LM2506 Low Power Mobile Pixel Link (MPL) Level 0, 18-bit RGB Display Interface Serializer and Deserializer General Description Features The LM2506 device adapts RGB style display interfaces to the Mobile Pixel Link (MPL) Level zero serial link. The LM2506 supports one RGB display at up to 18-bit color depth and 800 X 300 pixels (over 216 Mbps and 13.2 MHz PCLK) is supported. A mode pin configures the device as a Serializer (SER) or Deserializer (DES) so the same chip can be used on both sides of the interface. n RGB Display Interface support up to 800 x 300 1⁄2SVGA formats n MPL-Level 0 Physical Layer using two data and one clock signal n Low Power Consumption n Pinout mirroring enables straight through layout with minimal vias n Level translation between host and display n Auto Power Down on STOP PCLK n Link power down mode reduces quiescent power under < 10 µA n 1.74V to 2.0V core / analog supply voltage range n 1.74V to 3.0V I/O supply voltage range n −30C to 85C Operating temperature range The interconnect is reduced from 22 signals to only 3 active signals with the LM2506 chipset easing flex interconnect design, size constraints and cost. The LM2506 in SER mode resides beside an application, graphics or baseband processor and translates a parallel bus from LVCMOS levels to serial Mobile Pixel Link levels for transmission over a flex cable (or coax) and PCB traces to the DES located near the display module. When the Power_Down (PD*) input is asserted on the SER, the MDn and MC line drivers are powered down to save current. The DES can be controlled by a separate Power_Down input or via a signal from the SER (PDOUT*). The LM2506 implements the physical layer of the MPL Level 0 Standard (MPL-0) and a 150 µA IB current (Class 0). System Benefits n n n n Small Interface Low Power Low EMI Intrinsic Level Translation Typical Application Diagram - Bridge Chips 20125522 © 2006 National Semiconductor Corporation DS201255 www.national.com LM2506 Low Power Mobile Pixel Link (MPL) Level 0, 18-bit RGB Display Interface Serializer and Deserializer August 2006 LM2506 Typical Application Diagram - RGB Mode to Display Driver 20125533 Ordering Information NSID Package Type LM2506GR 49L MicroArray, 4.0 X 4.0 X 1.0 mm, 0.5 mm pitch GRA49A LM2506SQ 40L LLP, 5.0 X 5.0 X 0.8 mm, 0.4 mm pitch SQF40A www.national.com 2 Package ID LM2506 Pin Descriptions - RGB Mode Pin Name No. of Pins Description I/O, Type RGB Serializer RGB Deserializer MPL SERIAL BUS PINS MD[1:0] 2 IO, MPL MPL Data Line Driver MPL Data Receiver MC 1 IO, MPL MPL Clock Line Driver MPL Clock Receiver Ground MPL Ground - see Power/Ground Pins VSSA CONFIGURATION/PARALLEL BUS PINS RGB* 1 I, LVCMOS RGB Mode Input Tie Low M/S* 1 I, LVCMOS Tie High for Serializer (Master) TM 1 I, LVCMOS Test Mode control input Tie Low (normal mode) RM0 1 I, LVCMOS RGB Mode control input zero Tie Low RM1 1 I, LVCMOS RGB Mode control input one Tie Low Tie Low for Deserializer (Slave) CLOCK / POWER DOWN SIGNALS PCLK 1 IO, LVCMOS PCLK input PCLK output PDOUT* 1 O, LVCMOS Power Down Output, L = device in Power Down H = Device active. NA PD* 1 I, LVCMOS Power Down input, L = Powered down (sleep mode) H = active mode PARALLEL INTERFACE SIGNALS D[17:0] 18 IO, LVCMOS RGB Data Bus inputs RGB Data Bus outputs VS 1 IO, LVCMOS Vertical Sync. Input Vertical Sync. Output HS 1 IO, LVCMOS Horizontal Sync. Input Horizontal Sync. Output DE 1 IO, LVCMOS Data Enable Input Data Enable Output PE 1 O, LVCMOS NA Parity Error Output POWER/GROUND PINS VDDA 1 Power Power Supply Pin for the SER PLL and MPL Interface. 1.74V to 2.0V VSSA 1 Ground Ground Pin for the MPL Interface, and analog circuitry. VDDcore 1 Power Power Supply Pin for the digital core. 1.74V to 2.0V VSScore 1 Ground Ground Pin for the digital core. VDDIO 2 Power Power Supply Pin for the parallel interface I/Os. 1.74V to 3.0V VSSIO 2 Ground Ground Pin for the parallel interface I/Os. Vbulk 9 Connect to Ground - uArray Package DAP 1 Connect to Ground - LLP Package Note: I = Input, O = Output, IO = Input/Output. Do not float input pins. 3 www.national.com LM2506 Absolute Maximum Ratings (Note 1) Maximum Package Power Dissipation Capacity at 25˚C If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications. GRA Package Supply Voltage (VDDA) −0.3V to +2.2V Supply Voltage (VDDIO) −0.3V to +3.6V LVCMOS Input/Output Voltage 1.8W Derate SQF Package above 25˚C Min Typ Max −0.3V to VDDA Junction Temperature +150˚C Storage Temperature −65˚C to +150˚C Lead Temperature Soldering, 40 Seconds VDDA to VSSA and VDDcore to VSScore 1.74 1.8 2.0 V VDDIO to VSSIO 1.74 3.0 V 13.3 MHz 85 ˚C PCLK Frequency ESD Ratings: 2 Ambient Temperature ≥ ± 2 kV ≥ ± 200V EIAJ, 0Ω, 200 pF Units Supply Voltage +260˚C HBM, 1.5 kΩ, 100 pF 15mW/˚C Recommended Operating Conditions −0.3V to (VDDIO +0.3V) MPL Input/Output Voltage 15mW/˚C SQF Package −0.3V to +2.2V Supply Voltage (VDD) 1.8W Derate GRA Package above 25˚C −30 25 Electrical Characteristics Over recommended operating supply and temperature ranges unless otherwise specified. (Notes 2, 3) Symbol Parameter Conditions Min Typ Max Units MPL IOLL Logic Low Current (5X IB) 3.67 IB 5.0 IB 6.33 IB µA IOMS Mid Scale Current (Notes 4, 9) 2.1IB 3.0 IB 3.9IB µA IOLH Logic High Current (1X IB) 0.7 IB 1.0 IB 1.4 IB µA IB Current Bias IOFF MPL Leakage Current −2 +2 µA 0.7 VDDIO VDDIO V 150 VMPL = 0.8V µA LVCMOS (1.74V to 3.0V Operation) VIH Input Voltage High Level VIL Input Voltage Low Level VHY Input Hysteresis GND 0.3 VDDIO V VDDIO = 1.74V 150 mV VDDIO = 3.0V 200 mV IIH Input Current High Level IIL Input Current Low Level VOH Output Voltage High Level IOH = −2 mA VOL Output Voltage Low Level IOL = 2 mA Includes IOZ Vin = VDDIO −1 0 +1 µA Vin = GND −1 0 +1 µA 0.75 VDDIO VDDIO V VSSIO 0.2 VDDIO V SUPPLY CURRENT IDD Total Supply Current — Enabled Conditions: MC = 80 MHz, MD = 160 Mbps (Note 5) Supply Current — Enabled 1.8V (Note 6) www.national.com SER DES SER DES VDDIO 20 66 µA VDD/VDDA 5 12 mA VDDIO 4 10 mA VDD/VDDA 6 11 mA VDDIO 10 µA VDD/VDDA 4.7 mA VDDIO 2.3 mA VDD/VDDA 6.2 mA 4 LM2506 Electrical Characteristics (Continued) Over recommended operating supply and temperature ranges unless otherwise specified. (Notes 2, 3) Symbol Parameter Conditions Min Typ Max Units MPL IDDZ Supply Current — Disable TA = 25˚C Power Down Modes Power Dissipation VDD/VDDA SER 8.5 mW DES 15.3 mW VDD/VDDA VDDIO SER Stop Clock VDD/VDDA VDDIO DES PD* = L PD <1 <1 <1 <1 <1 <1 SER PD* = L VDDIO RGB (Note 6) 2 µA 2.2 µA 2 µA 2.2 µA 2 µA 2.2 µA Switching Characteristics Over recommended operating supply and temperature ranges unless otherwise specified. (Note 2) Symbol Parameter Conditions Min Typ Max Units PARALLEL BUS TIMING See tSET Set Up Time tHOLD Hold Time tRISE Rise Time tFALL Fall Time RGB Mode Inputs Figure 11 PCLK Output CL = 15 pF, Figure 2 5 ns 5 ns VDDIO = 1.74V 7 12 ns VDDIO = 3.0V VDDIO = 1.74V 3 7 ns 7 11 VDDIO = 3.0V ns 2 6 ns SERIAL BUS TIMING tDVBC tDVAC Serial Data Valid before Clock (Set Time) DES Input Figure 1 MC = 80MHz (Note 9) Serial Data Valid after Clock (Hold Time) 1.5 ns 1.5 ns POWER UP TIMING t0 SER PLL Lock Counter t1 MC Pulse Width Low t2 MC Pulse Width High t3 MC H-L to Active State tPZXclk Enable Time - Clock Start RGB Mode CLK to PDout* Figure 4 4,096 PCLK cycles 180 MC cycles 180 MC cycles 180 MC cycles 7 PCLK cycles MPL POWER OFF TIMING tPAZ Disable Time to Power Down (Note 8) tPXZclk Disable Time - Clock Stop PCLK to PDOUT* Figure 3 2 7 5 ms PCLK cycles www.national.com LM2506 Recommended Input Timing Requirements Over recommended operating supply and temperature ranges unless otherwise specified. (Note 2) Symbol Parameter Conditions Min Typ Max Units 2 13.3 MHz 75.2 500 ns SER PIXEL CLOCK (PCLK) f Pixel Clock Frequency tCP Pixel Clock Period PCLKDC Pixel Clock Duty Cycle tT Transition Time tSTOPpclk PClock Stop Gap 30 (Note 7) 50 70 % 2 ns 300 ns 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 device should be operated at these limits. The tables of “Electrical Characteristics” specify conditions for device operation. Note 2: Typical values are given for VDDIO = 1.8V and VDD = VDDA = 1.8V and TA = 25˚C. Note 3: Current into a device pin is defined as positive. Current out of device pins is defined as negative. Voltages are referenced to Ground unless otherwise specified. Note 4: MPL Current Threshold is set to be 3XIB by the MPL start up Sequence - this is a functional specification only. Note 5: Total Supply Current Conditions: RGB Mode, worse case data pattern, 13.3MHz PCLK, DES CL = 15pF, TYP VDDIO = VDDA = VDDcore = 1.8V, MAX VDDIO = 3.0V, MAX VDDA = VDDcore = 2.0V. Note 6: Supply Current Conditions: RGB Mode, PRBS case data pattern, 13.3MHz PCLK, DES CL = 15pF, TYP VDDIO = VDDA = VDDcore = 1.8V. Note 7: Maximum transition time is a function of clock rate and should be less than 30% of the clock period to preserve signal quality. Note 8: Guaranteed functionally by the IDDZ parameter. See also Figure 8. Note 9: This is a functional parameter and is guaranteed by design or characterization. Timing Diagrams 20125516 FIGURE 1. Serial Data Valid — DES Input Set and Hold Time 20125518 FIGURE 2. DES Output Rise and Fall Time (PCLK) 20125529 FIGURE 3. Stop Clock Power Down (SER) www.national.com 6 LM2506 Timing Diagrams (Continued) 20125530 FIGURE 4. Stop Clock Power Up (SER) Functional Description SERIAL BUS TIMING Data valid is relative to both edges for a RGB transaction as shown in Figure 6. Data valid is specified as: Data Valid before Clock, Data Valid after Clock, and Skew between data lines should be less than 500ps. BUS OVERVIEW The LM2506 is a dual link SER/DES configurable part that supports an 18-bit RGB Display interface. The MPL physical layer is purpose-built for an extremely low power and low EMI data transmission while requiring the fewest number of signal lines. No external line components are required, as termination is provided internal to the MPL receiver. A maximum raw throughput of 320 Mbps (raw) is possible with this chipset. When the protocol overhead is taken into account, a maximum data throughput of 240 Mbps is possible. The MPL interface is designed for use with common 50Ω to 100Ω lines using standard materials and connectors. Lines may be microstrip or stripline construction. Total length of the interconnect is expected to be less than 20cm. 20125503 FIGURE 6. Dual Link Timing (WRITE) SERIAL BUS PHASES There are three bus phases on the MPL serial bus. These are determined by the state of the MC and MD lines. The MPL bus phases are shown in Table 1. The LM2506 supports MPL Level 0 Enhanced Protocol with a Class 0 PHY. 20125502 FIGURE 5. MPL Point-to-Point Bus TABLE 1. Link Phases MC State MDn State OFF (O) Name 0 0 Link is Off Phase Description Pre-Phase A, I or LU Post-Phase LU ACTIVE (A) A X Data Out LU, A, or I A, I, or O LINK-UP (LU) H - SER initiated Link-Up O A, I, or O Notes on MC/MD Line State: 0 = no current (off) L = Logic Low — The higher level of current on the MC and MD lines H = Logic High — The lower level of current on the MC and MD lines X = Low or High A = Active Clock SERIAL BUS START UP TIMING In the Serial Bus OFF phase, SER transmitters for MD0, MD1 and MC are turned off such that zero current flows over the MPL lines. In addition, both the SER and the DES are internally held in a low power state. When the PD* input pins are de-asserted (driven High) the SER enables its PLL and waits for enough time to pass for its PLL to lock. After the SER’s PLL