参数资料
| 型号： | AD7394ARZ |
| 厂商： | Analog Devices Inc |
| 文件页数： | 12/12页 |
| 文件大小： | 0K |
| 描述： | IC DAC 12BIT SERIAL 3V 14SOIC |
| 产品培训模块： | Data Converter Fundamentals DAC Architectures |
| 产品变化通告： | Product Discontinuance 27/Oct/2011 |
| 标准包装： | 56 |
| 设置时间： | 60µs |
| 位数： | 12 |
| 数据接口： | 串行 |
| 转换器数目： | 2 |
| 电压电源： | 单电源 |
| 功率耗散（最大）： | 1mW |
| 工作温度： | -40°C ~ 85°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 14-SOIC（0.154"，3.90mm 宽） |
| 供应商设备封装： | 14-SOICN |
| 包装： | 管件 |
| 输出数目和类型： | 2 电压，单极；2 电压，双极 |
| 采样率（每秒）： | 17k |
AD7394/AD7395
–9–
REV. 0
OPERATION
The AD7394 and AD7395 are a set of pin compatible, dual,
12-bit/10-bit digital-to-analog converters. These single-supply
operation devices consume less than 200 microamps of current
while operating from power supplies in the +2.7 V to +5.5 V
range, making them ideal for battery operated applications.
They contain a voltage-switched, 12-bit/10-bit, laser trimmed
digital-to-analog converter, rail-to-rail output op amps, two
DAC registers and a serial input shift register. The external
reference input has constant input resistance independent of the
digital code setting of the DAC. In addition, the reference input
can be tied to the same supply voltage as VDD, resulting in a
maximum output voltage span of 0 to VDD. The serial interface
consists of a serial data input (SDI), clock (CLK) and chip
select pin (
CS) and two load DAC Register pins (LDA and
LDB). A reset (RS) pin is available to reset the DAC register to
zero scale or midscale, depending on the digital level applied to
the MSB pin. This function is useful for power-on reset or
system failure recovery to a known state. Additional power
savings are accomplished by activating the
SHDN pin resulting
in a 1.5
A maximum consumption sleep mode.
D/A CONVERTER SECTION
The voltage switched R-2R DAC generates an output voltage
dependent on the external reference voltage connected to the
REF pin according to the following equation:
VOUT
=
V REF
× D
2
N
(1)
where D is the decimal data word loaded into the DAC register
and N is the number of bits of DAC resolution. In the case of
the 10-bit AD7395 using a 2.5 V reference, Equation 1 simpli-
fies to:
VOUT
=
2.5
× D
1024
(2)
Using Equation 2 the nominal midscale voltage at VOUT is
1.25 V for D = 512; full-scale voltage is 2.497 V. The LSB step
size is = 2.5
× 1/1024 = 0.0024 V.
For the 12-bit AD7394 operating from a 5.0 V reference Equa-
tion 1 becomes:
VOUT
=
5.0
× D
4096
(3)
Using Equation 3 the AD7394 provides a nominal midscale
voltage of 2.50 V for D = 2048, and a full-scale output of
4.998 V. The LSB step size is = 5.0
× 1/4096 = 0.0012 V.
AMPLIFIER SECTION
The internal DAC’s output is buffered by a low power con-
sumption precision amplifier. The op amp has a 60
s typical
settling time to 0.1% of full scale. There are slight differences in
settling time for negative slewing signals versus positive. Also,
negative transition settling time to within the last 6 LSBs of zero
volts has an extended settling time. The rail-to-rail output stage
of this amplifier has been designed to provide precision perfor-
mance while operating near either power supply. Figure 20
shows an equivalent output schematic of the rail-to-rail-ampli-
fier with its N-channel pull-down FETs that will pull an output
load directly to GND. The output sourcing current is provided
by a P-channel pull-up device that can source current to GND
terminated loads.
N-CH
VDD
VOUT
AGND
P-CH
Figure 20. Equivalent Analog Output Circuit
The rail-to-rail output stage provides more than
±1 mA of out-
put current. The N-channel output pull-down MOSFET shown
in Figure 20 has a 35
ON resistance, which sets the sink cur-
rent capability near ground. In addition to resistive load driving
capability, the amplifier has also been carefully designed and
characterized for up to 100 pF capacitive load driving capability.
REFERENCE INPUT
The reference input terminal has a constant input resistance
independent of digital code which results in reduced glitches on
the external reference voltage source. The high 2.5 M
input
resistance minimizes power dissipation within the AD7394/
AD7395 D/A converters. The VREF input accepts input voltages
ranging from ground to the positive supply voltage VDD. One of
the simplest applications, which saves an external reference
voltage source, is connection of the VREF terminal to the positive
VDD supply. This connection results in a rail-to-rail voltage
output span maximizing the programmed range. The reference
input will accept ac signals as long as they are kept within the
supply voltage range, 0 < VREF < VDD. The reference bandwidth
and integral nonlinearity error performance are plotted in the
Typical Performance Characteristics section (see Figures 8 and
18). The ratiometric reference feature makes the AD7394/AD7395
an ideal companion to ratiometric analog-to-digital converters
such as the AD7896.
相关PDF资料 |
PDF描述 |
|---|---|
| AD7398BR | IC DAC 12BIT QUAD SRL 16-SOIC |
| AD7401AYRWZ-RL | IC MODULATOR SIGMA-DELTA 16SOIC |
| AD7401YRWZ | IC MODULATOR SIGMA-DELTA 16SOIC |
| AD7450ABRT-R2 | IC ADC 12BIT W/DIFF INP SOT-23-8 |
| AD7450BRMZ | IC ADC 12BIT DIFF IN 1MSPS 8MSOP |
相关代理商/技术参数 |
参数描述 |
|---|---|
| AD7394ARZ-REEL7 | 功能描述:IC DAC 12BIT SERIAL 3V 14SOIC RoHS:是 类别:集成电路 (IC) >> 数据采集 - 数模转换器 系列:- 标准包装:2,400 系列:- 设置时间:- 位数:18 数据接口:串行 转换器数目:3 电压电源:模拟和数字 功率耗散（最大）:- 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:36-TFBGA 供应商设备封装:36-TFBGA 包装:带卷 (TR) 输出数目和类型:* 采样率（每秒）:* |
| AD7395 | 制造商:AD 制造商全称:Analog Devices 功能描述:+3 V, Dual, Serial Input 12-/10-Bit DACs |
| AD7395AN | 制造商:Rochester Electronics LLC 功能描述:X2, 10-BIT, +3V UPWR DAC - Bulk 制造商:Analog Devices 功能描述:10BIT DAC MICROPOWER 7395 DIP14 |
| AD7395AR | 制造商:Rochester Electronics LLC 功能描述:X2, 10-BIT, +3V UPWR DAC - Bulk |
| AD7395AR-REEL7 | 制造商:Rochester Electronics LLC 功能描述:- Tape and Reel |
发布紧急采购，3分钟左右您将得到回复。