POWER AND LINEAR IC SOLUTIONS

Dual High Side Current Sense Amplifier Suits Wide Range of Applications

Linear Technology’s LTC6103 is a versatile, high-voltage dual current sense amplifier. It contains two independent, high side current sense amplifiers with exceptional precision and fast response capability.

The LTC6103’s amplifiers operate with a maximum input voltage up to 70V, a valuable feature when power supply failures or sudden load changes can lead to high voltage conditions. With a step response time from 0V to 2.5V of under 1µs, the device can be used for detection functions in automating power shutdown under fault conditions.

The dual-amplifier topology is suitable for multiple current sensing applications such as battery charge and H-bridge driver circuits. In the latter case, dual channel operation allows monitoring of both high sides within the bridge, eliminating large common mode voltage variation as the voltage transitions from one leg to another.

In addition, the second amplifier can be used for bi-directional operation or high voltage level translation. The operating range of 4V to 60V was designed to cover a broad spectrum of applications since many automotive and industrial applications must withstand large voltage transients. Using two amplifiers with different shunt resistor values in series allows further application flexibility: the monitoring of very small currents with one amplifier and very high current failure modes with the second amplifier.



The ability to operate with a differential input voltage of up to 66V means that the device can also be used as a high voltage translator. The supply pin of each amplifier is connected to its respective load-side input, so that its current draw is included in the current measurement. This also means that the part can operate with a differential sense voltage up to the full high voltage level.

Gain for each amplifier is set by two resistors: since these are the primary determinants of accuracy, using precision resistors allows for accuracy better than 1%. The LTC6103 has a low input bias current of much less than 1µA (typically 100nA), practically eliminating input current as a source of error for most applications. The minimum measurable current is set by the base current, so that the LTC6103 can measure currents down to 1µA.

Precision measurement is also facilitated by the component’s low input offset voltage of just 450µV (maximum, over temperature and voltage).

Supplied in an MS8 (8-lead plastic Mini Small Outline) Package, the LTC6103 offers space savings and simpler board layout than the alternative approach of using two single channel SOT23 devices.

Features

• Two independent current sense amplifiers in a single Mini Small Outline Package (MSOP)
• Wide supply range: 4V to 60V, 70V absolute maximum
• Low offset voltage: 450µV maximum
• Fast response time: 1µs
• Gain configurable with external resistors
• Low input bias current: 170nA maximum
• PSRR: 110dB minimum (6V to 60V)
• Output current: 1mA maximum
• Low supply current: 275µA per amplifier @ 12V supply
• Specified for –40°C to +125°C temperature range

Applications

• Current shunt measurement
• Battery monitoring
• Remote sensing
• Power management
• H-Bridge load monitoring
• Bi-directional current sensing
• High/low gain ranging
• Level translation

For further information, including a copy of the 'Two Current Sense Amps Solve Single Amps Limitations' article, please click here