PCA9421BSZ - PMIC 2 Buck + 2 LDO for i.MX RT | NXP
MPN: PCA9421BSZ β Active| Qty | Unit Price | Extended |
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| 1 | $0 | $0.00 |
| 10 | $0 | $0.00 |
| 100 | $0 | $0.00 |
| 500 | $0 | $0.00 |
| 1,000 | $0 | $0.00 |
PCA9421BSZ Overview
A PMIC (power management integrated circuit) is a semiconductor device that consolidates multiple power conversion and regulation functions - such as buck converters, LDOs, battery chargers, and power sequencing logic - into a single package. In the power management hierarchy, the PMIC sits between the system power source (battery or adapter) and the load devices (MCU core, I/O, memory, analog rails), replacing several discrete regulators and reducing board area, BOM count, and design complexity.
The PCA9421BSZ integrates two high-efficiency buck converters and two low-noise LDOs with programmable output voltage ranges, enabling dynamic voltage scaling for low-power MCU cores. The device supports a 5 V input and is optimized for i.MX RT power domains, providing the core, I/O, and analog rails required by these processors. Its I2C-compatible control interface allows runtime voltage adjustment and power state management, which is essential for battery-powered systems that must balance performance against power consumption.
Typical applications include i.MX RT-based industrial controllers, portable medical devices, battery-powered IoT edge nodes, and handheld instrumentation. The integrated bucks deliver high efficiency at moderate load currents, while the LDOs supply noise-sensitive analog and I/O rails. The compact HVQFN-32 package with exposed pad supports thermal dissipation in space-constrained designs.
When designing with the PCA9421BSZ, pay close attention to inductor selection for the buck converters, input and output capacitor placement, and the thermal pad soldering to the PCB ground plane. The programmable output voltages must be configured through the I2C interface during initialization, so firmware sequencing must match the MCU power-up requirements.
This page synthesizes distributor pricing, drop-in alternatives, and practical design notes not found in the manufacturer datasheet, providing engineers with a single reference for selection, comparison, and layout decisions.
Drop-in alternatives for PCA9421BSZ β same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Variants in this series
Same-series models that are drop-in compatible with PCA9421BSZ (same form factor and footprint) β differing in Control Interface.
Quick Comparison Tool β Select alternative parts for side-by-side comparison:
PCA9420BS
β Drop-Inπ Reference alternative (not in catalog)
PCA9421BSZ Maximum Ratings & Electrical Characteristics
| Product Type | Power Management IC (PMIC) |
| Input Voltage | 5 V (adapter), Li-ion battery |
| Number of Buck Converters | 2 |
| Number of LDO Regulators | 2 |
| Output Voltage Range | Programmable |
| Target Processor | i.MX RT low-power MCU |
| Control Interface | I2C-compatible |
| Package | HVQFN-32 (5x5 mm) |
| Mounting Type | Surface Mount |
| Datasheet Revision | Rev. 1.0, 16 October 2023 |
PCA9421BSZ hvqfn-32 (5x5 mm) Pin Configuration Guide
Pin configuration for PCA9421BSZ (hvqfn-32 (5x5 mm) package). This power device features gate, drain, and source terminals. For non-polarized packages, refer to the manufacturer datasheet for exact pin 1 orientation and footprint details. Common applications include power supply design, motor driving, and load switching.
No detailed pinout data available for PCA9421BSZ.
Refer to the datasheet for full pin configuration.
Typical Applications
PCA9421BSZ is suitable for 6 applications: i.MX RT Crossover MCU Power Supply, Battery-Powered IoT Edge Nodes, Portable Medical Devices, Industrial Handheld Controllers, Wearable Electronics, Smart Home Sensor Hubs.
i.MX RT Crossover MCU Power Supply
The PCA9421BSZ is purpose-built to power i.MX RT crossover microcontrollers, supplying the core, I/O, and analog rails from a single integrated PMIC. Its two buck converters deliver high-efficiency core and system rails, while the two LDOs provide low-noise analog and I/O supplies required by the MCU's mixed-signal peripherals. The I2C-compatible interface allows firmware to adjust output voltages at runtime, enabling dynamic voltage scaling that matches the i.MX RT's operating modes. Using one PMIC instead of four discrete regulators reduces board area and simplifies power sequencing, which is critical because i.MX RT devices require specific rail power-up order. Designers should configure the programmable outputs to match the exact voltage domains of their specific i.MX RT variant before layout.
Recommended
Battery-Powered IoT Edge Nodes
In battery-powered IoT edge nodes, the PCA9421BSZ converts a Li-ion battery or 5 V adapter input into multiple regulated rails with high efficiency, extending operating time between charges. The two integrated buck converters handle the higher-current core and radio rails, while the LDOs supply low-noise sensor and analog front-end power. Because the outputs are I2C-programmable, the system can lower rail voltages during idle periods and raise them during active processing, directly reducing average power consumption. The compact 5x5 mm HVQFN-32 package fits space-constrained sensor nodes. A key trade-off is that the integrated bucks require careful inductor and capacitor selection to maintain efficiency at light load, which dominates IoT duty cycles.
