The **ADM7170ACPZ-4.2-R7** is a high-performance, CMOS low dropout (LDO) linear regulator produced by Analog Devices. It is designed specifically for high-performance analog and mixed-signal circuits that require high power supply rejection and low noise. --- ### ## Technical Specifications | Parameter | Value / Description | | :--- | :--- | | **Manufacturer** | Analog Devices Inc. | | **Input Voltage Range** | 2.3 V to 6.5 V | | **Fixed Output Voltage** | 4.2 V | | **Maximum Output Current** | 500 mA | | **Low Noise** | 5 μV rms (100 Hz to 100 kHz) | | **PSRR** | 60 dB at 1 kHz; 40 dB at 1 MHz | | **Dropout Voltage** | 42 mV (typical at 500 mA load) | | **Package** | 8-Lead LFCSP (3mm x 3mm) | | **Operating Temp** | -40°C to +125°C | --- ### ### Key Electronic Features 1. **Ultra-Low Noise:** The 5 μV rms noise figure makes it ideal for powering sensitive components like VCOs (Voltage Controlled Oscillators), ADCs, and DACs where power supply noise can degrade signal integrity. 2. **High PSRR:** It effectively filters out high-frequency ripple from switching power supplies, ensuring a stable output even in noisy environments. 3. **Fast Transient Response:** The device is optimized for excellent response to line and load transients, meaning it can handle sudden changes in demand or input fluctuations without significant voltage drops. 4. **Soft Start Function:** It includes an internal soft-start feature that limits inrush current during startup, protecting the rest of the circuitry. 5. **Precision Enable:** The enable pin has a precise threshold, allowing the device to be used for power sequencing in multi-rail systems. --- ### ### Pin Configuration (8-Lead LFCSP) | Pin No. | Name | Function | | :--- | :--- | :--- | | 1 | VOUT | Regulated Output Voltage (4.2 V) | | 2 | VOUT | Regulated Output Voltage | | 3 | SENSE | Feedback input (Connect to VOUT) | | 4 | GND | Ground | | 5 | EN | Enable Input (High = On, Low = Off) | | 6 | SS | Soft Start (Capacitor to GND) | | 7 | VIN | Input Voltage | | 8 | VIN | Input Voltage | | EP | Pad | Exposed Pad (Connect to GND for thermal relief) | --- ### ### Typical Application Circuit To ensure stability, the ADM7170 requires small ceramic capacitors. ```c // Recommended External Components for 4.2V Output: - Input Capacitor (Cin): 4.7 μF Ceramic (X5R or X7R) - Output Capacitor (Cout): 4.7 μF Ceramic (Low ESR) - SS Capacitor (Css): Optional (e.g., 1 nF to 10 nF for adjustable ramp) ```