is locked (t0 = 4,096 PCLK Cycles), the SER will perform an MPL start up sequence. The DES will power up and await the start up sequence from the SER once its PD* input is driven High. 7 www.national.com LM2506 Functional Description Next the SER drives the MC line logically HIGH for 180 MC cycles (t2). The optimized current configuration is held as long as the MPL remains active. Next, the SER drives both the MC and the MD lines to a logical Low for another 180 MC cycles (t3), after which it begins to toggle the MC line at 6X the PCLK rate. The SER will continue to toggle the MC line as long as its PD* pin remains de-asserted (High). At this point, video data is streaming to the DES. (Continued) The MPL start up sequence gives the DES an opportunity to optimize the current sources in its receivers to maximize noise margins. The SER begins the sequence by driving the MC line logically Low for 180 MC cycles (t1). At this point, the DES’s receiver samples the MC current flow and adjusts itself to interpret that amount of current as a logical Low. 20125561 FIGURE 7. Bus Power Up Timing Once power is applied and stable, the PCLK should be applied to the SER. Next the PD* inputs are driven High to enable the SER and DES. The DES PD* input may be driven High first, at the same time, or slightly later than the SER’s PD* input. The SER’s PLL locks to the PCLK and the SER drives the MC line to the 5I (Logic Low) state at point "A" for t1. Next the SER drives the MC line to the 1I (Logic High) state for t2. On the T1 to t2 transition - point "B", the DES calibrates its current to that of the SER to maximize noise margins. Next the SER drives the MC and MD lines to the 5I (logic Low) state for t3. At point "C", video data is now sampled and streamed to the DES. OFF PHASE In the OFF phase, both SER and DES MPL transmitters are turned off with zero current flowing on the MC and MDn lines. Figure 8 shows the transition of the MPL bus into the OFF phase. If an MPL line is driven to a logical Low (high current) when the OFF phase is entered it may temporarily pass through as a logical High (low current) before reaching the zero line current state. www.national.com 20125506 FIGURE 8. Bus Power Down Timing RGB VIDEO INTERFACE The LM2506 is transparent to data format and control signal timing. Each PCLK, data inputs, HS, VS and DE are sampled. A PCLK by PCLK representation of these signals is duplicated on the opposite device after being transferred across the MPL Level-0 interface. The LM2506 uses a multiple range PLL and an on-chip multiplier to accommodate a wide range of display formats. QVGA to 1⁄2SVGA can be supported within the 2 MHz to 13.3 MHz PCLK input range. Pixel Bandwidth = H. X V. X Color Depth X Frames 8 PCLK Rate = Net Bandwidth / 24 The PCLK rate is equal to the net bandwidth divided by the total number of bits. (Continued) Pixel bandwidth is equal to display resolution times color depth times frame rate. Net Bandwidth = (Pixel BW)(24/18)(1.0 + % Blanking) Net bandwidth is equal to the pixel bandwidth times the overhead times the blanking overhead. Format Hor. Pixels Ver. Pixels Color Depth Frames fps Pixel BW Mbps Percent Blanking Net BW Mbps PCLK rate MHz ⁄ SVGA 800 300 18 50 216 10 316 13.2 ⁄ VGA 640 320 16 55 180 10 265 11 12 34 12 ⁄ VGA 320 480 18 55 152 10 223 9.3 QVGA 320 240 18 55 76 20 122 5.1 Other RGB Color Depths the RGB are not used and data is offset toward the upper (MSB) end of the bit fields. Unused inputs should be tied off. When transporting color depth below 18-bit, the 18-bit protocol can be used by offsetting the color data. The LSBs of 201255024 FIGURE 9. 