Recommended
Portable Medical Devices
Portable medical devices such as handheld monitors and diagnostic instruments require clean, well-regulated power rails and compact form factors, both of which the PCA9421BSZ addresses. Its two LDOs provide low-noise supplies for sensitive analog measurement circuitry, while the buck converters efficiently power digital processing and display subsystems from a battery. The programmable output voltages allow the design to be tuned for different sensor and processor requirements without changing the power stage. Integrated sequencing simplifies compliance with the strict power-up order that medical processors demand. Designers must verify thermal performance in sealed enclosures, since the HVQFN-32 package relies on the exposed pad and PCB copper for heat dissipation.
Recommended
Industrial Handheld Controllers
Industrial handheld controllers and portable instrumentation benefit from the PCA9421BSZ's ability to generate multiple rails from a single battery or 5 V input. The two buck converters supply the processor and communication modules, while the LDOs power analog interfaces and reference circuits. The I2C-programmable outputs let the controller scale voltages based on operating mode, conserving battery in field use. The integrated PMIC reduces the component count compared with discrete regulator designs, improving reliability in rugged environments where fewer solder joints mean fewer failure points. Engineers should pay attention to input transient protection and decoupling, since industrial environments can present noisy supply rails that stress the PMIC's input stage.
Recommended
Wearable Electronics
Wearable electronics demand extremely compact power solutions with high efficiency at light load, making the PCA9421BSZ a strong candidate. Its 5x5 mm HVQFN-32 package integrates two bucks and two LDOs, replacing multiple discrete regulators and freeing board space for sensors and radios. The programmable outputs allow the wearable to operate in low-power states with reduced rail voltages, extending battery life. The LDOs supply clean power to biometric sensors and analog front ends, where supply noise directly affects measurement accuracy. A design consideration is that the buck converters' switching frequency and inductor choice must be optimized to avoid interference with sensitive RF or sensor circuitry in the tightly packed wearable form factor.
Recommended
Smart Home Sensor Hubs
Smart home sensor hubs aggregate multiple sensors and wireless radios, requiring several regulated rails with low standby power. The PCA9421BSZ provides two buck converters for the hub processor and radio power amplifiers plus two LDOs for sensor and analog rails, all from a 5 V adapter or battery backup. The I2C interface enables the hub firmware to manage power states dynamically, shutting down or reducing rails when sensors are idle. This integration reduces the BOM and simplifies the power tree compared with discrete regulators. Designers should ensure adequate input capacitance and thermal relief, since the hub may operate continuously and the PMIC's exposed pad must be soldered to a solid ground plane for heat dissipation.
Recommended
Recommended Products Summary
Engineering reference data for PCA9421BSZ β comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PCA9420BS |
|---|---|---|
| Package | HVQFN-32 (5x5 mm) | HVQFN-32 (same family) |
| Brand | NXP Semiconductors | NXP Semiconductors |
| Buck Converters | 2 | 2 |
| LDO Regulators | 2 | 2 |
| Input Voltage | 5 V adapter / Li-ion battery | 5 V adapter / Li-ion battery |
| Output Voltage | Programmable | Programmable |
| Control Interface | I2C-compatible | I2C-compatible |
| Target Application | i.MX RT low-power MCU | Low-power MCU / general PMIC |
Key Differentiators
- Integrated 2-buck + 2-LDO power tree (vs PCA9420BS)
- I2C-programmable output voltages (vs PCA9420BS)
- Compact 5x5 mm HVQFN-32 integration (vs PCA9420BS)
Design Notes
Select buck converter inductors according to the NXP PCA9421 datasheet recommended values to maintain efficiency and stable operation. Use low-DCR, shielded inductors to minimize EMI and resistive losses. Place input and output capacitors close to the PMIC pins to reduce loop inductance and output ripple. Estimated: at typical core rail currents, inductor DCR and switching losses dominate efficiency, so verify thermal rise under worst-case load.
The HVQFN-32 package relies on the exposed thermal pad for heat dissipation. Solder the pad to a solid ground plane with multiple thermal vias to spread heat. Estimated: with two bucks operating at moderate load, the package power dissipation can be significant; without adequate copper area the junction temperature may exceed the recommended limit. Follow the datasheet layout guidance for thermal pad dimensions and via placement.
Keep the buck converter switching loops (input capacitor, high-side/low-side switches, inductor) as small as possible to minimize radiated EMI. Route the I2C lines away from the switch nodes and keep them short with appropriate pull-up resistors. Place the LDO output capacitors close to their loads to preserve noise performance for analog rails.
Compliance Information
Compliance information was not present in the verified web data. Confirm RoHS, REACH, and AEC-Q100 status directly from the NXP product page or datasheet before design release.
