Differential Video Interface Chipset

The MAX9546/MAX9547 differential interface chipset converts single-ended voltages to differential voltages for transport and then converts back to single-ended voltages. These devices eliminate costly, bulky, single-ended coaxial cables with inexpensive, readily available, differential shielded (ScTP) or unshielded (UTP) twisted pairs. The fault detection of the MAX9546 and loss-of-signal detection of the MAX9547 allow proactive and speedy diagnosis, such as identifying failures in the manufacturing stage and troubleshooting equipment at repair facilities. The MAX9546/MAX9547 are low-cost, convenient solutions for transporting CVBS/FBAS analog video signals (PAL or NTSC) through hostile environments.

The MAX9546 driver converts the single-ended input into a differential output with a 6dB fixed gain to drive a back-terminated, DC-coupled differential video output to unity gain. This DC connection allows the detection of a short-circuit condition at the differential outputs. The active-low FAULT output indicates a short-circuit condition including a short to a high battery condition (VBAT = +16V) or ground.

The MAX9547 receiver converts the differential signal from the MAX9546 into a single-ended signal. Like the MAX9546 output, the MAX9547 input survives a short to a high battery condition or ground. The MAX9547 receiver loss-of-signal output (active-low LOS) operates by detecting the H-Sync and thus can support both monochrome and color video signals. The MAX9547 gain is set with an external impedance between ZT+ and ZT-.

The MAX9546/MAX9547 operate from a 7.5V to 10V single supply. Both devices include ±15kV ESD Human Body Model (HBM) protection. The MAX9546/MAX9547 are offered in a thermally enhanced 8-pin SO package and specified over the -40°C to +85°C extended temperature range.

Applications

* Avionics/In-Flight Entertainment * Security/CCTV Video

* Fault Detection (MAX9546)

* Loss-of-Signal Detection (MAX9547)

* Tolerate ±2V Ground-Level Shift between Source and Load

* ±15kV ESD Protection (Human Body Model)

* ±8kV—IEC 1000-4-2 Contact Discharge

* ±15kV—IEC 1000-4-2 Air-Gap Discharge

* Preset 6dB Gain (MAX9546)

* Variable Receiver Gain (MAX9547)

* 7.5V to 10V Single-Supply Operation