DS90C031B LVDS Quad CMOS Differential Line Driver General Description Features The DS90C031B is a quad CMOS differential line driver designed for applications requiring ultra low power dissipation and high data rates. The device is designed to support data rates in excess of 155.5 Mbps (77.7 MHz) utilizing Low Voltage Differential Signaling (LVDS) technology. The DS90C031B accepts TTL/CMOS input levels and translates them to low voltage (350 mV) differential output signals. In addition the driver supports a TRI-STATE function that may be used to disable the output stage, disabling the load current, and thus dropping the device to an ultra low idle power state of 11 mW typical. In addition, the DS90C031B provides power-off high impedance LVDS outputs. This feature assures minimal loading effect on the LVDS bus lines when VCC is not present. The DS90C031B and companion line receiver (DS90C032B) provide a new alternative to high power pseudo-ECL devices for high speed point-to-point interface applications. n n n n n n n n Connection Diagram Functional Diagram > 155.5 Mbps (77.7 MHz) switching rates High impedance LVDS outputs with power-off ± 350 mV differential signaling Ultra low power dissipation 400 ps maximum differential skew (5V, 25˚C) 3.5 ns maximum propagation delay Industrial operating temperature range Pin compatible with DS26C31, MB571 (PECL) and 41LG (PECL) n Conforms to ANSI/TIA/EIA-644 LVDS standard n Offered in narrow body SOIC package n Fail-safe logic for floating inputs Dual-In-Line 10098901 Order Number DS90C031BTM See NS Package Number M16A 10098902 Driver Truth Table Enables Input Outputs EN EN* DIN DOUT+ L H X Z Z All other combinations L L H of ENABLE inputs H H L © 2001 National Semiconductor Corporation DS100989 DOUT− www.national.com DS90C031B LVDS Quad CMOS Differential Line Driver October 2001 DS90C031B Absolute Maximum Ratings Maximum Junction Temperature (Note 1) ESD Rating (Note 7) If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications. Supply Voltage (VCC) +150˚C ≥ 2kV (HBM, 1.5 kΩ, 100 pF) (EIAJ, 0 Ω, 200 pF) ≥ 250V −0.3V to +6V Input Voltage (DIN) −0.3V to (VCC + 0.3V) Enable Input Voltage (EN, EN*) −0.3V to (VCC + 0.3V) Output Voltage (DOUT+, DOUT−) −0.3V to +5.8V Short Circuit Duration (DOUT+, DOUT−) Recommended Operating Conditions Supply Voltage (VCC) Continuous DS90C031BT 1068 mW Derate M Package Typ Max Units +4.5 +5.0 +5.5 V +25 +85 ˚C Operating Free Air Temperature (TA) Maximum Package Power Dissipation @ +25˚C M Package Min −40 8.5 mW/˚C above +25˚C Storage Temperature Range −65˚C to +150˚C Lead Temperature Range Soldering (4 sec.) +260˚C Electrical Characteristics Over supply voltage and operating temperature ranges, unless otherwise specified. (Notes 2, 3) Symbol Parameter Conditions RL = 100Ω (Figure 1) VOD1 Differential Output Voltage ∆VOD1 Change in Magnitude of VOD1 for Complementary Output States VOS Offset Voltage ∆VOS Change in Magnitude of VOS for Complementary Output States VOH Output Voltage High VOL Output Voltage Low VIH Input Voltage High VIL Input Voltage Low II Input Current VIN = VCC, GND, 2.5V or 0.4V Pin Min Typ Max DOUT−, DOUT+ 250 345 450 mV 4 35 |mV| 1.25 1.35 V 5 25 |mV| 1.41 1.60 1.10 RL = 100Ω 0.90 DIN, EN, EN* 1.07 Units V V 2.0 VCC V GND 0.8 V +10 µA −3.5 −5.0 mA −10 ±1 +10 µA −10 ±1 +10 µA −10 ±1 −1.5 −0.8 VCL Input Clamp Voltage ICL = −18 mA IOS Output Short Circuit Current VOUT = 0V (Note 8) IOZ Output TRI-STATE Current EN = 0.8V and EN* = 2.0V, VOUT = 0V or VCC IOFF Power - Off Leakage VO = 0V or 2.4V, VCC = 0V or Open ICC No Load Supply Current Drivers Enabled DIN = VCC or GND 1.7 3.0 mA DIN = 2.5V or 0.4V 4.0 6.5 mA ICCL Loaded Supply Current Drivers Enabled RL = 100Ω (all channels) VIN = VCC or GND (all inputs) 15.4 21.0 mA ICCZ No Load Supply Current Drivers Disabled DIN = VCC or GND EN = GND, EN* = VCC 