# Need a buck converter with below specifications of intrinsic safety

Specifications:
Input Voltage range : 1.8,2,3.3V- 30V
Output Voltage:3.3V
Temperature range: –55°C to 85°C or above
Output current: above 6mA
Switching Frequency: Should be greater than 100KHZ
Ripple frequency: In the range of 100KHZ
Buck converter with intrinsic safety feature is required(Lower value inductor(Max 10uH) and Lower value capacitor(20uF-sum of CIN and COUT)

Hello,

Do you need a converter for each of those inputs or one converter that can take in 1.8-30V?

Best Regards,
Yu

Yes, I need a DC-DC converter which works in 4-20mA input signal that is, 2-30V input voltage range

Just want to confirm, you are looking for a buck-boost to output 3.3V with the wide input range?

Best Regards,
Yu

Actually, Not a buck boost I need a buck powered by a 4-20mA current source.
Specifications:
Input Voltage range: 1.8,2,3.3V- 30V
Output Voltage:3.3V
Temperature range: –55°C to 85°C or above
Output current: above 6mA
Switching Frequency: Should be greater than 100KHZ
Ripple frequency: In the range of 100KHZ
Buck converter with intrinsic safety feature is required(Lower value inductor(Max 10uH) and Lower value capacitor(20uF-sum of CIN and COUT)

It sort of looks impossible. How does a buck converter with 1.8Vin make 3.3V?
If the minimum input current is 4mA and the output current is 6mA even a 100% efficient converter would need a Vin of about 5V.

It sounds like you are trying to power something at the end of an industrial 4-20mA current loop.

At least, 3V minimum required in the input voltage range.
Yes you are right it is a loop powered board with 4-20mA current supply.
I need a device with these specification and temperature range(-55 Degree Celsius Minimum)
Kindly share the suitable component as soon as possible

A buck converter won’t be able to make 3.3V from 3V

It looks like your “application” requires 6mA to work. It looks like the compliance voltage on the 4-20mA loop is 24V. At the end of a long line the sensor will see the voltage drop in the lines feeding it. If we have a low drop out regulator we can drop 20.7V in the line before we run into trouble. So Vin to the sensor will be 3.3V. If we decide that is has to work to 1.8V ( it won’t) This means we can tolerate.22.2V of drop n the lines. This would be a 7% longer wire the previous case. In fact if you required the circuit to work at zero volts in (by some magic) the lines feeding it would only be 15% longer than the reasonable case ( a low drop out buck converter) This limitation could be fixed by going up a wire size in order to get less drop.

The worst case drop will be when the output signal is 20mA so from that point of view a 6mA circuit load will not be a problem the circuit will also have to drive an extra 14mA in order to hit 20mA.

Kindly share the suitable component

A buck with a 2V input will not be able to give a 3.3V output.
For an input that will go below 3.3V, a buck-boost will be a more suitable option.
MP4245 | 36V, 6A Peak, Buck-Boost Converter with I2C Interface for Power Delivery | MPS (monolithicpower.com)

If the input will not go below 3.3V, here are a few buck options. Modules are fully integrated and generally offer small solution size, minimum components, better EMI, and fast time to market.
MPM3506A

MPM3515 | 1.5A, 36V, Synchronous Step-Down Power Module with Integrated Inductor and Power Good | MPS (monolithicpower.com)

Regarding the temperature range, is there a reason why it needs to go down to -55deg C? Our devices typically go down to -40degC for recommended operating range. This is listed on the datasheet and you can also find the reliability reports for the devices on the website under the Support section.

Hope this helps.

Best Regards,
Yu

4-20mA loops are an old timey industrial control system. So this could be powering some sensor sitting outside in Alaska hundreds of yards from the control room. Measuring critical parameters in an oil refinery. -55 isn’t crazy.