Overview
The LM26484SQE/NOPB is a multi-function, configurable Power Management Unit (PMU) produced by Texas Instruments. This device integrates two highly efficient 2.0A step-down DC/DC converters, one Low-Dropout (LDO) controller, a Power On Reset (POR) circuit, and thermal overload protection circuitry. The LM26484 is designed to provide flexible power sequencing and management for various applications, including digital cores, automotive infotainment, set-top boxes, and networking routers.
Key Specifications
| Parameter | Conditions | Min | Typ | Max | Units |
|---|---|---|---|---|---|
| VIN Range | AVDD=VIN1=VIN2 | 3.0 | 3.3 | 5.5 | V |
| Feedback Voltage Accuracy | -1.0 | 0.5 | +1.0 | % | |
| DC Line Regulation | 3.0 < VIN < 3.6, IO =1000 mA | 0.174 | %/V | ||
| DC Load Regulation | 100 mA < IO < IMAX | 0.75 | %/A | ||
| Oscillator Frequency | 1.8 | 2.0 | MHz | ||
| Peak Switching Current Limit | 3.2 | A |
Key Features
- Two 2.0A step-down DC/DC converters (Buck1 and Buck2) with 180° phase shift between their clocks.
- Externally adjustable output voltages for Buck1 and Buck2: 0.8V–3.5V.
- 2 MHz PWM switching frequency.
- ±1% feedback voltage accuracy.
- Automatic soft start and current overload protection.
- PWM/PFM efficiency modes available.
- LDO controller with externally adjustable output voltage.
- Thermal overload protection and power-on reset (POR) circuit.
- Low dropout operation with 100% duty cycle capability.
- Internal synchronous rectification for improved efficiency.
Applications
- Digital cores and I/Os (FPGAs, ASICs, DSPs).
- Automotive infotainment systems.
- Set-top boxes.
- Cordless phone base stations.
- Networking routers.
- Printers.
Q & A
- What is the input voltage range of the LM26484?
The input voltage range is from 3.0V to 5.5V.
- What is the maximum output current of each buck converter?
Each buck converter can deliver up to 2A of output current.
- What is the switching frequency of the buck converters?
The switching frequency is 2 MHz.
- Does the LM26484 have built-in thermal protection?
- How are the output voltages of the buck converters adjusted?
The output voltages are externally adjustable using feedback resistors.
- What is the purpose of the LDO controller in the LM26484?
The LDO controller is a linear regulator designed for low noise analog loads.
- Can the LM26484 operate in low dropout mode?
- What is the function of the power-on reset (POR) circuit?
The POR circuit provides an active low reset output during power-on.
- How does the soft-start feature work in the LM26484?
The soft-start feature gradually ramps up the output voltage over about 500 µs to reduce start-up stresses and surges.
- What are the key considerations for selecting an NFET for the LM26484?
The NFET should have a maximum power rating larger than the application requires, and ensure the VGS is ≥1.5V.
