Building DVI to HDMI Adapter Circuit Step-by-Step Wiring Guide

dvi to hdmi schematic diagram

Start with a TMDS signal adapter circuit using the TFP401 or TFP410 receiver IC for accurate data translation. These chips handle 24-bit color depth at resolutions up to 1920×1200 (WUXGA) without frame drops. Connect the 29-pin digital video port output pins 1–24 to the receiver’s parallel inputs, ensuring proper ground referencing (pins 25–29).

For the output stage, integrate a Silicon Image SiI9022A transmitter. Map the receiver’s parallel outputs (8-bit data per channel) to the transmitter’s inputs, preserving pixel clock synchronization via the differential pair (pins 12–13 on the SiI9022A). Add a 100nF ceramic capacitor between the transmitter’s AVcc (pin 9) and ground to filter high-frequency noise.

Include a 3.3V LDO regulator (e.g., AP2112K) to power the transmitter, isolating it from the receiver’s 5V rail. Route the hot-plug detect signal (pin 19) through a 1kΩ pull-up resistor to 5V to enable automatic sync detection. Test signal integrity using an oscilloscope on the clock+ and data+ lines–ensure rise/fall times under 200ps for stable transmission.

For audio passthrough, wire the S/PDIF line from the source’s pin 28 to the transmitter’s I²S input (pins 4–7). Configure the SiI9022A via I²C (pins 55–56) for 16-bit/48kHz audio output by setting register 0x1A to 0x02. Verify functionality by monitoring the CEC line (pin 14) for device handshake pulses.

Minimize EMI by using a four-layer PCB with dedicated ground planes for digital and analog sections. Place 0Ω resistors between planes near the transmitter for noise suppression. Avoid daisy-chaining power traces–route Vcc and GND as star topologies. For custom resolutions, modify the EDID EEPROM (e.g., 24LC02) with extended timing descriptors to match the display’s native mode.

Building a Digital Visual Interface to High-Definition Multimedia Adapter

Use a TMDS-compatible signal converter IC like the Silicon Image SiI164 or Parade PS8612 as the core component. These chips handle 24-bit RGB data streams up to 165 MHz, ensuring 1080p resolution support without compression. Connect the transmitter’s output pairs directly to the receiver’s input lanes–avoid longues or splitters, as they introduce signal skew. Power the IC with a stable 3.3V source, decoupled with a 0.1µF ceramic capacitor per pin to suppress high-frequency noise.

Match the impedance of the differential pairs to 100Ω ±10%. Route traces on a 4-layer PCB with controlled impedance, keeping signal layers adjacent to solid ground planes. Maintain trace lengths within 5% of each other to prevent timing mismatches. For rev.B and later, include the Consumer Electronics Control channel by adding a bidirectional voltage translator like the TXS0108E to bridge the 3.3V logic with 5V-compatible pins. Skip this step only if the host device lacks pin 16 functionality.

Pin Mapping Function Adapter Side Multimedia Side
1, 2, 9, 10 TMDS Data0+, Data0− + (green) 18, 17
3, 4, 11, 12 TMDS Data1+, Data1− − (green) 20, 19
5, 6, 13, 14 TMDS Data2+, Data2− + (blue) 22, 21
C1, C2, C3, C4 TMDS Clock+, Clock− Clock 23, 24

Terminate unused multimedia interface pins with 47kΩ pull-down resistors to prevent floating inputs. For hot-plug detection, connect a 1kΩ resistor between the 5V pin and the +5V rail of the source. Add a Schottky diode like the BAT54 to block reverse current during unpowered connections. Include ESD protection on all data lines using transient voltage suppression diodes rated for 8kV contact discharge per IEC 61000-4-2.

Verify signal integrity with an oscilloscope before finalizing the PCB. Probe the clock pair for a clean 50% duty cycle waveform at the target pixel clock frequency. Data lanes should exhibit eye diagrams with >400 mV swing and 3 m), add a redriver chip like the TI TMDS171 to amplify the signal, ensuring compliance with HDCP requirements.

Ground the adapter’s metal shield to the PCB’s ground plane via a low-inductance path. Use a star grounding topology to minimize loop currents. For devices requiring audio embedding, inject I²S signals into the converter IC’s auxiliary pins–check the datasheet for clock speed limits, typically 48 kHz or 96 kHz. Omit audio support if the source lacks the necessary encoding hardware.

Test the circuit with multiple sources–validate 720p60, 1080p30, and 1080p60 resolutions. Check for color depth consistency across 8-bit, 10-bit, and 12-bit modes if supported. EDID emulation is optional but recommended: program an I²C EEPROM with a 256-byte table to advertise supported resolutions. Store the binary on a 24LC02 chip, powered by the source’s 5V rail.

Label the PCB clearly: mark pin 1 alignment notches, voltage rails, and test points for debugging. Silkscreen reference designators next to components for easier repair. For mass production, panelize the design with breakaway tabs to streamline assembly. Use lead-free solder and ENIG surface finish for reliability under thermal cycling.

Key Parts for Signal Interface Adaptation

Start with a high-quality TMDS transceiver IC like the TFP401 or ADV7611 for reliable digital transmission. These chips handle the differential pair decoding and encoding, ensuring signal integrity across the entire range of 24-bit color depth without introducing artifacts. Verify the chip supports resolutions up to 2560×1440 at 60Hz or higher if targeting modern displays, as underspec’d ICs will clip or distort transitions at bandwidth thresholds.

