參數(shù)資料
型號(hào): DAC8408GPZ
廠商: ANALOG DEVICES INC
元件分類: DAC
英文描述: QUAD, PARALLEL, 8 BITS INPUT LOADING, 0.19 us SETTLING TIME, 8-BIT DAC, PDIP28
封裝: PLASTIC, DIP-28
文件頁數(shù): 15/16頁
文件大?。?/td> 219K
代理商: DAC8408GPZ
DAC8408
–8–
REV. A
CIRCUIT INFORMATION
The DAC8408 combines four identical 8-bit CMOS DACs
onto a single monolithic chip. Each DAC has its own reference
input, feedback resistor, and on-board data latches. It also fea-
tures a read/write function that serves as an accessible memory
location for digital-input data words. The DAC’s three-state
readback drivers place the data word back onto the data bus.
D/A CONVERTER SECTION
Each DAC contains a highly stable, silicon-chromium, thin-film,
R-2R resistor ladder network and eight pairs of current steering
switches. These switches are in series with each ladder resistor
and are single-pole, double-throw NMOS transistors; the gates
of these transistors are controlled by CMOS inverters. Figure 1
shows a simplified circuit of the R-2R resistor ladder section,
and Figure 2 shows an approximate equivalent switch circuit.
The current through each resistor leg is switched between IOUT 1
and IOUT 2. This maintains a constant current in each leg, re-
gardless of the digital input logic states.
Each transistor switch has a finite “ON” resistance that can in-
troduce errors to the DAC’s specified performance. These resis-
tances must be accounted for by making the voltage drop across
each transistor equal to each other. This is done by binarily-
scaling the transistor’s “ON” resistance from the most signifi-
cant bit (MSB) to the least significant bit (LSB). With 10 volts
applied at the reference input, the current through the MSB
switch is 0.5 mA, the next bit is 0.25 mA, etc.; this maintains a
constant 10 mV drop across each switch and the converter’s ac-
curacy is maintained. It also results in a constant resistance ap-
pearing at the DAC’s reference input terminal; this allows the
DAC to be driven by a voltage or current source, ac or dc of
positive or negative polarity.
Shown in Figure 3 is an equivalent output circuit for DAC A.
The circuit is shown with all digital inputs high. The leakage
current source is the combination of surface and junction leak-
ages to the substrate. The 1/256 current source represents the
constant 1-bit current drain through the ladder terminating re-
sistor. The situation is reversed with all digital inputs low, as
shown in Figure 4. The output capacitance is code dependent,
and therefore, is modulated between the low and high values.
Figure 1. Simplified D/A Circuit of DAC8408
Figure 2. N-Channel Current Steering Switch
Figure 3. Equivalent DAC Circuit (AII Digital Inputs HIGH)
相關(guān)PDF資料
PDF描述
DAC8531E/2K5G4 SERIAL INPUT LOADING, 12 us SETTLING TIME, 16-BIT DAC, PDSO8
DAC87H-CBI-VBI PARALLEL, WORD INPUT LOADING, 3 us SETTLING TIME, 12-BIT DAC, CDIP24
DAM15S500CLF 15 CONTACT(S), FEMALE, D SUBMINIATURE CONNECTOR, SOLDER
DAM15S500LF 15 CONTACT(S), FEMALE, D SUBMINIATURE CONNECTOR, SOLDER
DAM15S500MLF 15 CONTACT(S), FEMALE, D SUBMINIATURE CONNECTOR, SOLDER
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
DAC8408HP 制造商:Rochester Electronics LLC 功能描述:- Bulk 制造商:Analog Devices 功能描述:
DAC8411 制造商:TI 制造商全稱:Texas Instruments 功能描述:1.8V to 5.5V, 80mA, 14- and 16-Bit, Low-Power, Single-Channel,DIGITAL-TO-ANALOG CONVERTERS in SC70 Package
DAC8411EVM 功能描述:數(shù)據(jù)轉(zhuǎn)換 IC 開發(fā)工具 DAC8411 Eval Mod RoHS:否 制造商:Texas Instruments 產(chǎn)品:Demonstration Kits 類型:ADC 工具用于評(píng)估:ADS130E08 接口類型:SPI 工作電源電壓:- 6 V to + 6 V
DAC8411EVM 制造商:Texas Instruments 功能描述:Development Tool
DAC8411EVM-PDK 功能描述:數(shù)據(jù)轉(zhuǎn)換 IC 開發(fā)工具 DAC8411 Perf Demo Kit RoHS:否 制造商:Texas Instruments 產(chǎn)品:Demonstration Kits 類型:ADC 工具用于評(píng)估:ADS130E08 接口類型:SPI 工作電源電壓:- 6 V to + 6 V