 |
データシートサーチシステム |
|
|
データシートサーチシステム |
|
AD5546 データシート(PDF) 10 Page - Analog Devices |
|
||||||||||||||||||||||||||||||
AD5546 データシート(HTML) 10 Page - Analog Devices |
|
|
10 / 20 page  AD5546/AD5556 Data Sheet Rev. D | Page 10 of 20 CIRCUIT OPERATION DIGITAL-TO-ANALOG (DAC) CONVERTER SECTION The AD5546/AD5556 are 16-/14-bit multiplying, current out- put, and parallel input DACs. The devices operate from a single 2.7 V to 5.5 V supply and provide both unipolar 0 V to –VREF, or 0 V to +VREF, and bipolar ±VREF output ranges from a –18 V to +18 V reference. In addition to the precision conversion RFB commonly found in current output DACs, there are three addi- tional precision resistors for four-quadrant bipolar applications. The AD5546/AD5556 consist of two groups of precision R-2R ladders, which make up the 12/10 LSBs, respectively. Further- more, the four MSBs are decoded into 15 segments of resistor value 2R. Figure 17 shows the architecture of the 16-bit AD5546. Each of the 16 segments in the R-2R ladder carries an equally weighted current of one-sixteenth of full scale. The feedback resistor, RFB, and four-quadrant resistor, ROFS, have values of 10 kΩ. Each four-quadrant resistor, R1 and R2, equals 5 kΩ. In four-quadrant operation, R1, R2, and an external op amp work together to invert the reference voltage and apply it to the REF input. With ROFS and RFB connected as shown in Figure 2, the output can swing from –VREF to +VREF. The reference voltage inputs exhibit a constant input resistance of 5 kΩ ±20%. The DAC output, IOUT, impedance is code depen- dent. External amplifier choice should take into account the variation of the AD5546/AD5556 output impedance. The feedback resistance in parallel with the DAC ladder resistance dominates output voltage noise. To maintain good analog performance, it is recommended to bypass the power supply with a 0.01 μF to 0.1 μF ceramic or chip capacitor in parallel with a 1 μF tantalum capacitor. Also, to minimize gain error, PCB metal traces between VREF and RFB should match. Every code change of the DAC corresponds to a step function; gain peaking at each output step may occur if the op amp has limited GBP and excessive parasitic capacitance present at the op amp inverting node. A compensation capacitor, therefore, may be needed between the I-V op amp inverting and output nodes to smooth the step transition. Such a compensation capacitor should be found empirically, but a 20 pF capacitor is generally adequate for the compensation. The VDD power is used primarily by the internal logic and to drive the DAC switches. Note that the output precision degrades if the operating voltage falls below the specified voltage. The user should also avoid using switching regulators because device power supply rejection degrades at higher frequencies. 2R 80kΩ R 40kΩ 2R 80kΩ 2R 80kΩ 2R 80kΩ 2R 80kΩ 2R 80kΩ R 40kΩ 2R 80kΩ R 2R 80kΩ R 2R 80kΩ R 2R 80kΩ R 2R 80kΩ 2R 80kΩ R 40kΩ R2 5kΩ R1 5kΩ REF 2R 80kΩ R 40kΩ 2R 80kΩ R 40kΩ 2R 80kΩ R 40kΩ 2R 80kΩ R 40kΩ 2R 80kΩ R 40kΩ 2R 80kΩ RCOM R1 ADDRESS DECODER DAC REGISTER INPUT REGISTER LDAC WR RS RS 4 MSB 15 SEGMENTS 8-BIT R–2R 4-BIT R–2R 16 8 4 LDAC WR D15 D14 D0 RS 10kΩ 10kΩ ROFS RFB IOUT GND RA RB Figure 17. 16-Bit AD5546 Equivalent R-2R DAC Circuit with Digital Section |
同様の部品番号 - AD5546 |
|
同様の説明 - AD5546 |
|
|
|
リンク URL |
| プライバシーポリシー |
| ALLDATASHEET.JP |
| ALLDATASHEETはお客様のビジネスに役立ちますか？ [ DONATE ] |
Alldatasheetは | 広告 | お問い合わせ | プライバシーポリシー | リンク交換 | メーカーリスト All Rights Reserved©Alldatasheet.com |
| Russian : Alldatasheetru.com | Korean : Alldatasheet.co.kr | Spanish : Alldatasheet.es | French : Alldatasheet.fr | Italian : Alldatasheetit.com Portuguese : Alldatasheetpt.com | Polish : Alldatasheet.pl | Vietnamese : Alldatasheet.vn Indian : Alldatasheet.in | Mexican : Alldatasheet.com.mx | British : Alldatasheet.co.uk | New Zealand : Alldatasheet.co.nz |
|
Family Site : ic2ic.com |
icmetro.com |
Japanese ▼
English
Chinese
German
Japanese
Russian
Korean
Spanish
French
Italian
Portuguese
Polish
Vietnamese
Indian
Mexican
British
New Zealand
