Power-supervision IC measures regulator-input current, differential-output voltage
By Paul Rako, Technical Editor -- EDN, August 19, 2008
Summit Microelectronics’ new SMM151 power-supervision IC allows digital control and monitoring of any voltage regulator. The device monitors input current to the target regulator so there is no added impedance to the output rail. A differential pair that can accept 15V inputs performs the voltage sensing, which is accurate to ±1%; current-sensing accuracy is ±2%. The part operates from 2.7 to 5.5V of power and has an I2C (interintegrated-circuit) interface that allows system monitoring in real time with parameters that you can change using the I2C bus. The unit provides fault- and ready-status outputs and accepts margin commands on two dedicated pins or the I2C bus. The IC allows users to program limits for glitch-filter duration, margin delays, and response to fault conditions. A sister part, the SMM152, also has four general-purpose I/O pins. Developers can program the power-on state of these pins and store that information in nonvolatile memory within the IC. All family members have two comparators for detecting levels or providing window comparisons, and they target applications in computing and datacom equipment, servers, wireless routers, and other high-reliability systems.
The SMM151EV evaluation board works through a USB port with Summit’s Windows-based GUI (graphical user interface), which allows designers to set up the operating parameters and then program them into nonvolatile memory. Once designers define the device’s functions, they can extract a hex file from the evaluation board that allows Summit to provide the part in volume quantities.
The device operates in a 0 to 70 or a −40 to +85°C temperature range and comes in a 5×5-mm, 28-pad QFN package. The SMM151 and SMM152 sell for $3.49 and $3.79 (1000), respectively. Samples and the SMM151EV evaluation modules are available, and volume production has just begun.
