Maxim 公司的MAX11040是24位四路同时取样的sigma-delta ADC,采用内置的级联特性,同时取样可达32路. MAX11040单电源3V工作,在16ksps时的SNR为106dB,1ksps时SNR为117dB,具有SPI,QSPI,MICROWIRE和DSP兼容的4线串行接口,可广泛应用在电源保护中继设备,多相电源系统,工业数据采集系统和医疗设备.本文介绍了MAX11040的主要特性,方框图,典型工作电路以及多个MAX11040菊花连接方框图.

The MAX11040 is a 24-bit, 4-channel, simultaneous sampling, sigma-delta analog-to-digital converter (ADC). The device allows simultaneous sampling of as many as 32 channels using a built-in cascade feature to synchronize as many as eight devices. The serial interface of the MAX11040 allows reading data from all the cascaded devices using a single command. Four modulators simultaneously convert each fully differential analog input with a programmable data output rate ranging from 0.25ksps to 64ksps. The device achieves 106dB SNR at 16ksps and 117dB SNR at 1ksps. The MAX11040 operates from a single +3V supply. The differential analog input range is ±2.2V when using the internal reference, an external reference is optional.

Each input is overvoltage protected up to ±6V without damage. The device uses an internal crystal oscillator or an external source for clock.

The MAX11040 is compatible with SPI, QSPI, MICROWIRE, and DSP-compatible 4-wire serial interfaces. An on-board interface logic allows one serial interface (with a single chip select) to control up to eight cascaded devices or 32 simultaneous sampling analog input channels.

The MAX11040 is ideally suited for power-management systems. Each channel includes an adjustable sampling phase enabling internal compensation for phase shift due to external dividers, transformers, or filters at the inputs. The output data rate is adjustable with a 0.065% resolution (at 16ksps or below) to track the varying frequency of a periodic input. A SYNC input allows periodic alignment of the conversion timing of multiple devices with a remote timing source.

The MAX11040 is available in a 38-pin TSSOP package specified over the -40℃ to +105℃ industrial temperature range.

MAX11040主要特性:

Four Fully Differential Simultaneously Sampled Channels

Cascadable for Up to 32 Channels of Simultaneous Sampling

106dB SNR at 16ksps

117dB SNR at 1ksps

0.25% Error Over a 1000:1 Dynamic Range, Processed Over 16.7ms

±2.2V Full-Scale Input Range

±6V Overvoltage Protected Inputs

Internal Crystal Oscillator

2.5V, 50ppm/℃ Internal Reference or External Reference

Programmable Output Data Rate

0.25ksps to 64ksps Range 0.065% Resolution

Programmable Sampling Phase 0 to 333μs Delay in 1.33μs Steps

SPI-/QSPI-/MICROWIRE-/DSP-Compatible 4-Wire Serial Interface

Cascadable Interface Allows Control of Up to Eight Devices with a Single CS Signal

3.0V to 3.6V Analog Supply Voltage

2.7V to VAVDD Digital Supply Voltage

38-Pin TSSOP Package

Applications

Power Protection Relay Equipment

Multiphase Power Systems

Industrial Data-Acquisition Systems

Medical Instrumentation



图1.MAX11040功能方框图



图2.MAX11040典型工作电路



图3.多个MAX11040菊花连接方框图



图4.每个MAX11040一个晶振和最后器件驱动的全同步输入电路方框图