XC6210B332MR-G

The XC6210B332MR-G is a 700mA high-output-current low-dropout (LDO) voltage regulator from Torex Semiconductor. Part of the XC6210 series of CMOS LDO regulators, this device is specifically designed for applications requiring high current capability in a small package with minimal external components.

With a fixed output voltage of 3.3V (accurate to +-2%), the XC6210B332MR-G can deliver up to 700mA of output current from an input supply ranging from 2.0V to 6.0V. The dropout voltage is typically only 220mV at 500mA output current, making it highly efficient even in low-headroom applications such as post-regulating a 3.7V Li-ion battery down to 3.3V.

The device integrates a P-channel MOSFET as the pass element, which provides both low dropout voltage and low quiescent current (70uA typical in operation). In standby mode (CE pin low), the supply current drops to just 0.1uA, making the device ideal for battery-powered applications where power conservation is critical.

Key protection features include overcurrent protection with foldback current limiting (which reduces the short-circuit current to approximately 200mA to prevent overheating), inrush current suppression during power-up to prevent input voltage dips, and a discharge function that actively discharges the output capacitor when the device is disabled.

The XC6210 is designed to be stable with a small 1uF ceramic output capacitor, eliminating the need for larger electrolytic capacitors and saving board space. The SOT-25-5 package (a 5-pin variant of the popular SOT-23) is one of the smallest packages available for this current rating, enabling compact PCB designs. The -MR-G suffix denotes the SOT-25 package (MR) in the green/lead-free version (-G).

The XC6210B332MR-G is a CMOS-based low-dropout linear regulator that maintains a constant output voltage by adjusting the resistance of a P-channel MOSFET pass element. Here’s how it works:

1. Reference Voltage: A precision bandgap voltage reference generates a stable, temperature-compensated reference voltage of approximately 0.8V. This reference is the voltage standard against which the output is compared and is designed to have near-zero temperature coefficient.

2. Voltage Divider: An internal resistive voltage divider samples a fraction of the output voltage. For the 3.3V version, the divider ratio is approximately 0.24 (0.8V reference / 3.3V output). The accuracy of this resistor divider directly contributes to the +-2% overall output voltage accuracy.

3. Error Amplifier: A high-gain CMOS error amplifier compares the divided output voltage with the reference voltage. Any difference generates an error signal that drives the gate of the P-channel MOSFET pass transistor. The error amplifier also includes phase compensation to ensure stability across all load conditions.

4. P-Channel MOSFET Pass Element: The pass transistor is a P-channel MOSFET connected between VIN and VOUT. When the output voltage drops below setpoint, the error amplifier reduces the gate voltage (more negative relative to source), turning the MOSFET more fully on and increasing the output current. When the output rises above setpoint, the gate voltage increases, turning the MOSFET off more and reducing output current.

5. Current Limit Circuit: A current sense element monitors the output current. If the current exceeds the limit threshold (approximately 750mA typical), the current limit circuit takes control of the gate drive and limits the output current. The foldback characteristic further reduces the current when the output is shorted to ground (down to ~200mA), protecting both the regulator and the load from damage.

6. CE (Chip Enable): The CE pin controls the on/off state of the regulator. When CE is above the threshold (0.9V typ), the regulator is enabled. When CE is low, the regulator is shut down, reducing supply current to 0.1uA. The CE pin is compatible with both 3.3V and 5V logic levels.

7. Discharge Function: When the regulator is disabled (CE = low), an internal discharge switch connects the output to ground, actively discharging the output capacitor. This ensures the output voltage falls quickly when the regulator is turned off, which is useful in applications where the output must be fully discharged before re-enabling.

8. Soft-Start / Inrush Control: During startup, an internal soft-start circuit gradually ramps up the output voltage, limiting the inrush current that charges the output capacitor and preventing dips on the input supply line.

Package: SOT-25-5 (also known as SOT-25 or SOT-23-5). 5-pin small outline transistor package variant. Body dimensions: 2.9mm x 1.6mm x 1.1mm (typical height). 0.95mm pitch between leads. Surface-mount device. Tape and reel packaging (MR suffix).

• Battery-Powered Portable Devices: Power regulation for battery-operated equipment such as handheld meters, portable test instruments, GPS devices, and wearable electronics, where the combination of low quiescent current (70uA), ultra-low standby current (0.1uA), and low dropout voltage maximizes battery life across the discharge cycle.
• Wireless Communication Modules: Clean power supply for Wi-Fi, Bluetooth, Zigbee, and cellular modules, where the high ripple rejection (65dB @1kHz) and low output noise (90uVrms) provide the low-noise supply rail required for sensitive RF circuits to maintain optimal sensitivity and transmission performance.
• Microcontroller and Logic Power Supplies: 3.3V power supply for microcontrollers, FPGAs, CPLDs, memory chips, and other digital ICs in embedded systems, where the 700mA current rating provides sufficient headroom for typical MCU-based designs and the small SOT-25 package minimizes board space.
• Post-Regulation for Switching Power Supplies: Secondary LDO regulation following a switching DC-DC converter, where the XC6210 removes switching ripple and noise from the switcher output to provide clean analog or RF supply rails, leveraging its excellent ripple rejection performance to achieve very low output noise.
• Mobile and Wearable Electronics: Power supply for smartphones, smart watches, fitness trackers, and wireless earbuds, where the small SOT-25 footprint, low quiescent current, and CE pin for power gating enable efficient power management in space-constrained, battery-operated consumer devices.
• Digital Cameras and Portable Media: Multiple supply rails in digital cameras, portable media players, and handheld gaming devices, providing regulated power for image sensors, audio codecs, display drivers, and memory circuits, with the inrush suppression feature ensuring clean power-up sequencing.
• Reference Voltage Sources: Providing stable, low-noise reference voltages for ADCs, DACs, sensor signal conditioning, and precision analog circuits, where the low output noise and high line rejection ensure that reference voltage variations do not degrade measurement accuracy.
• Consumer Electronics and Home Appliances: Power regulation in set-top boxes, smart home devices, small appliances, and LED drivers, where the low cost, small package, and minimal external components (just two capacitors) make it ideal for high-volume, cost-sensitive consumer applications.