What chips are used in HDMI to LVDS adapters?

What chips are used in HDMI to LVDS adapters

When you crack open an HDMI to LVDS adapter, the core silicon that does the heavy lifting is typically a dedicated bridge chip from a handful of manufacturers. The most common ones you’ll encounter are the ITE IT6613, Analog Devices ADV7611, Texas Instruments TFP401, and Realtek RTD2660 or RTD2556. These chips handle the HDMI signal reception, decoding, and conversion to the parallel or serial LVDS format that LCD panels expect. For instance, the ITE IT6613 is a single-chip HDMI to LVDS bridge that supports up to 1080p at 60Hz, while the RTD2660 is a full-fledged scaler chip that can also adjust resolution and timing. In many budget adapters, you’ll find a MStar or Novatek chipset, like the MST703 or NT68668, which integrates the LVDS transmitter and often includes additional features like OSD (on-screen display) controls. The choice of chip directly impacts the adapter’s resolution cap, color depth, and compatibility with different panel types. For a reliable off-the-shelf solution, you can check out this hdmi to lvds display adapter, which uses a proven chipset for stable performance.

Let’s dig into the specifics. The ITE IT6613 is a popular choice because it’s a low-cost, low-power chip that directly converts HDMI 1.4 signals to single-channel or dual-channel LVDS. It supports 24-bit color depth (16.7 million colors) and resolutions up to 1920x1080@60Hz. The chip includes an integrated HDMI receiver with HDCP 1.4 decryption, so it can handle protected content. On the downside, it doesn’t have a built-in scaler, meaning the input resolution must match the panel’s native resolution, or you’ll get a black screen or distorted image. The Analog Devices ADV7611 is a more robust option, often used in industrial and medical displays. It’s a 12-bit, 170 MHz HDMI receiver that can handle 1080p at 60Hz with deep color (30-bit or 36-bit). It also includes a built-in EDID (Extended Display Identification Data) emulator, which helps with compatibility. However, it’s more expensive and requires external LVDS transmitters like the TI SN75LVDS83B or THC63LVDM83D to complete the conversion.

The Texas Instruments TFP401 is a classic HDMI to LVDS bridge that’s been around for years. It’s a 165 MHz, 24-bit color receiver that supports up to 1080p@60Hz. It’s known for its reliability and is often used in DIY projects and commercial adapters. The chip includes a programmable equalizer for long cable runs and a spread spectrum clock to reduce EMI. But it lacks HDCP support, so it won’t work with Blu-ray players or streaming devices that require encryption. For a more feature-rich solution, the Realtek RTD2660 is a scaler chip that can accept HDMI, VGA, and composite inputs, then output LVDS signals. It includes a microcontroller for OSD menus, backlight control, and panel timing adjustments. This chip is common in universal LCD controller boards, where you can configure it for different panel resolutions via a keypad or software. The RTD2660 supports up to 1920x1080@60Hz and 1366x768@60Hz, but it’s limited to 8-bit color per channel.

Now, let’s talk about the less common but still relevant chips. The MStar MST703 is a single-chip solution that integrates an HDMI receiver, LVDS transmitter, and a scaler. It’s used in many aftermarket adapter boards for laptop LCD panels. It supports resolutions up to 1920x1080@60Hz and includes features like auto-sync detection and panel voltage selection. The Novatek NT68668 is another scaler chip that can handle HDMI 1.4 and output LVDS, with support for up to 2560x1600@60Hz in dual-channel mode. It’s often found in high-end adapters for 4K panels, though it’s actually limited to 2K resolutions due to the HDMI 1.4 bandwidth. The Silicon Image SiI9022 is an older chip that’s still used in some legacy adapters. It supports 1080p@60Hz and includes HDCP, but it’s not as efficient as modern chips.

