Os motores de busca de Datasheet de Componentes eletrônicos |
|
DAC7541AJPG4 Folha de dados(PDF) 6 Page - Burr-Brown (TI) |
|
|
DAC7541AJPG4 Folha de dados(HTML) 6 Page - Burr-Brown (TI) |
6 / 10 page 6 ® DAC7541A FIGURE 2. DAC7541A Equivalent Circuit (All inputs LOW). FIGURE 3. DAC7541A Equivalent Circuit (All inputs HIGH). 1/4096 I L 90pF I L 60pF R = 10k Ω R FB I OUT 1 I OUT 2 I REF V REF R ≈ 10kΩ 1/4096 I L 90pF I L 55pF R = 10k Ω R FB I OUT 2 I OUT 1 R ≈ 10kΩ I REF V REF amplifier, board layout, and power supply decoupling will all affect the dynamic performance of the DAC7541A. The use of a compensation capacitor may be required when high- speed operational amplifiers are used. It may be connected across the amplifier’s feedback resistor to provide the nec- essary phase compensation to critically dampen the output. See Figures 4 and 6. APPLICATIONS OP AMP CONSIDERATIONS The input bias current of the op amp flows through the feedback resistor, creating an error voltage at the output of the op amp. This will show up as an offset through all codes of the transfer characteristics. A low bias current op amp such as the OPA606 is recommended. Low offset voltage and VOS drift are also important. The output impedance of the DAC is modulated with the digital code. This impedance change (approximately 10k Ω to 30kΩ) is a change in closed-loop gain to the op amp. The result is that VOS will be multiplied by a factor of one to two depending on the code. This shows up as a linearity error. Offset can be adjusted out using Figure 4. Gain may be adjusted using Figure 5. UNIPOLAR BINARY OPERATION (Two-Quadrant Multiplication) Figure 4 shows the analog circuit connections required for unipolar binary (two-quadrant multiplication) operation. With a DC reference voltage or current (positive or negative polarity) applied at pin 17, the circuit is a unipolar D/A converter. With an AC reference voltage or current, the circuit provides two-quadrant multiplication (digitally con- trolled attenuation). The input/output relationship is shown in Table I. BINARY INPUT ANALOG OUTPUT MSB LSB 1111 1111 1111 –VREF (4095/4096) 1000 0000 0000 –VREF (2048/4096) 0000 0000 0001 –VREF (1/4096) 0000 0000 0000 0V TABLE I. Unipolar Codes. C1 phase compensation (10 to 25pF) in Figure 4 may be required for stability when using high speed amplifiers. C1 is used to cancel the pole formed by the DAC internal feedback resistance and output capacitance at Out1. R 1 in Figure 5 provides full scale trim capability—load the DAC register to 1111 1111 1111, adjust R1 for VOUT = – V REF (4095/4096). Alternatively, full scale can be adjusted by omitting R1 and R2 and trimming the reference voltage magnitude. BIPOLAR FOUR-QUADRANT OPERATION Figure 6 shows the connections for bipolar four-quadrant operation. Offset can be adjusted with the A 1 to A2 summing resistor, with the input code set to 1000 0000 0000. Gain may be adjusted by varying the feedback resistor of A 2. The input/output relationship is shown in Table II. BINARY INPUT ANALOG OUTPUT MSB LSB 1111 1111 1111 +VREF (2047/2048) 1000 0000 0000 0V 0111 1111 1111 –VREF (1/2048) 0000 0000 0000 –VREF (2048/2048) TABLE II. Bipolar Codes. |
Nº de peça semelhante - DAC7541AJPG4 |
|
Descrição semelhante - DAC7541AJPG4 |
|
|
Ligação URL |
Privacy Policy |
ALLDATASHEETPT.COM |
ALLDATASHEET é útil para você? [ DONATE ] |
Sobre Alldatasheet | Publicidade | Contato conosco | Privacy Policy | roca de Link | Lista de Fabricantes 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 |