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ADI LTC4151IS-2 1.2mA High Side Current And Power Monitors

Shenzhen Mingjiada Electronics Co., Ltd., as a leading distributor of electronic components in China, has been specialising in supplying the ADI LTC4151IS-2 high-side current and voltage monitor. This high-performance monitor plays a crucial role in telecommunications infrastructure, automotive electronics, industrial equipment, and consumer products, thanks to its wide operating voltage range of 7V to 80V and precise I2C interface data reporting capabilities.

Product Overview and Core Features

The LTC4151IS-2 is an advanced power monitor developed by ADI, specifically designed for precise measurement of high-side current, input voltage, and external voltage. The LTC4151IS-2 device is housed in a SOIC-16 package and operates within a temperature range of -40°C to 85°C, making it ideal for industrial and automotive applications. As a key product in ADI's power management product line supplied by Mingjiada Electronics, the LTC4151IS-2 holds a significant position in the power monitoring field due to its outstanding performance parameters and flexible interface design.

Wide voltage operating range: The LTC4151IS-2 supports an input voltage range of 7V to 80V, enabling it to easily handle the -48V power systems commonly found in telecommunications equipment and the high-voltage requirements of automotive electronics. The device's integrated high-voltage switches and level-shifting circuits ensure stable operation across the wide voltage range.

High-precision 12-bit ADC: The LTC4151IS-2's built-in 12-bit analogue-to-digital converter (ADC) continuously monitors high-side current, input voltage, and external voltage, providing precise digital measurement results. In default operating mode, the ADC continuously performs measurements, and when the host polls via the I2C interface, the device reports the latest measurement data.

Flexible measurement modes: In addition to continuous monitoring mode, the LTC4151IS-2 supports ‘snapshot’ mode, enabling single measurements on demand. This mode is particularly suitable for intermittent monitoring applications where power consumption needs to be minimised.

Separate I2C interface design: The LTC4151IS-2 device provides separate I2C data pins that can directly drive optocouplers, making it ideal for industrial control systems and power monitoring equipment requiring electrical isolation.

Technical details and operating principles

Current measurement is one of the core functions of the LTC4151IS-2. The device measures high-side current using an external sensing resistor. An integrated precision amplifier amplifies the voltage difference across the resistor and sends it to a 12-bit ADC for digitisation. This design maintains high measurement accuracy across a wide dynamic range (from milliamps to amperes) by simply selecting an appropriately valued sensing resistor. Notably, the LTC4151IS-2's current measurement is unaffected by power supply voltage fluctuations, thanks to its unique high-side measurement architecture.

Voltage Monitoring Function: In addition to current measurement, the LTC4151IS-2 can simultaneously monitor the input voltage and an external voltage. The input voltage is reduced to a range processable by the ADC via an internal resistor voltage divider network, while the external voltage is input via a dedicated pin. This multi-parameter synchronous monitoring capability enables the system to calculate power consumption (P=VI) in real time, providing comprehensive data for energy management.

I2C Communication Interface: The LTC4151IS-2 device communicates with the main controller via a standard I2C interface, supporting two rates: 100kHz and 400kHz. Its unique separated I2C pin design (SDAIN/SDAOUT) allows optocouplers or digital isolators to be inserted on the data lines, enabling electrical isolation—a critical feature in industrial control and power systems.

Alarm Function: The LTC4151IS-2 can be configured to trigger an alarm when current or voltage exceeds pre-set thresholds, notifying the main controller via a dedicated ALERT pin. This feature enables the system to quickly respond to abnormal conditions, enhancing reliability.

Low-power design is another highlight of the LTC4151IS-2. In normal operating mode, the device consumes only 1.2mA of static current; additionally, users can place the device in low-power standby mode via I2C commands, further reducing current consumption, making it suitable for battery-powered devices.

Typical Application Scenarios

1. Telecommunications Infrastructure

In -48V telecommunications power systems, the LTC4151IS-2 is an ideal current and voltage monitoring solution. Telecom equipment typically uses -48V as the standard supply voltage, and this negative voltage system requires high-side current monitoring to ensure stable operation. The LTC4151IS-2's 80V voltage rating easily meets telecom application requirements, and its isolated I2C interface facilitates electrical isolation between the power module and control unit, complying with telecom equipment safety standards.

2. Automotive Electronic Systems

Modern automotive electronic systems demand extremely high precision and reliability in power monitoring. The LTC4151IS-2's wide temperature range (-40°C to 85°C) makes it highly suitable for automotive applications, including monitoring:

In-vehicle infotainment system power

ADAS (Advanced Driver Assistance Systems) modules

Body control module power rails

Auxiliary monitoring in battery management systems (BMS)

3. Industrial Automation

In industrial control systems, the LTC4151IS-2 can be used for:

Current monitoring in motor drivers

Power management in PLC modules

Energy consumption analysis in industrial robots

Preventive maintenance monitoring in factory equipment

4. New Energy and Smart Grids

In photovoltaic inverters and energy storage systems, the LTC4151IS-2 can precisely monitor:

String current and voltage

DC-DC converter input/output parameters

System auxiliary power status

5. Consumer Electronics

In high-end audio equipment, high-power home appliances, and other applications, the LTC4151IS-2's precise power metering functionality is of significant value and can be used for:

Energy consumption monitoring and optimisation

Fault protection circuits

Battery level display in user interfaces