Overview
The LMH0034MAX is a high-performance adaptive cable equalizer designed by Texas Instruments, although it is often associated with National Semiconductor due to historical context. This integrated circuit is specifically tailored for equalizing data transmitted over cable, particularly in applications that adhere to SMPTE 292M and SMPTE 259M standards. It supports data rates from 125 Mbps to 1.485 Gbps, making it suitable for both standard definition (SD) and high definition (HD) serial digital video.
Key Specifications
| Parameter | Min | Max | Units | |
|---|---|---|---|---|
| VCMIN Input Common Mode Voltage | 1.9 | - | - | V |
| VSDI Input Voltage Swing | 720 | 800 | 950 | mVp-p |
| VCMOUT Output Common Mode Voltage | VCC - V | VSDO/2 | - | V |
| VSDO Output Voltage Swing | - | - | 750 | mVp-p (50Ω load, differential) |
| CLI DC Voltage | 0m cable: 2.5 V | - | Max cable: 1.9 V | V |
| MUTEREF DC Voltage | 0.7 | 1.3 | - | V |
| CD/MUTE Output Voltage | Carrier not present: 2.6 V | - | Carrier present: 0.4 V | V |
| ICC Supply Current | 63 | 77 | - | mA |
| Voltage - Supply | 3.135 | - | 3.465 | V |
| Package / Case | - | - | 16-SOIC (0.154", 3.90mm Width) | - |
| Mounting Type | - | - | Surface Mount | - |
Key Features
- Supports SMPTE 292M and SMPTE 259M standards, with data rates from 125 Mbps to 1.485 Gbps.
- Equalizes up to 200 meters of Belden 1694A cable at 1.485 Gbps or up to 400 meters at 270 Mbps.
- Manual Bypass, Cable Length Indicator, and Output Mute with a Programmable Threshold.
- Single-Ended or Differential Input and 50Ω Differential Outputs.
- Single 3.3V Supply Operation and typical power consumption of 208 mW.
- DC Restoration to handle pathological data conditions, which can be bypassed for low data rate applications.
- Combined carrier detect and output mute pin to mute the output when no signal is present.
- Form-fit-function compatible with the Gennum GS1524 and GS1524A.
Applications
- SMPTE 292M and SMPTE 259M compliant applications.
- Serial digital video transmission systems, including both standard definition (SD) and high definition (HD) video.
- DVB-ASI at 270 Mbps.
- Professional video equipment, broadcast systems, and other high-speed data transmission applications.
Q & A
- What is the primary function of the LMH0034MAX?
The LMH0034MAX is an adaptive cable equalizer designed to equalize data transmitted over cable, particularly in SMPTE 292M and SMPTE 259M compliant applications.
- What are the supported data rates for the LMH0034MAX?
The LMH0034MAX supports data rates from 125 Mbps to 1.485 Gbps.
- How much cable can the LMH0034MAX equalize?
The LMH0034MAX can equalize up to 200 meters of Belden 1694A cable at 1.485 Gbps or up to 400 meters at 270 Mbps.
- What input types does the LMH0034MAX support?
The LMH0034MAX supports both single-ended and differential input drive.
- What is the power supply requirement for the LMH0034MAX?
The LMH0034MAX operates on a single 3.3V supply.
- Does the LMH0034MAX have DC restoration capabilities?
Yes, the LMH0034MAX includes a DC restoration circuit to handle pathological data conditions, which can be bypassed for low data rate applications.
- What is the purpose of the Cable Length Indicator (CLI) in the LMH0034MAX?
The CLI provides a voltage inversely proportional to the cable length being equalized.
- Can the LMH0034MAX be used in place of other equalizers?
Yes, the LMH0034MAX is form-fit-function compatible with the Gennum GS1524 and GS1524A.
- How does the output mute function work in the LMH0034MAX?
The LMH0034MAX has a combined carrier detect and output mute pin that mutes the output when no signal is present, with a programmable mute reference.
- What is the typical power consumption of the LMH0034MAX?
The typical power consumption of the LMH0034MAX is 208 mW with a 3.3V supply.
