ADCMP551BRQ

Overview

The ADCMP551BRQ is a single-supply, high-speed comparator from Analog Devices Inc., fabricated on the proprietary XFCB process. It features a differential input stage with a common-mode range of −0.2 V to VCCI − 2.0 V and complementary PECL/LVPECL compatible outputs capable of driving 50 Ω transmission lines directly. The device operates within an industrial temperature range of −40°C to +85°C and utilizes dual power supplies (VCCI and VCCO) ranging from 3.135 V to 5.25 V. Key performance metrics include a typical propagation delay of 500 ps at 1 V overdrive, less than 125 ps overdrive dispersion, and an equivalent input rise time bandwidth exceeding 750 MHz.

Feature Summary

• Differential input architecture ensures consistent propagation delay across varying conditions.
• Complementary digital outputs are fully compatible with PECL and 3.3 V LVPECL logic families.
• Integrated latch enable inputs support tracking, track-and-hold, or sample-and-hold operational modes.
• Internal pull-up resistors on latch pins default the device to transparent tracking mode when unconnected.

Applications

• Automatic test equipment
• High speed instrumentation
• Window comparators
• Threshold detection
• Zero crossing detectors

Procurement Notes

Verify the specific ordering suffix 'BRQ' against the manufacturer's current datasheet to confirm package type and tape/reel specifications. Ensure that the required supply voltages for both VCCI and VCCO fall within the specified 3.135 V to 5.25 V range. Confirm that the application environment remains within the -40°C to +85°C industrial temperature limits to maintain guaranteed electrical characteristics.

Selection Notes

Select this component when high-speed signal comparison with minimal timing jitter is required. The differential input stage is suitable for noisy environments where common-mode rejection is critical. The integrated latch functionality allows for precise sampling control in data acquisition systems. Consider the ADCMP552 if programmable hysteresis is needed, or the ADCMP553 for space-constrained applications requiring an 8-lead MSOP package.

Part Context

This part belongs to the ADCMP551/ADCMP552/ADCMP553 family of single-supply, high-speed comparators manufactured by Analog Devices Inc. using the XFCB process. While the ADCMP551 provides a single comparator channel in a 16-lead QSOP package, the family includes the dual-channel ADCMP552 in a 20-lead QSOP and the single-channel ADCMP553 in an 8-lead MSOP. All variants share similar high-speed performance characteristics and output compatibility.

Replacement Considerations

Direct functional substitutes within the same high-speed PECL comparator family include the ADCMP552 and ADCMP553. Verify pinout compatibility and package dimensions before substitution, as the ADCMP552 offers dual channels and programmable hysteresis, while the ADCMP553 uses a smaller 8-lead MSOP package.

FAQ

How does the ADCMP551 handle unused comparator inputs?

Unused inputs should not be left floating due to high internal gain which may cause oscillation. The inputs should be forced into a fixed state by ensuring they are at least one diode drop apart, and the LATCH ENABLE pins must be appropriately connected.

What is the recommended termination for the PECL outputs?

The open-emitter outputs are designed to be terminated through 50 Ω resistors to VCCO − 2.0 V or any other equivalent PECL termination scheme to ensure proper signal integrity and prevent ringing.