To give you a clearer picture, here’s a table comparing the key specs of these chips:

Chip	Max Resolution	Color Depth	HDCP Support	Built-in Scaler	Typical Application
ITE IT6613	1920x1080@60Hz	24-bit	Yes (HDCP 1.4)	No	Budget adapters, monitor upgrades
Analog Devices ADV7611	1920x1080@60Hz	12-bit (36-bit deep color)	Yes (HDCP 1.4)	No	Industrial, medical displays
Texas Instruments TFP401	1920x1080@60Hz	24-bit	No	No	DIY projects, commercial adapters
Realtek RTD2660	1920x1080@60Hz	24-bit	No (some versions)	Yes	Universal LCD controller boards
MStar MST703	1920x1080@60Hz	24-bit	Yes (HDCP 1.4)	Yes	Aftermarket laptop panel adapters
Novatek NT68668	2560x1600@60Hz (dual-channel)	24-bit	Yes (HDCP 1.4)	Yes	High-end adapters, 2K panels
Silicon Image SiI9022	1920x1080@60Hz	24-bit	Yes (HDCP 1.4)	No	Legacy adapters, older equipment

Beyond the main bridge chip, the adapter also relies on supporting components. The LVDS transmitter is often integrated into the bridge chip, but in some designs, it’s a separate chip like the TI SN75LVDS83B or THC63LVDM83D. These chips convert the parallel RGB data from the receiver into serial LVDS signals. The SN75LVDS83B is a 24-bit, 5-channel transmitter that supports up to 135 MHz clock, which translates to 1080p@60Hz. The THC63LVDM83D is a 28-bit, 7-channel transmitter that can handle higher resolutions like 1920x1200@60Hz. The EDID EEPROM is another critical component, usually a 24C02 or 24C04 chip that stores the panel’s timing and resolution data. Without it, the HDMI source won’t know what to output. The voltage regulator (like the AMS1117-3.3 or MP1584) powers the chips, and the crystal oscillator (typically 27 MHz or 24 MHz) provides the clock reference.

Let’s talk about real-world performance. In a test with a 15.6-inch 1366x768 LVDS panel, the ITE IT6613 adapter delivered a stable image with no flicker, but it required the HDMI source to output exactly 1366x768. If the source sent 1920x1080, the screen went blank. The RTD2660, on the other hand, could scale the 1080p signal down to 1366x768, but it introduced a slight input lag of about 2-3 frames. For a 21.5-inch 1920x1080 panel, the ADV7611 with a separate LVDS transmitter showed perfect color accuracy and no artifacts, even after a 10-meter HDMI cable. The TFP401-based adapter worked fine with a PC, but it failed to display content from a PS4 due to the HDCP requirement. The Novatek NT68668 adapter handled a 2560x1600 panel at 60Hz, but it needed a dual-channel LVDS cable and a 12V power supply.

Here’s a breakdown of the power consumption and thermal characteristics. The ITE IT6613 draws about 200 mW at idle and 350 mW under load, running at 45°C ambient without a heatsink. The ADV7611 consumes around 500 mW and can reach 60°C, so it often needs a small heatsink. The TFP401 is similar at 400 mW, but it’s more efficient in sleep mode. The RTD2660 is a power hog at 800 mW due to the scaler, and it can hit 70°C, requiring active cooling in some designs. The MStar MST703 and Novatek NT68668 fall in the middle at 600-700 mW. The crystal oscillator typically adds 10-20 mW, and the voltage regulator efficiency drops by 10-15% under load.

Now, let’s look at the connector interfaces. The HDMI input side uses a standard Type A connector with 19 pins, carrying TMDS data, clock, DDC (I2C for EDID), and HPD (hot plug detect). The LVDS output side varies: for single-channel panels, it’s a 20-pin or 30-pin connector (like JAE FI-X30SS or Hirose DF13), while dual-channel panels use a 30-pin or 40-pin connector (like JAE FI-X40SS). The pinout includes differential pairs for data (4 pairs for single-channel, 8 pairs for dual-channel), a clock pair, and power (3.3V or 5V for the panel). The adapter board also has a backlight connector, usually a 6-pin or 8-pin header for LED or CCFL backlights, with pins for enable, PWM dimming, and power (12V or 24V).

In terms of firmware, the chips often have configurable registers. For the ITE IT6613, you can set the LVDS output format (JEIDA or VESA mapping), the clock polarity, and the data mapping. The RTD2660 has a more complex firmware that can be updated via a USB or SPI interface, allowing you to change the OSD language, input source priority, and panel timing. The ADV7611 has a built-in microcontroller that can be programmed via I2C, but it’s usually locked by the manufacturer. The MStar MST703 uses a proprietary firmware that’s flashed via a serial port, and it’s not user-adjustable. The Novatek NT68668 has a similar setup, but some boards allow for firmware updates via a microSD card.

Let’s talk about signal integrity. The HDMI signal is differential, with a voltage swing of 3.3V and a data rate of up to 4.95 Gbps for 1080p@60Hz. The LVDS signal is also differential, with a voltage swing of 1.2V and a data rate of up to 1.2 Gbps per lane. The bridge chip must handle the impedance mismatch (100 ohms for HDMI, 100 ohms for LVDS) and the clock recovery. The ITE IT6613 has a built-in PLL (phase-locked loop) that locks onto the HDMI clock and generates the LVDS clock. The ADV7611 uses a more advanced clock recovery circuit that can handle jitter up to 0.3 UI (unit interval). The TFP401 has a programmable equalizer that can compensate for cable losses up to 20 dB at 1.65 GHz. The RTD2660 includes a de-skew feature that aligns the data lanes to the clock.

For reliability, the chips are rated for different temperature ranges. The ITE IT6613 is commercial grade (0°C to 70°C), while the ADV7611 is industrial grade (-40°C to 85°C). The TFP401 is also industrial grade, but the RTD2660 is only commercial. The MStar MST703 and Novatek NT68668 are typically commercial grade, but some variants are industrial. The MTBF (mean time between failures) for these chips is around 50,000 to 100,000 hours, depending on the operating conditions. The capacitors and connectors are usually the weakest link, with a lifespan of 10,000 to 20,000 hours at 85°C.

Let’s talk about cost. In bulk, the ITE IT6613 costs around $1.50 to $2.00 per chip, making it the cheapest option. The ADV7611 is $4.00 to $6.00, the TFP401 is $3.00 to $4.00, the RTD2660 is $2.50 to $3.50, the MStar MST703 is $2.00 to $3.00, and the Novatek NT68668 is $3.00 to $5.00. The total BOM (bill of materials) for an adapter board ranges from $5.00 for a basic IT6613 design to $15.00 for a full-featured ADV7611 board. The retail price of the adapter is usually 2x to 3x the BOM cost, so a $10 adapter uses a $3 chip, while a $30 adapter uses a $6 chip.

Now, let’s look at some specific examples. The HDMI to LVDS adapter for Raspberry Pi often uses the ITE IT6613 because it’s cheap and works with the Pi’s 1080p output. The adapter for car headrest monitors typically uses the TFP401 because it doesn’t need HDCP. The adapter for medical ultrasound displays uses the ADV7611 for its reliability and deep color support. The universal LCD controller board for laptop panel upgrades uses the RTD2660 or MStar MST703 because of the scaler and OSD features. The adapter for 2560x1600 panels uses the Novatek NT68668 with a dual-channel LVDS output.

Let’s talk about the future. Newer chips like the ITE IT66121 and Analog Devices ADV7619 support HDMI 2.0 and 4K resolutions. The IT66121 can handle 4K@30Hz and outputs LVDS with up to 8 lanes, but it’s still rare in adapters because most LVDS panels are limited to 1080p. The ADV7619 supports 4K@60Hz with 10-bit color, but it requires a more complex PCB design and costs $10+ per chip. The Realtek RTD2795 is a new scaler chip that can handle 4K@60Hz and output eDP or LVDS, but it’s mainly used in monitor controller boards. For now, the chips mentioned earlier dominate the market because of their cost-effectiveness and compatibility with existing panels.

Here’s a table showing the chip-to-panel compatibility:

Panel Resolution	Panel Type	Recommended Chip	LVDS Channel	Notes
1366x768	Single-channel, 6-bit	ITE IT6613, RTD2660	Single	Cheap, works with most laptops
1920x1080	Single-channel, 8-bit	ITE IT6613, TFP401, ADV7611	Single	Common for monitors and TVs
1920x1200	Dual-channel, 8-bit	Novatek NT68668, MStar MST703	Dual

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