ADI AD5780 18位数模转换解决方案

2012年04月23日 21:23    发布者:1046235000
ADI公司的AD5780是18位电压输出数模转换器(DAC),工作电压为双极电源,高达33V,正基准电压为5V到VDD-2.5V,负基准电压为VSS+2.5V到0V, 0°C到+125℃工作温度,低噪音为8 nV/√Hz,增益误差温度系数为±0.018 ppm/℃,主要用在医疗仪器,测试和测量,工业控制,科学和航空仪表,数据采集系统,数字增益和失调调整以及电源控制.本文介绍了AD5780主要特性和产品亮点, 方框图和典型应用电路,以及评估板EVAL-AD5780主要特性,方框图,电路图,材料清单和PCB布局图.

The AD5780 is a true 18-bit, unbuffered voltage output DAC that operates from a bipolar supply of up to 33 V. The AD5780 accepts a positive reference input range of 5 V to VDD − 2.5 V and a negative reference input range of VSS + 2.5 V to 0 V. Both reference inputs are buffered on chip and external buffers are not required. The AD5780 offers a relative accuracy specification of ±1 LSB maximum range, and operation is guaranteed monotonic with a ±1 LSB DNL maximum range specification.

The part uses a versatile 3-wire serial interface that operates at clock rates of up to 35 MHz and is compatible with standard SPI, QSPI™ MICROWIRE™ and DSP interface standards. The part incorporates a power-on reset circuit that ensures that the DAC output powers up to 0 V in a known output impedance state and remains in this state until a valid write to the device takes place. The part provides an output clamp feature that places the output in a defined load state.

AD5780产品亮点:

True 18-bit accuracy.

Wide power supply range of up to ±16.5 V.

−0℃ to +125℃ operating temperature range.

Low 8 nV/√Hz noise.

Low ±0.018 ppm/℃ gain error temperature coefficient.

AD5780主要特性:

True 18-bit voltage output DAC, ±1 LSB INL

8 nV/√Hz output noise spectral density

0.025 LSB long-term linearity error stability

±0.018 ppm/℃ gain error temperature coefficient

2.5 μs output voltage settling time

3.5 nV-sec midscale glitch impulse

Integrated precision reference buffers

Operating temperature range: −0℃ to +125℃

4 mm × 5 mm LFCSP package

Wide power supply range of up to ±16.5 V

35 MHz Schmitt triggered digital interface

1.8 V-compatible digital interface

AD5780应用:

Medical instrumentation

Test and measurement

Industrial control

Scientific and aerospace instrumentation

Data acquisition systems

Digital gain and offset adjustment

Power supply control

图1.AD5780方框图

图2.AD5780典型应用电路图

评估板EVAL-AD5780

The EVAL-AD5780 is a full-featured evaluation board, designed to allow the user to easily evaluate all features of the AD5780 voltage output, 18-bit digital-to-analog converter (DAC). The AD5780 pins are accessible at on-board connectors for external connection. The board can be controlled by two means: via the on-board connector (J3), or via the system development platform connector (J4). The SDP board allows the evaluation board to be controlled through the USB port of a Windows® XP- (SP2 or later) or Vista-based (32-bit) PC using the AD5780 evaluation software.

图3.评估板EVAL-AD5780外形图

评估板EVAL-AD5780主要特性:

Full-featured evaluation board for the AD5780

Link options

PC control in conjunction with Analog Devices, Inc., system development platform

PC software for control

图4.评估板EVAL-AD5780功能方框图

图5.评估板EVAL-AD5780电路图(1)

图6.评估板EVAL-AD5780电路图(2)

图7.评估板EVAL-AD5780电路图:SDP板连接器

评估板EVAL-AD5780材料清单(BOM):



图8.评估板EVAL-AD5780 PCB元件布局图

图9.评估板EVAL-AD5780 PCB顶层布局图
详情请见:
74618和
74619

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