Cyntec MUN12AD03-SH vs MUN12AD03-SEC: Key Differences & Replacement Guide

The Cyntec MUN12AD03-SH and MUN12AD03-SEC are compact, non-isolated 3A point-of-load (POL) DC-DC power modules designed for embedded electronics, industrial systems and distributed power applications.

Both modules integrate a high-frequency switching regulator and power inductor in a compact surface-mount package. They support adjustable output voltage, automatic power-saving operation, soft-start control and protection functions.

However, they are not pin-to-pin interchangeable. Key differences include input voltage range, output voltage range, package dimensions, feedback reference voltage and PCB pin assignments.

This guide compares the MUN12AD03-SH and MUN12AD03-SEC using manufacturer specifications, helping engineers select the appropriate module and evaluate replacement requirements.

1. MUN12AD03-SH vs MUN12AD03-SEC: Specifications Comparison

The following specifications are based on official Cyntec datasheets.

Key takeaway: Both devices deliver up to 3A, but the SEC version offers a smaller footprint and a slightly wider input voltage range. The SH version supports lower output voltages down to 0.6V.

2. Input Voltage Differences: 16V vs 17V

The MUN12AD03-SH supports an input voltage range of 4.5V to 16V, while the MUN12AD03-SEC operates from 4.5V to 17V.

Both are suitable for nominal 12V input systems, provided the actual operating conditions remain within the manufacturer's ratings.

When Does the Extra 1V Matter?

For designs using a regulated 12V supply, both modules may satisfy the input voltage requirement.

However, if the input supply can exceed 16V during normal operation, the SEC version provides additional operating voltage headroom.

This does not mean that the SEC module is automatically protected against high-energy transients or automotive load-dump events. External transient protection may still be necessary.

3. Output Voltage Differences: 0.6V vs 0.8V Minimum

One of the most important electrical differences is the adjustable output voltage range.

• MUN12AD03-SH: 0.6V to 5.0V

• MUN12AD03-SEC: 0.8V to 5.5V

Low-Voltage Core Power

If an FPGA, ASIC or processor requires a 0.6V or 0.75V power rail, the SH module may be suitable, but the SEC module cannot be used within its specified output voltage range for those rails.

For common 1.0V, 1.2V, 1.8V and 3.3V power rails, both modules support the required nominal output voltage, subject to input-voltage limitations and thermal design.

5V Output Applications

Both modules support an adjustable 5V output under appropriate operating conditions.

The SEC version additionally supports output voltages up to 5.5V, while the SH version is limited to 5.0V.

Engineers should also verify the input-to-output voltage relationship, maximum duty cycle and the recommended operating conditions for the selected output voltage.

4. Package Dimensions and PCB Footprint

The package is another major difference between these two Cyntec power modules.

MUN12AD03-SH Package

• Package: QFN

• Dimensions: 3.5 × 3.5 × 1.7mm

• Surface-mount construction

• Integrated switching regulator and inductor

MUN12AD03-SEC Package

• Package: DFN

• Dimensions: 3.0 × 2.8 × 1.5mm

• Surface-mount construction

• Integrated switching regulator and inductor

The SEC package occupies approximately 8.4mm² of nominal footprint area, compared with approximately 12.25mm² for the SH package.

This represents about a 31% reduction in nominal package footprint area.

However, the actual PCB area required depends on recommended land patterns, external capacitors, feedback components and routing clearances.

Important: The SH and SEC packages have different pin assignments and land patterns. The modules cannot be directly exchanged on an existing PCB without redesign.

5. MUN12AD03-SH vs SEC Pinout Differences

Although both modules provide VIN, VOUT, GND, EN, FB, PGOOD and SS functions, their pin numbers and physical layouts differ.

The manufacturer's package drawings must be used to identify the exact pad geometry and pin orientation.

The difference in pin assignments confirms that MUN12AD03-SH and MUN12AD03-SEC are not drop-in replacement components.

6. Feedback Voltage and Output Resistor Differences

Both devices use external feedback resistors to program the output voltage, but they have different feedback reference voltages.

• MUN12AD03-SH: 0.6V nominal feedback reference.

• MUN12AD03-SEC: 0.8V nominal feedback reference.

The basic output-voltage relationship is:

VOUT = VREF × (1 + RFB_T / RFB_B)

Where RFB_T connects VOUT to FB and RFB_B connects FB to ground.

Example: 1.8V Output

For a 1.8V output, the required resistor ratio is different.

MUN12AD03-SH:

RFB_T / RFB_B = 1.8 / 0.6 - 1 = 2

MUN12AD03-SEC:

RFB_T / RFB_B = 1.8 / 0.8 - 1 = 1.25

This means that even when both modules generate the same nominal 1.8V output, the feedback resistor network cannot automatically be reused.

Always follow the recommended resistor values and output-voltage programming instructions in the corresponding Cyntec datasheet.

7. Efficiency and Thermal Performance

Both modules specify peak efficiency of approximately 91% at 12V input.

However, this does not mean that their efficiency is identical under every operating condition.

Actual conversion efficiency depends on:

• Input voltage

• Output voltage

• Output current

• Switching and conduction losses

• PCB layout and thermal environment

Thermal Design Considerations

The SH and SEC modules have different package sizes and thermal characterization conditions.

The SEC datasheet specifies an ambient operating range up to +125°C with derating considerations, while the SH datasheet specifies an ambient operating range up to +85°C.

These values should not be interpreted as guaranteed full-load operating temperatures.

Engineers should review the manufacturer-provided thermal derating curves and verify the module temperature under actual operating conditions.

The SEC package is smaller, but a smaller package does not automatically result in better or worse thermal performance.

8. Can MUN12AD03-SEC Replace MUN12AD03-SH?

Short answer: Not as a direct drop-in replacement.

The SEC may be considered as an electrical alternative in a redesigned circuit, but several differences must be evaluated.

When Is the SEC a Reasonable Alternative?

The MUN12AD03-SEC may be considered when:

• The required output current is within 3A.

• The output voltage is within 0.8V to 5.5V.

• The input supply remains within 4.5V to 17V.

• The PCB can be redesigned for the SEC package.

• The feedback components and capacitor network can be updated.

• Thermal and transient performance can be validated.

For designs requiring a 0.6V output, the MUN12AD03-SH may remain the more appropriate choice because the SEC has a minimum specified output voltage of 0.8V.

9. Which Module Should You Choose?

Choose MUN12AD03-SH When:

• The power rail requires an output as low as 0.6V.

• The existing PCB is designed for the SH package.

• The input supply remains within 4.5V to 16V.

• The operating temperature and thermal requirements match its datasheet.

Choose MUN12AD03-SEC When:

• A smaller package footprint is beneficial.

• The output voltage requirement is between 0.8V and 5.5V.

• An input voltage up to 17V is required.

• The design can accommodate the SEC footprint and pin configuration.

• The manufacturer's thermal derating conditions are satisfied.

For a new PCB design, the SEC may provide space-saving advantages. For an existing SH-based design, changing to SEC requires engineering verification and PCB modifications.

10. Typical Applications

Both Cyntec modules are suitable for selected point-of-load DC-DC conversion applications.

Industrial Embedded Systems

Industrial computers and embedded control boards often require compact 12V-to-low-voltage conversion for digital circuits, processors and supporting peripherals.

Networking Equipment

Routers, access points and communications equipment may use non-isolated POL modules to generate local low-voltage rails.

FPGA and Digital Logic Power

Depending on output voltage and transient load requirements, a 3A uPOL module can support selected FPGA auxiliary rails and low-current digital power domains.

LDO Replacement

Where system requirements permit, a switching POL module may be evaluated as a higher-efficiency alternative to linear voltage regulation.

Noise, ripple, thermal and transient requirements must be evaluated before replacing an LDO in sensitive circuits.

11. Frequently Asked Questions

Q1: Are MUN12AD03-SH and MUN12AD03-SEC pin-compatible?

No. They use different package dimensions and pin assignments. A PCB redesign is required when replacing one with the other.

Q2: Can both modules deliver 3A output current?

Yes. Both are rated for up to 3A output current, subject to operating voltage, cooling and thermal derating requirements.

Q3: Which Cyntec module is smaller?

The MUN12AD03-SEC is smaller, measuring 3.0 × 2.8 × 1.5mm, compared with 3.5 × 3.5 × 1.7mm for the MUN12AD03-SH.

Q4: Can MUN12AD03-SEC replace SH in a 1.8V power rail?

Both devices support a nominal 1.8V output. However, the package, pinout and feedback reference differ. Replacement requires PCB changes, recalculation of the feedback network and validation of the complete power circuit.

12. Cyntec MUN12AD03-SH and SEC Datasheets

For complete electrical characteristics, package drawings, recommended PCB footprints and performance curves, refer to the official manufacturer documentation.

• Cyntec MUN12AD03-SH Datasheet – Rev.06 (PDF)

• Cyntec MUN12AD03-SEC Datasheet – Rev.00 (PDF)

Always confirm the latest datasheet revision before finalizing component selection or production replacement.

13. MUN12AD03-SH and MUN12AD03-SEC Price, Stock & RFQ

Are you sourcing Cyntec MUN12AD03-SH or MUN12AD03-SEC for a new PCB design, production requirement or replacement project?

DataStorageIC can assist with pricing, availability inquiries and sourcing requirements for Cyntec DC-DC power modules.

Please provide:

• Required manufacturer part number

• Quantity and estimated annual demand

• Target price, if available

• Required delivery date

• Destination country or region

• Required technical documentation

• Existing part number if a replacement is needed

For replacement inquiries, include the existing PCB footprint, input voltage, output voltage and load current requirements so that compatibility can be evaluated.

Request Pricing and Availability: Visit DataStorageIC to submit your Cyntec part-number requirements through the website inquiry form.

Pricing, available quantity and lead time are subject to confirmation.

14. Related Cyntec Power Modules

For additional Cyntec point-of-load DC-DC converters and higher-current power modules, explore the following resources:

• Cyntec POL Power Modules and DC-DC Converters – Browse MUN, MSN and related Cyntec power module models.

• Cyntec 12V POL Modules: 3A vs 5A vs 12A vs 20A – Compare representative module current ratings and output requirements.

• Cyntec POL Power Modules Selection Guide – Explore broader point-of-load power module selection considerations.

Conclusion

The Cyntec MUN12AD03-SH and MUN12AD03-SEC are both compact 3A non-isolated DC-DC power modules, but they differ in several important design characteristics.

The SH supports output voltages as low as 0.6V, while the SEC offers a smaller package, a maximum input voltage of 17V and an adjustable output range extending to 5.5V.

Despite their similar current ratings, the two modules have different footprints, pin assignments and feedback reference voltages. They should not be treated as direct drop-in replacements.

For Cyntec MUN12AD03-SH or MUN12AD03-SEC datasheets, quotation requests or replacement sourcing assistance, contact DataStorageIC with your electrical and mechanical requirements.