## Overview of ADCMP562 The **ADCMP562** is a high-speed, dual ultra-fast voltage comparator manufactured using a proprietary Analog Devices process. It is designed for applications requiring precise timing and high-speed signal processing. ### Key Specifications | Feature | Specification | | :--- | :--- | | **Propagation Delay** | 700 ps (typical) | | **Input Type** | Differential | | **Output Logic** | PECL (Positive Emitter-Coupled Logic) | | **Supply Voltage** | +5.0 V and -5.2 V (Dual Supply) | | **Package** | 20-lead QSOP | | **Operating Temperature** | -40°C to +85°C | --- ### Internal Functional Blocks The ADCMP562 consists of several critical electronic stages that allow it to achieve sub-nanosecond speeds: 1. **Input Stage:** Features high-impedance differential inputs with a wide common-mode range. It is designed to handle fast-rising edges with minimal overdrive dispersion. 2. **Latch Enable (LE) Circuitry:** This allows the comparator to function in "track" mode or "latch" mode. When latched, the output is held constant regardless of input changes, which is essential for sample-and-hold operations in high-speed data acquisition. 3. **Output Driver:** Specifically designed to drive **PECL** termination. PECL outputs are used to maintain signal integrity over high-frequency transmission lines (typically 50 $\Omega$). --- ### Pin Configuration & Critical Components | Pin Name | Function | Description | | :--- | :--- | :--- | | **VCC / VEE** | Power Supply | Positive (+5V) and Negative (-5.2V) rails. | | **INA+ / INA-** | Inputs | Differential input pair for Comparator A. | | **QA / /QA** | Outputs | Complementary PECL outputs. | | **LEA / /LEA** | Latch Control | Differential latch enable inputs. | | **VT** | Termination | Termination voltage pin for internal biasing. | --- ### Typical Application Circuit To use the ADCMP562 effectively, proper termination of the PECL outputs is required to prevent signal reflection. ```c // Conceptual high-speed setup // 1. Connect VCC to +5.0V with 0.1uF decoupling capacitor. // 2. Connect VEE to -5.2V with 0.1uF decoupling capacitor. // 3. Terminate QA and /QA outputs through 50 Ohm resistors to VCC - 2V. // 4. Ensure ground plane is solid to minimize EMI. ``` --- ### Applications * **Automatic Test Equipment (ATE):** Precise timing measurement. * **High-speed Instrumentation:** Pulse spectroscopy and logic analyzers. * **Clock and Data Restoration:** Cleaning up jittery high-speed signals. * **Window Comparators:** Used in pairs for signal envelope detection.