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Receiver output pin |
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4 |
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EN |
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Active high enable pin, OR-ed |
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with EN |
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12 |
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EN |
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Active low enable pin, OR-ed |
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with EN |
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16 |
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VDD |
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Power supply pin, +3.3 + 0.3V |
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8 |
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VSS |
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Ground pin |
APPLICATIONS INFORMATION
The UT54LVDS032LV receiver’s intended use is primarily in an uncomplicated point-to-point configuration as is shown in Figure 3. This configuration provides a clean signaling environment for quick 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 the media is in the range of 100Ω. A termination resistor of 100Ω should be selected to match the media and is located as close to the receiver input pins as possible. The termination resistor converts the current sourced by the driver into voltages that are 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.
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ENABLE |
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1/4 UT54LVDS032LV |
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DATA |
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RT 100Ω |
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+ |
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INPUT |
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- |
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DATA |
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OUTPUT |
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1/4 UT54LVDS031LV
Figure 3. Point-to-Point Application
The UT54LVDS032LV 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. Both receiver input pins should honor their specified operating input voltage range of 0V to +2.4V (measured from each pin to ground).
2
Receiver Fail-Safe
The UT54LVDS032LV receiver is a high gain, high speed device that amplifies a small differential signal (20mV) to TTL 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 UT54LVDS032LV 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.
2. Terminated Input. If the driver is disconnected (cable unplugged), or if the driver is in a three-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 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 0V 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 (VSS to 2.4V). It is only supported with inputs shorted and no external common-mode voltage applied.
3
ABSOLUTE MAXIMUM RATINGS1 |
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(Referenced to VSS) |
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SYMBOL |
PARAMETER |
LIMITS |
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VDD |
DC supply voltage |
-0.3 to 4.0V |
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VI/O |
Voltage on any pin during operation |
-0.3 to (VDD + 0.3V) |
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Voltage on any pin during cold spare |
-.3 to 4.0V |
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TSTG |
Storage temperature |
-65 to +150°C |
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PD |
Maximum power dissipation |
1.25 W |
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TJ |
Maximum junction temperature2 |
+150°C |
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ΘJC |
Thermal resistance, junction-to-case3 |
10°C/W |
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II |
DC input current |
±10mA |
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Notes:
1.Stresses outside the listed absolute maximum ratings may cause permanent damage to the device. This is a stress rating only,and functional operation of the device at these or any other conditions beyond limits indicated in the operational sections of this specification is not recommended. E xposure to absolute maximum rating conditions for extended periods may affect device reliability and performance.
2.Maximum junction temperature may be increased to +175°C during burn-in and life test .
3.Test per MIL-STD-883, Method 1012.
RECOMMENDED OPERATING CONDITIONS |
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SYMBOL |
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PARAMETER |
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LIMITS |
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VDD |
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Positive supply voltage |
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3.0 to 3.6V |
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TC |
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Case temperature range |
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-55 to +125°C |
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VIN |
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DC input voltage, receiver inputs |
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2.4V |
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DC input voltage, logic inputs |
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0 to VDD for EN, EN |
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