18-bit RGB Display Mode Transaction Parity Error Output for each frame containing an error. The PCLK output can be used to sample the PE bit. SET time is nominally 2 MC cycles and a HOLD time of 1 MC cycle. The serial PE bit is Odd Parity and is based on the RGB, and Control (VS, HS, DE) bits only. See Figure 10. Parity Status is output as a pulse on the Parity Error (PE) output pin (DES) whenever there is a parity error. These pulses could be counted or used by various diagnostic equipment. PE is a high going pulse that is 3 MC cycles long 20125550 FIGURE 10. PE Output Timing SYNCHRONIZATION DETECT AND RECOVERY If a data error or clock slip error occurs over the MPL link, the LM2506 can detect this condition and recover from it. The method chosen is a data transparent method, and has very little overhead because it does not use a data expansion coding method. For the 18-bit color transaction (or frame), it 9 www.national.com LM2506 Functional Description LM2506 Functional Description If however, a clock slip or error occurs, the next N frames will be bad and the F[1:0] field will not be detected properly for each frame after the clock error. In this case, the hysteresis counter will decrement to zero quickly (again where N=4 or 8 pixels). This action shuts down the output data (output PCLK held Low), and initiates a search function for the incrementing sequence. Detecting the Incrementing Sequence (Continued) uses two bits that are already required in the 6-MC cycle transaction. Since double-edge clocking is used with two data signals, adding one clock cycle to the transaction actually adds four bits. One of these bits is absolutely required data enable - thus the others are allocated to Parity and the frame sequence (F[1:0]). Therefore total overhead for each pixel is 3/24 or 12.5% in 18-bit RGB mode. Acquiring synchronization from a random position requires looking only at the MD1 line, as this line contains the incrementing sequence F[1:0]. This is done by examining six two-bit pairs and comparing each pair to an incrementing sequence. A snapshot of the data is first taken and loaded into six two-bit adders. The adders increment by one and then compare the same bit positions in the next 12-bits. If a match is found a flag is set for that bit pair. This same procedure is followed until there is only one flag set. After only one flag is set, the synchronization is tested for the full count of the hysteresis counter (4 or 8 pixels) and then a valid synchronization is declared and pixel data and strobes are again output to the display. HOST SIDE FUNCTION The LM2506 in serializer mode simply increments the two bit field F[1:0] on every pixel or frame transmitted. Therefore every four frames, the pattern will repeat. It is very unlikely that this pattern would be found within the payload data, and if it were found, the probability that it would repeat for many frames becomes infinitely small. DISPLAY SIDE FUNCTION The LM2506 in deserializer mode, upon a normal power up sequence, starts in the proper synchronization. It looks for the incrementing pattern for N (N = 4 or 8) pixels (frames) and finding it, starts to output the pixel gray scale data and timing signals. If a random bit error occurs in the F[1:0] field, the hysteresis counter decrements by one, but the chip continues to output data normally. The next frame will likely recover, incrementing the hysteresis counter back to the maximum and things will continue normally. Likewise if a random bit error occurs in the gray scale data, it only effects that bit and transmission will continue normally on the next frame (pixel). The worst case data bit error would cause a one pixel wide glitch in the HS, VS or DE signals. This would likely cause a visible jump in the display, but it would recover in a maximum of one display frame time. (typically under 20mS) In the best case, this parallel method of detecting sync is very fast. If only one flag exists on the first frame tested, then resynchronization can occur in as little as 6 pixel times (assuming NNE = no new errors). If however, random data emulates an incrementing sequence for several pixels of time, the process can take longer. It is data dependant. It is important to note that a pathological case exists, as it does for most pattern detection methods, where the data can forever emulate this incrementing sequence, when in fact the true F[1:0] is not detected. This F’[1:0] (F prime) may occur for several pixels, but becomes linearly less probable as more and more data passes through the system. 