Analog Devices Inc./Maxim Integrated

The AD7277 is a 10-bit, high speed, low power, successive-approximation ADC. The parts operate from a single 2.35 V to 3.6 V power supply and feature throughput rates of up to 3 MSPS. The parts contain a low noise, wide bandwidth track-and-hold amplifier that can handle input frequencies in excess of 55 MHz.The conversion process and data acquisition are controlled usingCSand the serial clock, allowing the devices to interface with microprocessors or DSPs. The input signal is sampled on the falling edge ofCS, and the conversion is also initiated at this point. There are no pipeline delays associated with the part.The AD7277 uses advanced design techniques to achieve very low power dissipation at high throughput rates.The reference for the part is taken internally from VDD. This allows the widest dynamic input range to the ADC; therefore, the analog input range for the part is 0 to VDD. The conversion rate is determined by the SCLK.PRODUCT HIGHLIGHTS3 MSPS ADCs in a 6-lead TSOT package.AD7476 / AD7477 / AD7478 and AD7476A / AD7477A / AD7478A pin-compatible.High throughput with low power consumption.Flexible power/serial clock speed management. This allows maximum power efficiency at low throughput rates.Reference derived from the power supply.No pipeline delay. The parts feature a standard successive approximation ADC with accurate control of the sampling instant via aCSinput and once-off conversion control.

The AD7280A contains all the functions required for general-purpose monitoring of stacked lithium ion batteries as used in hybrid electric vehicles, battery backup applications, and power tools. The part has multiplexed cell voltage and auxiliary ADC measurement channels for up to six cells of battery management. An internal ±3 ppm reference is provided that allows a cell voltage accuracy of ±1.6 mV. The ADC resolution is 12 bits and allows conversion of up to 48 cells within 7 μs.The AD7280A operates from just one VDDsupply that has a range of 8 V to 30 V (with an absolute maximum rating of 33 V). The part provides six differential analog input channels to accommodate large common-mode signals across the full VDDrange. Each channel allows an input signal range, VIN(+) − VIN(−), of 1 V to 5 V. The input pins assume a series stack of six cells. In addition, the part includes six auxiliary ADC input channels that can be used for temperature measurement or system diagnostics.The AD7280A includes on-chip registers that allow a sequence of channel measurements to be programmed to suit the applications requirements.The AD7280A also includes a dynamic alert function that can detect if the cell voltages or auxiliary ADC inputs exceed an upper or lower limit defined by the user. The AD7280A has cell balancing interface outputs designed to control external FET transistors to allow discharging of individual cells.The AD7280A includes a built in self-test feature that internally applies a known voltage to the ADC inputs.There is a daisy-chain interface that allows up to eight parts to be stacked without the need for individual device isolation.The AD7280A requires only one supply pin that takes 6.5 mA under normal operation, while converting at 1 MSPS.All this functionality is provided in a 48-lead LQFP package operating over a temperature range of −40°C to +105°C.APPLICATIONSLithium ion battery monitoringElectric and hybrid electric vehiclesPower supply back upPower tools