原标题：ADI AD5770R六路14位低噪音DAC光学控制应用方案

　　ADI公司的AD5770R是六路14位分辨率低噪音可编电流输出的数模转换器(DAC)光学控制应用器件,采用1.25V片上基准电压,2.5 kΩ精密电阻作为基准电流产生,芯片温度,输出监测功能,故障告警和重置功能.AD5770R包含5个14位分辨率电流源DAC通路和一个14位分辨率电流源和沉的DAC通路:通路0可配置成多达60mA的沉和多达300mA的源,而通路1到5有多个可编输出电流源范围由寄存器存储来定;每个DAC工作在0.8V到AVDD -0.4V电源轨内,以优化电源效率和热消耗.AD5770R工作电压从2.9V到5.5V AVDD电源,工作温度−40℃到+105℃,具有SPI接口,主要工作在光学控制,LED驱动器可编电流源和电流模式偏置.本文介绍了AD5770R主要特性,功能框图以及评估板EVAL-AD5770RSDZ主要特性,加电图和电路图以及材料清单.

　　The AD5770R is a 6-channel, 14-bit resolution, low noise, programmable current output, digital-to-analog converter (DAC) for photonics control applications. The device incorporates a 1.25 V, on-chip voltage reference, a 2.5 kΩ precision resistor for reference current generation, die temperature, output monitoring functions, fault alarm, and reset functions.

　　The AD5770R contains five 14-bit resolution current sourcing DAC channels and one 14-bit resolution current sourcing and sinking DAC channel.

　　Channel 0 can be configured to sink up to 60 mA and source up to 300 mA. Channel 1 to Channel 5 have multiple programmable output current sourcing ranges set by register access.

　　Each DAC operates with a wide power supply rail from 0.8 V to AVDD − 0.4 V for optimizing power efficiency and thermal power dissipation.

　　The AD5770R operates from a 2.9 V to 5.5 V AVDD supply and is specified over the −40℃ to +105℃ temperature range.

　　AD5770R主要特性:

　　6-channel, current output DAC

　　14-bit resolution

　　Programmable output current ranges

　　Channel 0: 0 mA to 300 mA, −60 mA to +300 mA, −60 mA to 0 mA

　　Channel 1: 0 mA to 140 mA, 0 mA to 250 mA

　　Channel 2: 0 mA to 55 mA, 0 mA to 150 mA

　　Channel 3, Channel 4, Channel 5: 0 mA to 45 mA, 0 mA to 100 mA

　　All current sourcing output ranges scale back by up to 0.5×

　　1.25 V, on-chip voltage reference

　　Integrated precision reference resistor

　　SPI interface

　　Reset function

　　Output current monitor

　　Compliance voltage monitor

　　Die temperature monitor

　　Integrated thermal shutdown

　　49-ball,4 mm × 4 mm WLCSP package

　　Operating temperature: −40℃ to +105℃

　　AD5770R应用:

　　Photonics control

　　LED driver programmable current source

　　Current mode biasing

　　图1.AD5770R功能框图

　　评估板EVAL-AD5770RSDZ

　　The EVAL-AD5770RSDZ is a fully featured evaluation board that is designed to help the user evaluate the AD5770R 6-channel, 14-bit, current output digital-to-analog converter (DAC).

　　The EVAL-AD5770RSDZ evaluation board is controlled by the following two methods: the on-board P11 connector and the EVAL-SDP-CB1Z (Connector P10). The system development (SDP-B) board uses the AD5770R evaluation software to control the EVAL-AD5770RSDZ evaluation board via a Windows® PC USB port.

　　The EVAL-AD5770RSDZ board contains a power solution that uses the ADP5073 switching regulator to generate −2 V from a +3.3 V supply and the ADP1741 linear regulator to generate +2 V from a +3.3 V supply. Alternatively, the AD5770R also uses a linear power supply connected through the nine on-board connectors (P0 to P8). The AD5770R incorporates an internal 1.25 V precision reference. The EVAL-AD5770RSDZ board contains an additional 1.25, V 0.5 ppm/°C voltage reference.

　　The AD5770R evaluation software provides an intuitive graphic user interface (GUI) that configures and controls the AD5770R over the serial peripheral interface (SPI).

　　The AD5770R is a 6-channel, 14-bit resolution, low noise, programmable current output DAC for photonics control applications. The output current ranges are software selectable, and channels are routed to the MUX_OUT pin for external monitoring.

　　See the AD5770R data sheet for full details and consult the AD5770R data sheet in conjunction with this user guide when using the EVAL-AD5770RSDZ board.

　　评估板EVAL-AD5770RSDZ主要特性:

　　Fully featured evaluation board for the AD5770R

　　PC control in conjunction with Analog Devices® Inc., EVAL-SDP-CB1Z system development platform

　　PC software for control

　　图2.评估板EVAL-AD5770RSDZ外形图

　　图3.评估板EVAL-AD5770RSDZ加电图

　　图4.评估板EVAL-AD5770RSDZ电路图-主器件和PMOD连接(1)

　　图5.评估板EVAL-AD5770RSDZ电路图-主器件和PMOD连接(2)

连接器" src="https://supp.iczoom.com/images/public/201909/1569564695563046286.png" title="图6.评估板EVAL-AD5770RSDZ电路图-SDP接口连接器" style="width: 554px; height: 432px;" width="554" vspace="0" height="432" border="0"/>

　　图6.评估板EVAL-AD5770RSDZ电路图-SDP接口连接器

　　评估板EVAL-AD5770RSDZ材料清单: