The term **556-R** typically refers to a high-precision, low-profile **Resistor Network** (often produced by manufacturers like Bourns). It is designed to save space on Printed Circuit Boards (PCBs) by integrating multiple resistors into a single package. --- ### 1. General Specifications The 556 series usually follows the Single In-line Package (SIP) format. Below are the standard technical characteristics: | Feature | Typical Specification | | :--- | :--- | | **Package Type** | SIP (Single In-line Package) | | **Power Rating** | 0.125W to 0.250W per resistor | | **Tolerance** | ±1%, ±2%, or ±5% | | **Operating Temp** | -55°C to +125°C | | **Resistance Range** | 10 Ohms to 1 Megohm | --- ### 2. Internal Configurations The "556" series resistors come in different internal circuit layouts. The most common are: * **Isolated (Circuit Type A):** Each resistor is independent with its own two pins. * **Bussed (Circuit Type B):** One end of every resistor is connected to a common pin (usually Pin 1). This is used for "pull-up" or "pull-down" applications. * **Dual Terminator (Circuit Type C):** Specifically designed for impedance matching and line termination. --- ### 3. Part Number Breakdown (Example) If you see a part number like **4308R-101-556**, it is interpreted as follows: 1. **4308R:** The series identifier (8-pin molded SIP). 2. **101:** The circuit type (e.g., Bussed). 3. **556:** The resistance value. * **55** = The first two significant digits. * **6** = The number of zeros (multiplier). * **Result:** 55,000,000 Ohms (55 MΩ). *Note: Most standard values use a 3-digit code where 556 would be unusually high; double-check if the "R" indicates a decimal or a specific tolerance series.* --- ### 4. Applications * **Digital Logic:** Providing pull-up resistors for microcontrollers. * **LED Current Limiting:** Driving multiple LEDs with a single component. * **Space-constrained PCBs:** Replacing 4 to 12 individual SMD resistors. ---