2.2 4.0 mA DOUT−, DOUT+ VCC V Switching Characteristics VCC = +5.0V, TA = +25˚C (Notes 3, 6, 9) Symbol Parameter Min Typ Max Units 1.0 2.0 3.0 ns 1.0 2.1 3.0 ns Differential Skew |tPHLD – tPLHD| 0 80 400 ps Channel-to-Channel Skew (Note 4) 0 300 600 ps tPHLD Differential Propagation Delay High to Low tPLHD Differential Propagation Delay Low to High tSKD tSK1 www.national.com Conditions RL = 100Ω, CL = 5 pF (Figure 2 and Figure 3) 2 (Continued) VCC = +5.0V, TA = +25˚C (Notes 3, 6, 9) Typ Max Units tTLH Symbol Rise Time Parameter Conditions Min 0.35 1.5 ns tTHL Fall Time 0.35 1.5 ns tPHZ Disable Time High to Z 2.5 10 ns RL = 100Ω, CL = 5 pF (Figure 4 and Figure 5) tPLZ Disable Time Low to Z 2.5 10 ns tPZH Enable Time Z to High 2.5 10 ns tPZL Enable Time Z to Low 2.5 10 ns Min Typ Max Units 0.5 2.0 3.5 ns 0.5 2.1 3.5 ns 900 ps Switching Characteristics VCC = +5.0V ± 10%, TA = −40˚C to +85˚C (Notes 3, 6, 9) Symbol Parameter Conditions tPHLD Differential Propagation Delay High to Low tPLHD Differential Propagation Delay Low to High tSKD Differential Skew |tPHLD – tPLHD| 0 80 0 0.3 tSK1 Channel-to-Channel Skew (Note 4) tSK2 Chip to Chip Skew (Note 5) tTLH Rise Time tTHL Fall Time tPHZ Disable Time High to Z tPLZ Disable Time Low to Z tPZH tPZL RL = 100Ω, CL = 5 pF (Figure 2 and Figure 3) 1.0 ns 3.0 ns 0.35 2.0 ns 0.35 2.0 ns 2.5 15 ns 2.5 15 ns Enable Time Z to High 2.5 15 ns Enable Time Z to Low 2.5 15 ns RL = 100Ω, CL = 5 pF (Figure 4 and Figure 5) 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 except: VOD1 and ∆VOD1. Note 3: All typicals are given for: VCC = +5.0V, TA = +25˚C. Note 4: Channel-to-Channel Skew is defined as the difference between the propagation delay of the channel and the other channels in the same chip with an event on the inputs. Note 5: Chip to Chip Skew is defined as the difference between the minimum and maximum specified differential propagation delays. Note 6: Generator waveform for all tests unless otherwise specified: f = 1 MHz, ZO = 50Ω, tr ≤ 6 ns, and tf ≤ 6 ns. Note 7: ESD Ratings: HBM (1.5 kΩ, 100 pF) ≥ 2kV EIAJ (0Ω, 200 pF) ≥ 250V Note 8: Output short circuit current (IOS) is specified as magnitude only, minus sign indicates direction only. Note 9: CL includes probe and jig capacitance. Parameter Measurement Information 10098903 FIGURE 1. Driver VOD and VOS Test Circuit 3 www.national.com DS90C031B Switching Characteristics DS90C031B Parameter Measurement Information (Continued) 10098904 FIGURE 2. Driver Propagation Delay and Transition Time Test Circuit 10098905 FIGURE 3. Driver Propagation Delay and Transition Time Waveforms 10098906 FIGURE 4. Driver TRI-STATE Delay Test Circuit www.national.com 4 DS90C031B Parameter Measurement Information (Continued) 10098907 FIGURE 5. Driver TRI-STATE Delay Waveform Typical Application 10098908 FIGURE 6. Point-to-Point Application Applications Information the other logic state. The typical output current is a mere 3.4 mA with a minimum of 2.5 mA, and a maximum of 4.5 mA. The current mode requires (as discussed above) that a resistive termination be employed to terminate the signal and to complete the loop as shown in Figure 6. AC or unterminated configurations are not allowed. The 3.4 mA loop current will develop a differential voltage of 340 mV across the 100Ω termination resistor which the receiver detects with a 240 mV minimum differential noise margin neglecting resistive line losses (driven signal minus receiver threshold (340 mV – 100 mV = 240 mV). The signal is centered around +1.2V (Driver Offset, VOS) with respect to ground as shown in Figure 7. Note that the steady-state voltage (VSS) peak-to-peak swing is twice the differential voltage (VOD) and is typically 680 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 between 20 MHz–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 LVDS drivers