## Overview of TS391BL-AF5-R The **TS391BL-AF5-R** is a low-power, single-channel voltage comparator designed for efficiency and versatility in low-voltage systems. It is commonly produced by manufacturers like **Unisonic Technologies (UTC)** and is functionally similar to the industry-standard LM391. --- ### 1. Key Technical Specifications | Parameter | Value / Detail | | :--- | :--- | | **Type** | Single Voltage Comparator | | **Supply Voltage (Single)** | 2.0V to 36V | | **Supply Voltage (Dual)** | ±1.0V to ±18V | | **Low Supply Current** | 0.8mA (typical) | | **Output Type** | Open Collector (requires pull-up resistor) | | **Package Type** | SOT-25 / SOT-23-5 | | **Operating Temperature** | -40°C to +85°C | --- ### 2. Functional Characteristics * **Wide Supply Range:** It can operate on a wide range of voltages, making it compatible with both 3.3V/5V digital logic and higher-voltage analog systems. * **Open Collector Output:** The output is an NPN transistor with an open collector. This allows the designer to level-shift the output voltage to any level (up to 36V) regardless of the chip's supply voltage, simply by choosing the appropriate pull-up resistor voltage. * **Low Input Bias Current:** The input stage is designed to have very low current draw, which minimizes errors when sensing high-impedance sources. * **Common-Mode Input Range:** The input voltage range includes ground (0V), even when operating from a single power supply. --- ### 3. Pin Configuration (SOT-25/23-5) | Pin Number | Symbol | Function | | :--- | :--- | :--- | | 1 | OUT | Output (Open Collector) | | 2 | VCC | Positive Power Supply | | 3 | GND | Ground (Negative Power Supply) | | 4 | IN- | Inverting Input | | 5 | IN+ | Non-inverting Input | --- ### 4. Typical Applications 1. **Level Translators:** Due to the open-collector output, it can bridge circuits operating at different voltages (e.g., 3V logic to 12V logic). 2. **Zero-Crossing Detectors:** Used in AC power monitoring to detect when the sine wave crosses 0V. 3. **Battery Monitoring:** Detecting low-voltage conditions in portable electronics due to its low power consumption. 4. **Limit Comparators:** Checking if a sensor voltage is within a specific window/threshold. --- ### 5. Circuit Design Tip Since the **TS391BL-AF5-R** has an open-collector output, **it cannot drive a load "High" by itself.** You must connect a resistor (typically 1kΩ to 10kΩ) between the `OUT` pin and the desired high-level voltage source (V_pullup).