CH707
Preliminary - Revised Aug 2021
Page 1 of 76
CH707
Automotive-Grade, Isolated Current Sensor IC with Common-Mode
Field Rejection and Over-Current Detection
This is advanced information on a new product now in development or undergoing evaluation. Details are subject to change without notice and Cosemitech
assumes no obligation for future manufacture of this product. Contact Cosemitech for the latest status.
Key Features
Package
• AEC-Q100 automotive qualified
• Differential Hall sensing rejects common-mode fields
• Reinforced isolation: V
ISO
4800V
RMS
, V
WVRI
605V
RMS
• Single supply: 3.3V or 5V
• Output voltage proportional to AC or DC current
• Low primary conductor resistance: 0.85 mΩ
• Minimized total sensitivity error: ±0.7%
• Wide-bandwidth: 450kHz
• Fast response: 1.2µs
• Over-current detection
• Integrated shield virtually eliminates capacitive coupling from
current conductor to die
• User-selectable ratiometric behavior of sensitivity, quiescent
voltage, and clamps for simple interface with ADC
• Integrated digital temperature compensation circuitry
• Reference pin can facilitate the follow up design
• 48 bits ID Number option
• Functional-safety ASIL-B capable: CH707*F
SOIC-16
Applications
• Motor control
• Load detection and
management
• Switch-mode power
supplies
• Over current protection
• Public speaker current
sensing
Functional Block Diagram
CH707
Preliminary - Revised Aug 2021
Page 2 of 76
Description
The CH707 current sensor IC is an economical and precise solution for AC or DC current sensing
in industrial, automotive, commercial, and communications systems. The small package is ideal
for space-constrained applications while also saving costs due to reduced board area. Typical
applications include motor control, load detection and management, switched-mode power
supplies, and overcurrent fault protection.
The device consists of a precise, low-offset, linear Hall sensor circuit with a copper conduction
path located near the surface of the die. Applied current flowing through this copper conduction
path generates a magnetic field which is sensed by the integrated Hall IC and converted into a
proportional voltage. The internal resistance of this conductive path is 0.85 mΩ typical, providing
low power loss.
The terminals of the conductive path are electrically isolated from the sensor leads. This allows
the CH707 current sensor IC to be used in high-side current sense applications without the use of
high-side differential amplifiers or other costly isolation techniques.
The CH707 is a factory programmable, low noise high accuracy linear Hall effect-based sensor IC
at the full 450KHz bandwidth.
These Hall effect sensor ICs provide a voltage output that is proportional to the applied magnetic
field. The quiescent voltage output is user adjustable; the value can be programmable with six
different situations: around 50% of the supply voltage or 10% of the supply voltage, or set at
constant value of 2.5V, 0.5V, 1.65V, 0.33V.
The accuracy of the device is enhanced via programmability on the VREF pin for end of-line
optimization without the added complexity and cost of a fully programmable device. The device
using EERPOM to optimize device sensitivity and the quiescent output voltage (QVO) (output
with no magnetic field) for a given application or circuit. The CH707 also allow for optimized
performance over temperature through programming the temperature coefficient for both
Sensitivity and QVO at end of line test. User selectable output voltage clamp, Broken ground wire
detection and the programmable nature of the CH707 enables it to account for manufacturing
tolerances for high reliability in automotive applications over a wide temperature range, –40°C to
150°C.
CH707 provides another VREF output. This Pin is an IO pin. Normally the output voltage is equal
to the quiescent voltage of output at zero magnetic field input. It can also receive the signal from
external reference voltage.
The lead-frame is plated with 100% matte tin, which is compatible with standard lead (Pb) free
printed circuit board assembly processes. Internally, the device is Pb-free, except for flip-chip
high-temperature Pb-based solder balls, currently exempt from RoHS. The device is fully
calibrated prior to shipment from the factory.