and receivers are intended to be primarily used in an uncomplicated point-to-point configuration as is shown in Figure 6. This configuration provides a clean signaling environment for the 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 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. The DS90C031B 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 5 www.national.com DS90C031B Applications Information The footprint of the DS90C031B is the same as the industry standard 26LS31 Quad Differential (RS-422) Driver. (Continued) 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. The DS90C031B is electrically similar to the DS90C031, but differs by supporting high impedance LVDS outputs under power-off condition. This allows for multiple or redundant drivers to be used in certain applications. The DS90C031B is offered in a space saving narrow SOIC (150 mil.) package. The fail-safe circuitry guarantees that the outputs are enabled and at a logic ’0’ (the true output is low and the complement output is high) when the inputs are floating. The TRI-STATE function allows the driver outputs to be disabled, thus obtaining an even lower power state when the transmission of data is not required. For additional LVDS application information, please refer to National’s LVDS Owner’s Manual available through National’s website www.national.com/appinfo/lvds. 10098909 FIGURE 7. Driver Output Levels Pin Descriptions Pin No. Name Description 1, 7, 9, 15 DIN 2, 6, 10, 14 DOUT+ Non-inverting driver output pin, LVDS levels 3, 5, 11, 13 DOUT− Inverting driver output pin, LVDS levels Driver input pin, TTL/CMOS compatible 4 EN Active high enable pin, OR-ed with EN* 12 EN* Active low enable pin, OR-ed with EN 16 VCC Power supply pin, +5V ± 10% 8 GND Ground pin Ordering Information Operating Package Type/ Temperature Number −40˚C to +85˚C SOP/M16A www.national.com Order Number DS90C031BTM 6 DS90C031B Typical Performance Characteristics Power Supply Current vs Power Supply Voltage Power Supply Current vs Temperature 10098910 10098911 Power Supply Current vs Power Supply Voltage Power Supply Current vs Temperature 10098912 10098913 Output TRI-STATE Current vs Power Supply Voltage Output Short Circuit Current vs Power Supply Voltage 10098914 10098915 7 www.national.com DS90C031B Typical Performance Characteristics (Continued) Differential Output Voltage vs Power Supply Voltage Differential Output Voltage vs Ambient Temperature 10098916 10098917 Output Voltage High vs Power Supply Voltage Output Voltage High vs Ambient Temperature 10098918 10098919 Output Voltage Low vs Power Supply Voltage Output Voltage Low vs Ambient Temperature 10098920 www.national.com 10098921 8 DS90C031B Typical Performance Characteristics (Continued) Offset Voltage vs Power Supply Voltage Offset Voltage vs Ambient Temperature 10098922 10098923 Power Supply Current vs Frequency Power Supply Current vs Frequency 10098924 10098925 Differential Output Voltage vs Load Resistor Differential Propagation Delay vs Power Supply Voltage 10098926 10098927 9 www.national.com DS90C031B Typical Performance Characteristics (Continued) Differential Propagation Delay vs Ambient Temperature Differential Skew vs Power Supply Voltage 10098929 10098928 Differential Skew vs Ambient Temperature Differential Transition Time vs Power Supply Voltage 10098930 10098931 Differential Transition Time vs Ambient Temperature 10098932 www.national.com 10 DS90C031B LVDS Quad CMOS Differential Line Driver Physical Dimensions inches (millimeters) unless otherwise noted 16-Lead (0.150" Wide) Molded Small Outline Package, JEDEC Order Number DS90C031BTM NS Package Number M16A LIFE SUPPORT POLICY NATIONAL’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT AND GENERAL COUNSEL OF NATIONAL SEMICONDUCTOR CORPORATION. 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