# CQ-1 Series Current Sensors Frequently Asked Questions

How much current can be flown in CQ-1 series?

It is possible for CQ-1 series to flow from -30A to 30A by DC sensed current.

How much pulse current can be flown in CQ-1 series?

It has been confirmed by an experiment in AKM labo that CQ-1 series did not break at a pulse current of 500A, 100us.

What is the difference of Maximum sensed current and Rated sensed current?

Maximum sensed current indicates the current value which can be applied for a long time in current sensor and depends on the cross-sectional area of the primary conductor. CQ-1 series can be damaged when they have been used for a long time over the maximum sensed current value. If current flows at  short period within msec, such as an over current, CQ-1 series is not damaged.

Rated sensed current is a current range where linear output of the current sensor is guaranteed. Output will be saturated when the current value exceeds the linear sensing range, and will return to normal output when the current value returns within the linear sensing range

What is the difference between the lineups of CQ-1 series?

Sensitivity, Rated sensed currentm, and Maximum sensed current are different.

Please use a product depending on a current range to measure or necessary current sensitivity.

What kind of packages does AKM use?

CQ-1 series use AKM's original package which is small and high reliability. (20mm x 8mm x 19mmt)

It is an advantage that the implementation area of the board is small.

How small is a current resolution?

CQ-121E is about 70mA, CQ-131E is about 180mA. (Do not use a low-path filter for the output;  in the case of response time 3μs）

Is it possible to sense both DC current and AC current?

They can sense both DC current and AC current.

What does "ratiometric" mean?

Ratiometric output means the output characteristic which varies in proportional to the power supply voltage. In the case that the output of a current sensor is captured by an A/D converter, ratiometric output can reduce the A/D conversion error due to variations of the reference voltage of A/D converter, by maiking reference voltage from the same power source as the current sensor. Both sensitivity and output voltage of AKM current sensors have the ratiometric characteristics. Recommended circuit is shown in Fig1.

 Fig.1　Recommended external circuits of CQ-1 series

What is the ESD tolerance?

CQ-1 series have the ESD tolerance which is more than 2000V by human body model and more than 200V by machine model.

Do CQ-1 series support the Pb-free product?

CQ-1 series are compliant with Pb-free.

What happens if a load current over more than +/-1mA is applied to CQ-1 series?

CQ-1 series do not output the correct value because output of CQ-1 series cannot drive the load.

Are CQ-1 series compliant with halogen-free/RoHS?

CQ-1 series are compliant with RoHS, but not compliant with halogen-free.