Passive components must match trace impedance precisely: 0.1µF ceramic capacitors (X7R dielectric) for decoupling, 33Ω series resistors on the TMDS pairs to suppress ringing, and 0Ω jumpers for configuration flexibility. Use 50Ω controlled-impedance traces (microstrip or stripline) on a four-layer PCB with a dedicated ground plane; two-layer boards risk crosstalk above 1.65Gbps. Include ESD protection diodes (e.g., PESD5V0S1BA) on all external connector pins to prevent transient damage from hot-plug events.

Connector and Physical Layer Considerations

Select a Type-A receptacle (19-pin, female) with a robust metal shell and gold-plated contacts rated for 10,000 insertion cycles. The source-side plug demands a compliant 29-pin male connector, typically with 1.27mm pitch; non-standard pinouts risk signal mismatch. Ensure the cable assembly uses twisted pairs for the four TMDS channels and a separate #5 shield drain wire bonded to the connector shell at both ends to minimize EMI. For cable length exceeding 1.5 meters, incorporate redriver ICs (e.g., TUSB1046) to amplify signals degraded by insertion loss.

EDID memory (24C02 or equivalent) must store the display’s VESA-compliant descriptor block; failure to include it forces fallback to 640×480 at 60Hz. Program the EEPROM with the target resolution, audio capabilities (if applicable), and HDCP keys when content protection is mandatory. Add a 1kΩ pull-up resistor on the I²C lines (SCL/SDA) to 3.3V, and insert a 3.3V LDO regulator (e.g., AP2112K) if the interface lacks a stable supply. For audio transport, route the SPDIF/I²S lines to an onboard codec or breakout header, ensuring impedance matching with 75Ω coax or 3.3V LVTTL.

Power Delivery and Thermal Mitigation

Design the power plane to deliver 3.3V at 500mA min, sourced from either a dedicated buck converter or the display’s auxiliary feed. Thermal pads beneath the TMDS IC and redriver should connect to a copper pour (minimum 2oz) spanning at least 5cm² to dissipate ~1.2W under full load. Avoid shared ground vias for high-speed signals; instead, use stitching vias every 5mm around the perimeter to contain return currents. Validate the layout with eye-diagram testing at 2.97Gbps; margins below 100mV vertical opening or 0.3UI horizontal jitter indicate marginal performance requiring trace tuning or IC replacement.

Step-by-Step Wiring Guide for Passive Digital Visual to High-Definition Media Converter

Begin by identifying pin assignments on both interfaces: the 24-pin digital video output connector carries 19 functional lines, while the 19-pin multimedia link includes 16 signal paths and 3 grounding contacts. Use a multimeter to verify the continuity of each wire, ensuring none exceed 0.5 ohms resistance for reliable signal integrity. Cut a shielded cable to 15 cm length to minimize interference–longer runs risk attenuation, particularly for TMDS pairs (pins 1-8, 9-16, 17-24 on the source side).

Critical Connections

  • Match TMDS data channels directly: source pins 1→2 (pair 0), 3→4 (pair 1), 9→10 (pair 2). Cross-check with a continuity tester–mismatched pairs cause color artifacts.
  • Ground all unused pins (source pins 11, 12, 15, 23) to the target’s pin 17 to prevent floating voltages.
  • Link the +5V power line (source pin 14) to target pin 18 to enable EDID handshake; omit this step for non-PnP devices.
  • For audio support, route the CEC signal (source pin 13) to target pin 13–confirm the sink device supports ARC if bidirectional audio is required.

Solder each connection under 300°C for under 3 seconds to avoid damaging the thin 0.1 mm enameled wire insulation. Wrap each pair in aluminum foil, then bundle the entire assembly in copper braid, grounding both ends to the connector shells to suppress EMI. Test with a 720p or 1080p signal before final assembly–intermittent distortion indicates a cold solder joint or improper shielding.

Pinout Mapping Between Digital Video Link and High-Definition Multimedia Interface Connectors

Use direct wire-to-wire connections for 18 of the 24 pins shared between single-link TMDS and Type A multimedia interfaces. Pins 1-9 (TMDS Data2+ to Data0-) map identically to pins 1-9 on the multimedia plug, while the clock pair (pins 14-15) transfers to pins 10-11. Ground references at pins 17-18 and 23-24 match pins 17-18 on the output connector. Exclude pins 10-13, 19-22, and C1-C5–these carry second-link data, analog signals, or power. Verify continuity with a multimeter before powering to prevent signal degradation.

  • Pin 1 (TMDS Data2+) → Pin 1 (HDMI Data2+)
  • Pin 2 (TMDS Data2-) → Pin 2 (HDMI Data2-)
  • Pin 3 (TMDS Data1+) → Pin 3 (HDMI Data1+)
  • Pin 4 (TMDS Data1-) → Pin 4 (HDMI Data1-)
  • Pin 5 (TMDS Data0+) → Pin 5 (HDMI Data0+)
  • Pin 6 (TMDS Data0-) → Pin 6
  • Pin 7 (Ground) → Pin 7 (Shared return)
  • Pin 8 (N/C) → Pin 8 (Reserved)
  • Pin 9 (TMDS Clock+) → Pin 9
  • Pin 14 (TMDS Clock-) → Pin 10
  • Pin 15 (Ground) → Pin 11
  • Pin 17 (Ground) → Pin 17
  • Pin 18 (Ground) → Pin 18
  • Pin 23 (Ground) → Pin 19
  • Pin 24 (Ground) → Pin 16 (Hot plug detect)