參數(shù)資料
型號(hào): AD8303AR
廠商: ANALOG DEVICES INC
元件分類(lèi): DAC
英文描述: +3 V, Dual, Serial Input Complete 12-Bit DAC
中文描述: DUAL, SERIAL INPUT LOADING, 14 us SETTLING TIME, 12-BIT DAC, PDSO14
封裝: 1.75 MM HEIGHT, SOIC-14
文件頁(yè)數(shù): 8/16頁(yè)
文件大?。?/td> 414K
代理商: AD8303AR
AD8303
REV. 0
–8–
THEORY OF OPERATION
The AD8303 is a complete, ready-to-use, dual, 12-bit digital-to-
analog converter. Only one +2.7 V to +5.5 V power supply is
necessary for operation. It contains two voltage-switched, 12-bit,
laser-trimmed digital-to-analog converters, a curvature-
corrected bandgap reference, rail-to-rail output op amps, input
shift register, and two DAC registers. The serial data interface
consists of a serial data input (SDI), clock (CLK), chip select
(
CS
) and two DAC load strobe pins (
LDA
and
LDB
).
For battery operation and similar low power applications, a
shutdown feature (
SHDN
) is available to reduce power supply
current to less than 1
μ
A. In addition an asynchronous reset pin
(
RS
) will set both DAC outputs to either zero volts or to
midscale, depending on the logic value applied to the MSB pin.
This function is useful for power-on reset or system failure
recovery to a known state.
D/A CONVERTER SECTION
Each of the two DACs is a 12-bit device with an output that
swings from GND potential to 0.4 V generated from the internal
bandgap voltage (Figure 22). Each DAC uses a laser-trimmed
segmented R-2R ladder that is switched by n-channel
MOSFETs. The output voltage of the DAC has a constant
resistance independent of digital input code. The DAC output is
internally connected to the rail-to-rail output op amp.
12-BIT DAC
2.5k
10k
V
2.047V
FS
BANDGAP
REF
1.0V
0.4V
0.4V
FS
V
1.0V
2k
10k
Figure 22. AD8303 Equivalent Schematic of Analog Section
AMPLIFIER SECTION
The internal DAC’s output is buffered by a low power
consumption, precision amplifier. This low power amplifier
contains a differential PNP pair input stage that provides low
offset voltage and low noise, as well as the ability to amplify the
zero-scale DAC output voltages, The rail-to-rail amplifier is
configured with a gain of approximately five in order to set the
2.0475 volt full-scale output (0.5 mV/LSB). An equivalent
circuit schematic for the amplifier section is shown in Figure 22.
The op amp has a 4
μ
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. See the oscilloscope photos in the typical performances
section of this data sheet.
OUTPUT SECTION
The rail-to-rail output stage of this amplifier has been designed
to provide precision performance while operating near either
power supply. Figure 23 shows an equivalent output schematic
of the rail-to-rail amplifier 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.
The rail-to-rail output stage permits operation at supply
voltages down to +2.7 V. The N-channel output pull-down
MOSFET shown in Figure 23 has a 35
ON resistance which
sets the sink current capability near ground. In addition to
resistive load driving capability, the amplifier has also been
carefully designed and characterized for up to 500 pF capacitive
load driving capability.
P-CH
N-CH
V
DD
V
OUT
AGND
Figure 23. Equivalent Analog Output Circuit
REFERENCE SECTION
The internal curvature-corrected bandgap voltage reference is
laser trimmed for both initial accuracy and low temperature
coefficient. Figure 18 provides a histogram of total output
performance of full-scale versus temperature, which is dominated
by the reference performance.
V
REF
Output
The internal reference drives two resistor-divider networks. One
divider provides a 0.4 V reference for the DAC. The second
divider is trimmed to 1.0 V and is available at the V
REF
pin. The
V
REF
output is useful for ratiometric applications, and also for
generating a “false ground” or bipolar offset. See Figures 30
and Figure 31 for typical applications. Since V
REF
has a high
output impedance, it must be buffered if it is required to deliver
current to an external load.
相關(guān)PDF資料
PDF描述
AD8309 5 MHz to 500 MHz 100 dB Demodulating Logarithmic Amplifier with Limiter Output(具有限幅輸出為的5MHz到500MHz,輸入動(dòng)態(tài)范圍為100dB的解調(diào)對(duì)數(shù)放大器)
AD8310 Fast, Voltage-Out DC-440 MHz 95 dB Logarithmic Amplifier
AD8310-EVAL Fast, Voltage-Out DC-440 MHz 95 dB Logarithmic Amplifier
AD8310ARM Fast, Voltage-Out DC-440 MHz 95 dB Logarithmic Amplifier
AD8310ARM-REEL Fast, Voltage-Out DC-440 MHz 95 dB Logarithmic Amplifier
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
AD8303AR-REEL 制造商:Analog Devices 功能描述:DAC 2-CH R-2R 12-bit 14-Pin SOIC N T/R 制造商:Rochester Electronics LLC 功能描述:IC,DUAL 12BIT,+3V,COMPLETE DAC,TAPE&REEL - Tape and Reel
AD8303ARZ-REEL 功能描述:IC DAC 12BIT SERIAL 14SOIC RoHS:是 類(lèi)別:集成電路 (IC) >> 數(shù)據(jù)采集 - 數(shù)模轉(zhuǎn)換器 系列:- 標(biāo)準(zhǔn)包裝:2,400 系列:- 設(shè)置時(shí)間:- 位數(shù):18 數(shù)據(jù)接口:串行 轉(zhuǎn)換器數(shù)目:3 電壓電源:模擬和數(shù)字 功率耗散(最大):- 工作溫度:-40°C ~ 85°C 安裝類(lèi)型:表面貼裝 封裝/外殼:36-TFBGA 供應(yīng)商設(shè)備封裝:36-TFBGA 包裝:帶卷 (TR) 輸出數(shù)目和類(lèi)型:* 采樣率(每秒):*
AD8303JRU 制造商:Analog Devices 功能描述:DAC 2-CH R-2R 12-bit 14-Pin TSSOP 制造商:Rochester Electronics LLC 功能描述:IC,DUAL 12BIT,+3V,COMPLETE DAC - Bulk
AD8303JRU-REEL 制造商:Analog Devices 功能描述:DAC 2-CH R-2R 12-bit 14-Pin TSSOP T/R
AD8303JRUZ 制造商:Analog Devices 功能描述:DAC 2-CH R-2R 12-bit 14-Pin TSSOP