Linear Technology Corp. introduced the LTC4151, a high side power monitor that measures current and input voltages from 7 to 80V. The LTC4151 utilizes an internal 12-bit ADC to continuously measure both high side current and input voltage to give a true power reading.
The LTC4151 is said to replace prior solutions that use costly current sense amplifiers with a separate ADC, a hot-swap controller with an ADC, or an ADC with a floating ground. The company states that these older implementations are in many cases limited by the ADC’s input voltage range (typically 5 or 10V), are much more expensive, require more board space, and are not reliable. The LTC4151’s simple, single-chip solution is suitable for 48V telecom equipment, advanced mezzanine cards (AMC), and blade servers used for measuring input power over a wide input range. The device is also appropriate for power monitoring in industrial applications running at 12 or 24V.
The maximum total unadjusted error (TUE) for the high-side current and voltage measurements is ±1.25% over the -40 to +85°C industrial temperature range. A 2-wire I²C-compatible interface reports the LTC4151’s input power data, as well as a third low voltage input, which can be used to measure a voltage from a thermistor or a fuse. Data can be reported continuously or in a no-latency single snapshot mode, for applications that only need to measure input power occasionally. The LTC4151 features a dedicated shutdown pin to reduce power dissipation by 10x, while its counterpart, the LTC4151-1, features split I²C data pins with an inverted output to drive optoisolators.
The LTC4151 and LTC4151-1 are both available today in MSOP-10 and 3 x 3mm DFN-10 packages, with pricing beginning at $2.60 in 1,000-piece quantities.
