参数资料
| 型号： | AD9740ARUZ |
| 厂商： | Analog Devices Inc |
| 文件页数： | 5/32页 |
| 文件大小： | 0K |
| 描述： | IC DAC 10BIT 210MSPS 28-TSSOP |
| 产品培训模块： | Data Converter Fundamentals DAC Architectures |
| 标准包装： | 50 |
| 系列： | TxDAC® |
| 设置时间： | 11ns |
| 位数： | 10 |
| 数据接口： | 并联 |
| 转换器数目： | 1 |
| 电压电源： | 模拟和数字 |
| 功率耗散（最大）： | 145mW |
| 工作温度： | -40°C ~ 85°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 28-TSSOP（0.173"，4.40mm 宽） |
| 供应商设备封装： | 28-TSSOP |
| 包装： | 管件 |
| 输出数目和类型： | 2 电流，单极；2 电流，双极 |
| 采样率（每秒）： | 210M |
| 产品目录页面： | 785 (CN2011-ZH PDF) |
| 配用： | AD9740ACP-PCBZ-ND - BOARD EVAL FOR AD9740ACP |
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AD9740
Rev. B | Page 13 of 32
FUNCTIONAL DESCRIPTION
Figure 22 shows a simplified block diagram of the AD9740. The
AD9740 consists of a DAC, digital control logic, and full-scale
output current control. The DAC contains a PMOS current
source array capable of providing up to 20 mA of full-scale
current (IOUTFS). The array is divided into 31 equal currents that
make up the five most significant bits (MSBs). The next four
bits, or middle bits, consist of 15 equal current sources whose
value is 1/16 of an MSB current source. The remaining LSBs are
binary weighted fractions of the middle bits current sources.
Implementing the middle and lower bits with current sources,
instead of an R-2R ladder, enhances its dynamic performance
for multitone or low amplitude signals and helps maintain the
DAC’s high output impedance (that is, >100 kΩ).
All of these current sources are switched to one or the other of
the two output nodes (that is, IOUTA or IOUTB) via PMOS
differential current switches. The switches are based on the
architecture that was pioneered in the AD9764 family, with
further refinements to reduce distortion contributed by the
switching transient. This switch architecture also reduces
various timing errors and provides matching complementary
drive signals to the inputs of the differential current switches.
The analog and digital sections of the AD9740 have separate
power supply inputs (that is, AVDD and DVDD) that can
operate independently over a 2.7 V to 3.6 V range. The digital
section, which is capable of operating at a clock rate of up to
210 MSPS, consists of edge-triggered latches and segment
decoding logic circuitry. The analog section includes the PMOS
current sources, the associated differential switches, a 1.2 V
band gap voltage reference, and a reference control amplifier.
The DAC full-scale output current is regulated by the reference
control amplifier and can be set from 2 mA to 20 mA via an
external resistor, RSET, connected to the full-scale adjust
(FS ADJ) pin. The external resistor, in combination with both
the reference control amplifier and voltage reference, VREFIO, sets
the reference current, IREF, which is replicated to the segmented
current sources with the proper scaling factor. The full-scale
current, IOUTFS, is 32 times IREF.
REFERENCE OPERATION
The AD9740 contains an internal 1.2 V band gap reference. The
internal reference cannot be disabled, but can be easily overridden
by an external reference with no effect on performance. Figure 23
shows an equivalent circuit of the band gap reference. REFIO
serves as either an output or an input depending on whether
the internal or an external reference is used. To use the internal
reference, simply decouple the REFIO pin to ACOM with a
0.1 μF capacitor and connect REFLO to ACOM via a resistance
less than 5 Ω. The internal reference voltage is present at
REFIO. If the voltage at REFIO is to be used anywhere else in
the circuit, then an external buffer amplifier with an input bias
current of less than 100 nA should be used. An example of the
use of the internal reference is shown in Figure 24.
AVDD
7k
84A
REFLO
REFIO
0
291
1-
05
7
Figure 23. Equivalent Circuit of Internal Reference
150pF
1.2V REF
AVDD
REFLO
CURRENT
SOURCE
ARRAY
3.3V
REFIO
FS ADJ
2k
Ω
0.1
μF
AD9740
ADDITIONAL
LOAD
OPTIONAL
EXTERNAL
REF BUFFER
02911-
022
Figure 24. Internal Reference Configuration
An external reference can be applied to REFIO, as shown in
Figure 25. The external reference can provide either a fixed
reference voltage to enhance accuracy and drift performance
or a varying reference voltage for gain control. Note that the
0.1 μF compensation capacitor is not required because the
internal reference is overridden, and the relatively high input
impedance of REFIO minimizes any loading of the external
reference.
相关PDF资料 |
PDF描述 |
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| AD5308BRUZ | IC DAC 8BIT OCTAL W/BUFF 16TSSOP |
相关代理商/技术参数 |
参数描述 |
|---|---|
| AD9740ARUZ1 | 制造商:AD 制造商全称:Analog Devices 功能描述:10-Bit, 210 MSPS TxDAC D/A Converter |
| AD9740ARUZRL7 | 功能描述:IC DAC 10BIT 210MSPS 28-TSSOP RoHS:是 类别:集成电路 (IC) >> 数据采集 - 数模转换器 系列:TxDAC® 产品培训模块:LTC263x 12-, 10-, and 8-Bit VOUT DAC Family 特色产品:LTC2636 - Octal 12-/10-/8-Bit SPI VOUT DACs with 10ppm/°C Reference 标准包装:91 系列:- 设置时间:4µs 位数:10 数据接口:MICROWIRE?，串行，SPI? 转换器数目:8 电压电源:单电源 功率耗散（最大）:2.7mW 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:14-WFDFN 裸露焊盘 供应商设备封装:14-DFN-EP（4x3） 包装:管件 输出数目和类型:8 电压，单极 采样率（每秒）:* |
| AD9740ARZ | 功能描述:IC DAC 10BIT 210MSPS 28-SOIC RoHS:是 类别:集成电路 (IC) >> 数据采集 - 数模转换器 系列:TxDAC® 标准包装:1 系列:- 设置时间:4.5µs 位数:12 数据接口:串行，SPI? 转换器数目:1 电压电源:单电源 功率耗散（最大）:- 工作温度:-40°C ~ 125°C 安装类型:表面贴装 封装/外壳:8-SOIC（0.154"，3.90mm 宽） 供应商设备封装:8-SOICN 包装:剪切带 (CT) 输出数目和类型:1 电压，单极；1 电压，双极 采样率（每秒）:* 其它名称:MCP4921T-E/SNCTMCP4921T-E/SNRCTMCP4921T-E/SNRCT-ND |
| AD9740ARZRL | 功能描述:IC DAC 10BIT 210MSPS 28-SOIC RoHS:是 类别:集成电路 (IC) >> 数据采集 - 数模转换器 系列:TxDAC® 产品培训模块:LTC263x 12-, 10-, and 8-Bit VOUT DAC Family 特色产品:LTC2636 - Octal 12-/10-/8-Bit SPI VOUT DACs with 10ppm/°C Reference 标准包装:91 系列:- 设置时间:4µs 位数:10 数据接口:MICROWIRE?，串行，SPI? 转换器数目:8 电压电源:单电源 功率耗散（最大）:2.7mW 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:14-WFDFN 裸露焊盘 供应商设备封装:14-DFN-EP（4x3） 包装:管件 输出数目和类型:8 电压，单极 采样率（每秒）:* |
| AD9740-EB | 制造商:Analog Devices 功能描述:10 BIT 100 MSPS CMOS DAC - Bulk |
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