The **ADP3605ARZ-R7** is a high-performance, regulated switched-capacitor voltage inverter manufactured by Analog Devices. It is primarily used to generate a negative voltage from a positive input supply without the need for an inductor. --- ### 1. Key Technical Specifications | Parameter | Specification | | :--- | :--- | | **Input Voltage Range** | 3.0V to 6.0V | | **Output Voltage** | Regulated -3.0V (Adjustable with external resistors) | | **Output Current** | Up to 120 mA | | **Switching Frequency** | 250 kHz | | **Package Type** | SOIC_N (8-lead) | | **Operating Temperature** | -40°C to +85°C | --- ### 2. Functional Components and Features #### A. Regulated Output Unlike standard "charge pump" inverters that simply double the input voltage negatively ($V_{out} = -V_{in}$), the ADP3605 features an internal linear regulator. This ensures the output remains stable even if the input voltage fluctuates or the load changes. #### B. Charge Pump Architecture The device uses a switched-capacitor mechanism. It charges an external capacitor ($C_{pump}$) and then flips its polarity to transfer the charge to the output capacitor ($C_{out}$). * **No Inductors:** This reduces EMI (Electromagnetic Interference) and saves board space. * **Efficiency:** High conversion efficiency for low-power applications. #### C. Shutdown Mode The chip includes a logic-controlled shutdown pin. When pulled low, the device enters a low-power state, consuming less than **2μA**, which is critical for battery-powered electronics. --- ### 3. Pin Configuration | Pin Number | Name | Description | | :--- | :--- | :--- | | 1 | **OUT** | Regulated Negative Output Voltage. | | 2 | **$C_{P-}$** | Negative terminal for the pump capacitor. | | 3 | **GND** | Ground reference. | | 4 | **SHDN** | Shutdown Control (Active High). | | 5 | **SENSE/ADJ** | Feedback input to regulate the output voltage. | | 6 | **$C_{P+}$** | Positive terminal for the pump capacitor. | | 7 | **$V_{IN}$** | Positive Supply Input. | | 8 | **NC** | No Connection. | --- ### 4. Typical Application Circuit To use the ADP3605 in a standard configuration, you need minimal external components: ```markdown 1. Input Capacitor (Cin): 10μF (Ceramic) 2. Pump Capacitor (Cpump): 4.7μF (Ceramic) 3. Output Capacitor (Cout): 10μF (Ceramic) 4. Feedback Resistors: (Optional, only if adjusting from the default -3V) ``` ### 5. Common Applications * **Operational Amplifier Supplies:** Providing a negative rail for dual-supply Op-Amps. * **Data Acquisition:** Powering ADCs and DACs that require bipolar inputs. * **LCD Bias:** Generating negative contrast voltages for displays. * **Portable Instruments:** Where space for bulky inductors is unavailable. ---