20125526 FIGURE 11. Serializer Mode Input Timing for RGB Interface www.national.com 10 LM2506 Functional Description (Continued) TABLE 2. Serializer Input Timing Parameters for RGB Interface Sym. Parameter Min Typ Max Units tSET Data (RGB, DE, VS or HS) to PCLK - Set Time 5 ns tHOLD PCLK to Data (RGB, DE, VS or HS) - Hold Time 5 ns Note 10: Signal rise and fall times are equal to or less than 20ns Note 11: Measurement of signal timing is made using 0.3 x VDDIO for the low sate and 0.7 x VDDIO for the high state. 20125527 FIGURE 12. Deserializer Mode Output Timing for RGB Interface TABLE 3. Deserializer Output Timing Parameters for RGB Interface Sym. Parameter Min Typ Max Units tDVBC Data Valid before PCLK (rise) PCLK = 2 MHz (Note 9) PCLK = 13.3 MHz 230 30 ns tDVAC Data Valid after PCLK (rise) (Note 9) 230 ns tPCLK Pixel Clock Period PCLK = 2 MHz PCLK = 13.3 MHz ns 30 ns 75.2 500 ns PCLKLOW Pixel Clock Low 50 % PCLKHIGH Pixel Clock High 50 % 11 www.national.com LM2506 POWER DOWN/OFF CONFIGURATION / OPTIONS AND CLOCK STOP Power Up Operation - Upon the application of power to the LM2506, devices configured as a DES activate all outputs. Outputs are held in deasserted states, with all zeros on the data busses until valid data is received from the SER. If PD* is asserted (Low) prior to the application of power, then the part remains in its power down state. LM2506 Features and Operation POWER SUPPLIES The VDDcore and VDDA (MPL and PLL) must be connected to the same potential between 1.74V and 2.0V. VDDIO powers the logic interface and may be powered between 1.74 and 3.0V to be compatible with a wide range of host and target devices. On this device, VDDIO should be powered up before VDDcore/VDDA or at the same time as VDDcore/ VDDAfor proper device configuration. On both the SER and the DES, the PD* pin resets the logic. The PD* pins should be held low until the power supply has ramped up and is stable and within specifications. BYPASS RECOMMENDATIONS Power Down and the use of the PD* Input - When the PD* signal is asserted low, the entire chip regardless of mode, powers down. A Low on the PD* input pin will power down the entire device and turn off the line current to MD0, MD1, and MC. In this state the following outputs are driven to: SER: PDOUT = Low Bypass capacitors should be placed near the power supply pins of the device. Use high frequency ceramic (surface mount recommended) 0.1 µF capacitors. A 2.2 to 4.7 µF Tantalum capacitor is recommended near the SER VDDA pin for PLL bypass. Connect bypass capacitors with wide traces and use dual or larger via to reduce resistance and inductance of the feeds. Utilizing a thin spacing between power and ground planes will provide good high frequency bypass above the frequency range where most typical surface mount capacitors are less effective. To gain the maximum benefit from this, low inductance feed points are important. Also, adjacent signal layers can be filled to create additional capacitance. Minimize loops in the ground returns also for improved signal fidelity and lowest emissions. DES: DATAn = PCLK = Low, VS = HS = DE = PE = Low Multiple configurations for PowerDown are possible with the chipset. These depend on the operating mode and configuration chosen. Two possible