ACM34063
3A synchronous buck converter with 4.5V-36V input, adjustable output, and 94% peak efficiency for industrial apps.
Product Overview
Description
The ACM34063 is a high-efficiency synchronous step-down DC-DC converter capable of delivering up to 3A continuous output current.
With a wide input voltage range of 4.5V to 36V and adjustable output voltage down to 0.8V, this converter is ideal for industrial and automotive applications.
The synchronous rectification architecture achieves peak efficiency of 94%, reducing power loss and thermal requirements compared to non-synchronous solutions.
Product Series
ACM
Primary Application
Industrial power supplies
Key Features
- Wide input voltage range: 4.5V to 36V
- High efficiency: up to 94%
- 3A continuous output current
- Adjustable switching frequency
- Internal compensation
- Soft-start function
- Overcurrent protection
- Thermal shutdown protection
Specifications
| Input Voltage | 4.5V to 36V |
|---|---|
| Output Voltage | 0.8V to 24V (adjustable) |
| Output Current | 3A continuous |
| Peak Efficiency | 94% |
| Switching Frequency | 300kHz to 2.4MHz (adjustable) |
| Quiescent Current | 0.5mA |
| Shutdown Current | 2μA |
| Load Regulation | ±0.5% |
| Line Regulation | ±0.3% |
| Temperature Range | -40°C to +125°C |
| Package | TSSOP-16 |
Applications
Industrial power supplies
Industrial automation and control
Automotive electronics
Automotive and EV electronics
Battery chargers
Battery and charging management
LED drivers
Motor drive and control systems
Distributed power systems
Electronic system design
FAE Expert Insights
"In my 18 years of power supply design, I've found the ACM34063 to be an excellent general-purpose buck converter for industrial applications. The wide 4.5V-36V input range covers most industrial and automotive scenarios, and the 94% peak efficiency is impressive for a converter in this price range. I particularly appreciate the adjustable switching frequency - being able to optimize for efficiency or size depending on the application is valuable. The internal compensation simplifies design and reduces component count. One important recommendation: pay close attention to the input capacitor selection. Use low-ESR ceramic capacitors (X5R or X7R) with adequate voltage rating. I've seen systems with insufficient input capacitance exhibit instability under load transients. For the inductor, I recommend shielded types to minimize EMI. The thermal performance is good with θja of 40°C/W, but for 3A operation at high ambient temperatures, consider adding copper area or a small heatsink. Overall, this is a reliable, cost-effective buck converter that I frequently recommend for industrial power supplies."
Excellent efficiency and wide input range make it ideal for industrial power applications
— David Park, BeiLuo
Frequently Asked Questions
What is the maximum output current of the ACM34063?
The ACM34063 can deliver up to 3A continuous output current with proper thermal management. The actual maximum current depends on input voltage, output voltage, ambient temperature, and heatsinking. At high input-output voltage differentials, thermal limitations may reduce the maximum current. For example, with Vin = 24V, Vout = 5V, and Ta = 85°C, the maximum current may be limited to 2A due to power dissipation. Always verify thermal performance in your specific application using the thermal resistance specifications (θja = 40°C/W for TSSOP-16).
Design for 3A with adequate heatsinking. Perform thermal calculations for your operating conditions.
How do I set the output voltage?
The output voltage is set using a resistor divider from Vout to FB (feedback) pin to ground. The formula is Vout = 0.8V × (1 + R1/R2), where R1 is the top resistor (Vout to FB) and R2 is the bottom resistor (FB to GND). For example, for 5V output: R1 = 52.5kΩ, R2 = 10kΩ. Use 1% tolerance resistors for accurate output voltage. Place the resistors close to the FB pin to minimize noise pickup. The feedback pin has 0.8V reference voltage with 1% accuracy. For adjustable versions, output voltage can be set from 0.8V to 24V.
Use resistor divider formula Vout = 0.8V × (1 + R1/R2). Place resistors close to FB pin.
What switching frequency should I use?
Switching frequency selection involves trade-offs between efficiency, component size, and EMI. Lower frequencies (300-500kHz) provide higher efficiency but require larger inductors and capacitors. Higher frequencies (1-2MHz) allow smaller passive components but have lower efficiency due to increased switching losses. The ACM34063 supports 300kHz to 2.4MHz. For maximum efficiency, use 300-500kHz. For minimum size, use 1.5-2MHz. For automotive applications, consider fixed frequency operation below 2MHz to avoid AM radio interference. The frequency can be set with an external resistor or synchronized to an external clock.
Use 300-500kHz for efficiency, 1.5-2MHz for small size. Avoid AM band for automotive.
How do I minimize EMI from the switching regulator?
Minimizing EMI requires attention to layout, filtering, and shielding. Keep the high-current switching loop (input cap, switch node, inductor) as small as possible. Place input capacitor close to Vin and GND pins. Use shielded inductors to contain magnetic fields. Add an RC snubber (10Ω + 100pF) across the switching node if needed. Implement a pi filter on the input for conducted EMI. Use a solid ground plane under the converter. Keep sensitive analog circuits away from the switching node. Follow the recommended PCB layout in the datasheet. For radiated EMI, ensure good ground continuity and minimize trace lengths.
Keep switching loops small, use shielded inductors, add input filtering, follow reference layout.
Can the ACM34063 be used for negative output voltages?
Yes, the ACM34063 can be configured as an inverting buck-boost converter to generate negative output voltages. In this configuration, the output is negative with respect to ground, and the IC ground pin is connected to the negative output. The maximum output current is reduced compared to buck configuration due to higher switch currents. For example, a -5V output at 1A from 12V input is achievable. Refer to the datasheet for the inverting configuration schematic. Note that the input voltage rating is reduced in inverting mode because the switch sees Vin + |Vout|. For high current negative outputs, consider using a dedicated inverting converter.
Use inverting buck-boost configuration for negative outputs. Reduce current rating by 30-40%.
What protection features does the ACM34063 include?
The ACM34063 includes comprehensive protection features: Overcurrent protection (OCP) limits peak switch current to 4.5A typical. Thermal shutdown disables the converter when die temperature exceeds 160°C, with 20°C hysteresis. Under-voltage lockout (UVLO) prevents operation when input voltage is below 4.0V. Soft-start limits inrush current during startup with 4ms ramp time. These protection features ensure reliable operation under fault conditions and prevent damage to the converter and load. The protection features are automatic and require no external components.
Protection features are automatic. Ensure proper heatsinking to avoid thermal shutdown.