AD7741BR

更新时间： 2024-02-16 00:10:56

品牌	Logo	应用领域
亚德诺 - ADI		转换器模拟特殊功能转换器光电二极管
页数	文件大小	规格书
12页	134K
描述
Single and Multichannel, Synchronous Voltage-to-Frequency Converters

阅读下载

获取价格

技术参数
数据手册

如果您发现信息不准确，欢迎纠错

AD7741BR 技术参数

是否无铅：	含铅	是否Rohs认证：	符合
生命周期：	Active	零件包装代码：	SOIC
包装说明：	SOP,	针数：	8
Reach Compliance Code：	compliant	ECCN代码：	EAR99
HTS代码：	8542.39.00.01	风险等级：	5.29
转换器类型：	VOLTAGE TO FREQUENCY CONVERTER	JESD-30 代码：	R-PDSO-G8
JESD-609代码：	e3	长度：	4.9 mm
最大线性误差 (EL)：	0.024%	湿度敏感等级：	1
功能数量：	1	端子数量：	8
最大工作频率：	6.144 MHz	最高工作温度：	105 °C
最低工作温度：	-40 °C	封装主体材料：	PLASTIC/EPOXY
封装代码：	SOP	封装形状：	RECTANGULAR
封装形式：	SMALL OUTLINE	峰值回流温度（摄氏度）：	260
最大正输入电压：	2.5 V	认证状态：	Not Qualified
座面最大高度：	2.59 mm	最大供电电压：	5.25 V
最小供电电压：	4.75 V	标称供电电压：	5 V
表面贴装：	YES	技术：	CMOS
温度等级：	INDUSTRIAL	端子面层：	Matte Tin (Sn)
端子形式：	GULL WING	端子节距：	1.27 mm
端子位置：	DUAL	处于峰值回流温度下的最长时间：	30
宽度：	3.9 mm	Base Number Matches：	1

AD7741BR 数据手册

AD7741/AD7742

The digital data that represents the analog input voltage is con-

tained in the duty cycle of the pulse train appearing at the out-

put of the comparator. The output is a fixed-width pulse whose

frequency depends on the analog input signal. The input voltage

is offset internally so that a full-scale input gives an output fre-

quency of 0.45 f_CLKINand zero-scale input gives an output fre-

quency of 0.05 f_CLKIN. The output allows simple interfacing to

either standard logic families or opto-couplers. The clock high

period controls the pulsewidth of the frequency output. The

pulse is initiated by the edge of the clock signal. The delay time

between the edge of the clock and the edge of the frequency

output is typically 9 ns. Figure 7 shows the waveform of this

frequency output.

AD7741/AD7742

TO OTHER

CIRCUITRY

5M⍀

CLKIN

CLKOUT

Figure 8. On-Chip Oscillator

The on-chip oscillator circuit also has a start-up time associated

with it before it oscillates at its correct frequency and correct

voltage levels. The typical start-up time for the circuit is 5 ms

(with a 6.144 MHz crystal).

After power-up, or if there is a step change in input voltage,

there is a settling time that must elapse before valid data is

obtained. This is typically 2 CLKIN cycles on the AD7742 and

10 CLKIN cycles on the AD7741.

The AD7741/AD7742 master clock appears on the CLKOUT

pin of the device. The maximum recommended load on this pin

is one CMOS load. When using a crystal to generate the AD7741/

AD7742 clock it may be desirable to then use this clock as the

clock source for the system. In this case it is recommended that

the CLKOUT signal be buffered with a CMOS buffer before

being applied to the rest of the circuit.

CLKIN

= f

OUT

CLKIN

= V

REF

= f

/10

OUT

CLKIN

= V

Reference Input

REF

The AD7741/AD7742 performs conversion relative to an applied

reference voltage that allows easy interfacing to ratiometric

systems. This reference may be applied using the internal 2.5 V

bandgap reference. For the AD7741, this is done by simply

leaving REFIN/OUT unconnected. For the AD7742, REFIN is

tied to REFOUT. Alternatively, an external reference, e.g.,

REF192 or AD780, may be used. For the AD7741, this is con-

nected to REFIN/OUT and will overdrive the internal refer-

ence. For the AD7742, it is connected directly to the REFIN

pin.

= f

*3/20

REF

OUT

CLKIN

= V

6 T

7 T

CLK

AVERAGE f

VARIES BETWEEN f

IS f

*3/20 BUT THE ACTUAL PULSE STREAM

OUT

CLKIN

/6 AND f

CLKIN

Figure 7. AD7741/AD7742 Frequency Output Waveforms

Clock Generation

As distinct from the asynchronous VFCs which rely on the stability

of an external capacitor to set their full-scale frequency, the

AD7741/AD7742 uses an external clock to define the full-scale

output frequency. The result is a more stable, more linear trans-

fer function and also allows the designer to determine the sys-

tem stability and drift based upon the external clock selected. A

crystal oscillator may also be used if desired.

While the internal reference will be adequate for most applica-

tions, power supply rejection and overall regulation may be

improved through the use of an external precision reference.

The process of selecting an external voltage reference should

include consideration of drive capability, initial error, noise and

drift characteristics. A suitable choice would be the AD780 or

REF192.

The AD7741/AD7742 requires a master clock input, which may

be an external CMOS-compatible clock signal applied to the

CLKIN pin (CLKOUT not used). Alternatively, a crystal of the

correct frequency can be connected between CLKIN and

CLKOUT, when the clock circuit will function as a crystal

controlled oscillator. Figure 8 shows a simple model of the on-

chip oscillator.

Power-Down Mode

The low power standby mode is initiated by taking the PD pin

low, which shuts down most of the analog and digital circuitry.

This reduces the power consumption to 185 µW max.

REV. 0

–9–

1...6 7 8910 11 12

下载PDF

与AD7741BR相关器件

型号	品牌	描述	获取价格	数据表
AD7741BR-REEL	ADI	VOLTAGE-FREQUENCY CONVERTER, 6.144MHz, PDSO8, SOIC-8	获取价格
AD7741BRZ	ADI	Single and Multichannel, Synchronous Voltage-to-Frequency Converters	获取价格
AD7741BRZ-REEL7	ADI	Single and Multichannel, Synchronous Voltage-to-Frequency Converters	获取价格
AD7741YR	ADI	Single and Multichannel, Synchronous Voltage-to-Frequency Converters	获取价格
AD7741YR-REEL7	ADI	VOLTAGE-FREQUENCY CONVERTER, 6.144MHz, PDSO8, 0.150 INCH, SOIC-8	获取价格
AD7741YRZ	ADI	Single and Multichannel, Synchronous Voltage-to-Frequency Converters	获取价格

与AD7741BR相关文章

SG3525资料手册详解：SG3525参数分析、引脚说明、应用介绍
2024-05-23

5
AT89C51单片机资料手册详细解析及应用示例
2024-05-23

8
CP2102资料手册解读：CP2102引脚说明、关键参数分析
2024-05-23

4
资料手册解读：UC3842参数和管脚说明
2024-05-22

5

产品中心

服务支持

精选活动

关于我们

帮助中心

AD7741BR

AD7741BR 技术参数

AD7741BR 数据手册

与AD7741BR相关器件

与AD7741BR相关文章

您还可以找

产品中心

服务支持

精选活动

关于我们

帮助中心

AD7741BR

AD7741BR 技术参数

AD7741BR 数据手册

与AD7741BR相关器件

与AD7741BR相关文章

您还可以找

您在本页遇到什么问题？