Key Specs
| Spec | Value | Condition | Source |
|---|---|---|---|
| Clock Sync | No | Digi-Key | |
| Control Features | Frequency Control | Digi-Key | |
| Duty Cycle (Max) | 96% | Digi-Key | |
| Function | Step-Up, Step-Down, Step-Up/Step-Down | Digi-Key | |
| Mounting Type | Surface Mount | Digi-Key | |
| Number Of Outputs | 1 | Digi-Key | |
| Operating Temperature Range | -40°C ~ 85°C (TA) | Digi-Key | |
| Output Configuration | Positive, Isolation Capable | Digi-Key | |
| Output Phases | 1 | Digi-Key | |
| Output Type | Transistor Driver | Digi-Key | |
| Package Case | 8-SOIC (0.154”, 3.90mm Width) | Digi-Key | |
| Serial Interfaces | - | Digi-Key | |
| Supplier Device Package | 8-SOIC | Digi-Key | |
| Supply Voltage (Typ) | 7.6V ~ 20V | Digi-Key | |
| Switching Frequency (Typ) | 500kHz | Digi-Key | |
| Synchronous Rectifier | Yes | Digi-Key | |
| Topology | Buck, Boost, Flyback, Forward Converter | Digi-Key |
When To Use
Use the MIC38C43ABM in applications requiring a single output transistor driver with synchronous rectification, such as isolated or non-isolated step-up, step-down, or step-up/step-down power supplies. Its frequency control capability and typical switching frequency of 500kHz make it suitable for compact, surface-mount designs operating within a 7.6V to 20V supply voltage range. Ideal applications include DC/DC converters in industrial and automotive systems operating within -40°C to 85°C ambient temperature, where a maximum duty cycle of 96% is needed to optimize power transfer.
When Not To Use
Do not use the MIC38C43ABM in multi-output power supplies or applications requiring integrated serial interfaces, as it supports only a single output and has no serial communication capability. Avoid using this device in high-frequency applications exceeding 500kHz switching frequency or where synchronous rectification is not required. For such cases, consider dedicated multi-phase controllers or devices with integrated digital interfaces and higher frequency ratings.
Application Notes
The switching node connected to the external MOSFET gate must have the smallest possible loop area to minimize EMI and switching losses. The feedback pin is noise-sensitive and should be routed away from high-current switching nodes to ensure stable regulation. Due to the synchronous rectification feature, a heatsink is typically not required at normal operating points within the specified ambient temperature range (-40°C to 85°C), but thermal considerations should be assessed based on power dissipation in the external MOSFET and inductor.
Gotchas
-
Incorrect Inductor Selection:
If the engineer selects an inductor with a saturation current below the maximum load current, the inductor will saturate during operation, causing excessive ripple, increased losses, and potential device shutdown.
Fix: Choose an inductor rated above the maximum load current and compatible with the 500kHz switching frequency. -
Improper Layout of Switching Node:
Routing the gate drive and switching node traces with large loop areas can lead to excessive EMI and voltage spikes, causing erratic operation or device damage.
Fix: Minimize the loop area of the gate drive circuit and keep high-current paths short and well-grounded. -
Ignoring Feedback Pin Noise Sensitivity:
Placing the feedback trace near the switching node can introduce noise into the feedback loop, resulting in unstable output voltage or oscillations.
Fix: Route the feedback trace away from noisy switching nodes and use proper filtering techniques.