applications are shown in Figure 14. RGB Modes are shown in (A) and (B). "A" provides PD* input pins on both devices, this may be common or seperate. In (B), the SER is controlled by the PCLK STOP feature and a PDOUT* pin is provided to control the DES. When using the SER PDOUT* mode, the VDDIO rails of the devices should be the same to meet the PD* input thresholds of the DES. The LM2506 provides a PCLK STOP feature on the SER device. Gating of the pixel clock signal can be used to generate a control signal for the SER to Power down or start up. When a loss of pixel clock is detected (PLL out of lock), the SER PDOUT* pin is driven Low and the SER powers down. When a PCLK is reapplied, the SER powers up, and the PLL locks to the incoming clock signal. After 4,096 cycles (t0), the SER MPL outputs are enabled and the DES is calibrated. Once this is complete (t1 + t2 + t3), data transmission can occur. See Figures 3, 4. The stopping of the pixel clock should be done cleanly. Floating of the PCLK input pin is not recommended. UNUSED/OPEN PINS Unused inputs must be tied to the proper input level — do not float them. Unused outputs should be left open to minimize power dissipation. PHASE-LOCKED LOOP When the LM2506 is configured as a RGB Serializer, a PLL is enabled to generate the serial link clock. The Phaselocked loop system generates the serial data clock at 6X of the input clock. The MC rate must be between 12 and 80 MHz (PCLKs from 2 to 13.3 MHz). MASTER(SER)/SLAVE(DES) SELECTION The M/S* pin is used to configure the device as either a SER or DES device. When the M/S* pin is a Logic High, the Serializer (SER) configuration is selected. The Driver block is enabled for the MC line, and the MD lines. When the M/S* pin is a Logic Low, the Deserializer (DES) configuration is selected. The Receiver block is enabled for the MC line, and the MD lines. www.national.com 12 LM2506 LM2506 Features and Operation (Continued) 20125532 FIGURE 13. Power Down Control Options MPL SWAP FEATURE The LM2506 provides a swap function of MPL MD lines depending upon the state of the M/S* pin. This facilitates a straight through MPL interface design eliminating the needs for via and crossovers as shown on Figure 14. The parallel bus pins are also swapped to facilitate a flow though orientation of parallel bus signals. Application Information SYSTEM CONSIDERATIONS When employing the MPL SER/DES chipset in place of a parallel bus, a few system considerations must be taken into account. VDDIO levels of the Host and SER must be compatible. VDDIO levels of the DES and the Display must be compatible. The LM2506 only supports rising edge clocking, both the Host and Display must be compatible with this. 201255029 FIGURE 14. MPL Interface Layout 13 www.national.com LM2506 Application Information (Continued) Power and Ground - Bumped Package PCB for the microArray package. See also, National’s Application Note AN-1126, Ball Grid Array, for information on land pattern recommendations and escape routing guidelines. Power and ground bump assignments are shown in Figure 15. The nine center balls must be connected ground on the 20125521 FIGURE 15. LM2506 PWR (VDD) and GND (VSS) Bumps (TOP VIEW) FLEX CIRCUIT RECOMMENDATIONS The three MPL lines should generally run together to minimize any trace length differences (skew). For impedance control and also noise isolation (crosstalk), guard ground traces are recommended in between the signals. Commonly a Ground-Signal-Ground (GSGSGSG) layout is used. Locate fast edge rate and large swing signals further away to also minimize any coupling (unwanted crosstalk). In a stacked flex interconnect, crosstalk also needs to be taken into account in the above and below layers (vertical direction). To minimize any coupling locate MPL traces next to a ground layer. Power rails also tend to generate less noise than LVCMOS so they are also good candidates for use as isolation and separation. The interconnect from the SER to the DES typically acts like a transmission line. Thus impedance control and ground returns are an important part of system design. Impedance should be in the 50 to 100 Ohm nominal range for the LM2506. Testing has been done with cables ranging from 40 to 110 Ohms without error (BER Testing). To obtain the impedance, adjacent grounds are typically required ( 1 layer flex), or a ground shield / layer. Total interconnect length is intended to be in the 20cm range, however 30cm is possible at lower data rates. Skew should be less than 500ps to maximize timing margins. GROUNDING While the LM2506 employs three separate types of ground pins, these are intended to be connected together to a www.national.com common ground plane. The separate ground pins help to isolate switching currents from different sections of the integrated circuit (IC). Also required is a nearby signal return (ground) for the MPL signals. These should be provided next to the MPL signals, as that will create the smallest current loop area. The grounds are also useful for noise isolation and impedance control. PCB RECOMMENDATIONS General guidelines for the PCB design: • Floor plan – locate MPL SER near the connector to limit chance of cross talk to high speed serial signals. • Route serial traces together, minimize the number of layer changes to reduce loading. • Use ground lines are guards to minimize any noise coupling (guarantees distance). • Avoid parallel runs with fast edge, large LVCMOS swings. • Also use a GSGSG pinout in connectors (Board to Board or ZIF). • DES device - follow similar guidelines. • • 14 Bypass the device with MLC surface mount devices and thinly separated power and ground planes with low inductance feeds. High current returns should have a separate path with a width proportional to the amount of current carried to minimize any resulting IR effects. LM2506 Application Information (Continued) 20125562 FIGURE 16. MPL Interface Layout 15 www.national.com LM2506 Connection Diagram microArray Package 20125519 TOP VIEW (not to scale) RGB SER Pinout SER 1 2 3 4 5 6 7 A TM RGB* MD0 MC MD1 RM1 M/S* B PCLK PDOUT* RM0 VSSA VDDA PD* HS C R1 R0 Vbulk Vbulk Vbulk VS DE D VDDIO VSSIO Vbulk Vbulk Vbulk VSSIO VDDIO E R2 R3 Vbulk Vbulk Vbulk B4 B5 F R4 R5 G2 VSScore G5 B1 B3 G G0 G1 G3 VDDcore G4 B0 B2 4 5 6 7 RGB DES Pinout DES 1 2 3 A TM RGB* MD1 MC MD0 RM1 M/S* B VS HS RM0 VSSA VDDA PD* PE C B5 DE Vbulk Vbulk Vbulk PCLK R0 D VDDIO VSSIO Vbulk Vbulk Vbulk VSSIO VDDIO E B4 B3 Vbulk Vbulk Vbulk R2 R1 F B2 B1 G4 VSScore G1 R5 R3 G B0 G5 G3 VDDcore G2 G0 R4 www.national.com 16 LM2506 Connection Diagram - LLP Package 20125553 TOP VIEW — (not to scale) TABLE 4. RGB Mode Pad Assignment Pin # SER DES Pin # SER DES 1 M/S* 21 G0 B0 2 RM1 22 G1 G5 3 VDDA 23 G2 G4 4 24 G3 5 VSSA 25 VSScore 6 MC 26 VDDcore 7 MD1 MD0 27 G4 8 RM0 28 G5 G1 9 RGB* 29 B0 G0 HS 30 B1 R5 10 MD0 MD1 PDOUT* 11 TM G2 31 B2 R4 12 PCLK VS 32 B3 R3 13 R0 DE 33 B4 R2 14 R1 B5 34 B5 15 VSSIO 16 35 VDDIO R1 VSSIO 36 VDDIO 17 R2 B4 37 18 R3 B3 19 R4 B2 20 R5 B1 40 PD* DAP GND DAP GND DE R0 38 VS PCLK 39 HS PE Note: Pins are different between SER and DES configurations. 17 www.national.com LM2506 Physical Dimensions inches (millimeters) unless otherwise noted 49L MicroArray, 0.5mm pitch Order Number LM2506GR NS Package Number GRA49A 40L LLP, 0.4mm pitch Order Number LM2506SQ NS Package Number SQF40A www.national.com 18 National does not assume any responsibility for use of any circuitry described, no circuit patent licenses are implied and National reserves the right at any time without notice to change said circuitry and specifications. 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