 |
Electronic Components Datasheet Search |
|
|
Electronic Components Datasheet Search |
|
TS6001BIG325TP Datasheet(PDF) 9 Page - Touchstone Semiconductor Inc |
|
||||||||||||||||||||||||||||||
TS6001BIG325TP Datasheet(HTML) 9 Page - Touchstone Semiconductor Inc |
|
|
9 / 12 page  TS6001 TS6001DS r1p0 Page 9 RTFDS improved output current accuracy, ISET should be at least 10 times IQSC. A Negative, Precision Voltage Reference without Precision Resistors When using current-output DACs, it is oftentimes desired that the polarity of the output signal voltage is the same as the external reference voltage. There are two conventional techniques used to accomplish this objective: a) inverting the full-scale DAC output voltage or b) converting a current-output DAC into a voltage-switching DAC. In the first technique, an op amp and pair of precision resistors would be required because the DAC’s output signal voltage requires re-inversion to match the polarity of the external reference voltage. The second technique is a bit more involved and requires converting the current-output DAC into a voltage-switching DAC by driving the DAC’s VREF and IOUT terminals in reverse. Additional components required are two precision resistors, an op amp, and an external voltage reference, typically a 1.25-V reference. If the 1.25-V full-scale output voltage requires scaling to a 2.5-V or a 5-V full scale, then a second op amp and pair of precision resistors would be necessary to perform the amplification. To avoid the need for either re-inversion of the current- switching DAC’s output voltage or amplifying the voltage-swi tching DAC’s output voltage, it would then be desired to apply a negative voltage reference to the original current-switching DAC. In general, any positive voltage reference can be converted into a negative voltage reference using pair of matched resistors and an op amp configured for inverting mode operation. The disadvantage to this approach is that the largest single source of error in the circuit is the relative matching of the resistors used. The circuit illustrated in Figure 5 avoids the need for multiple op amps and well-matched resistors by using an active integrator circuit. In this circuit, the voltage reference’s output is used as the input signal to the integrator. Because of op amp loop action, the integrator adjusts its output voltage to establish the correct relationship between the reference’s OUT and GND terminals (=VREF). In other words, the output voltage polarity of the integrator stage is opposite that of the reference’s output voltage. The 2200pF capacitor at the output of the TS6001 is optional and the resistor in series with the output of the op amp should be empirically determined based on the amplifier choice and whether the amplifier is required to drive a large capacitive load. Rail-to-rail output op amps used for the integrator stage work best in this application; however, these types of op amps require a finite amount of headroom (in the millivolt range) when sinking load current. Therefore, good engineering judgment is always recommended when selecting the most appropriate negative supply for the circuit. How to Use the TS6001 in a High-Input Voltage Floating Current Source By adopting the technique previously shown in Figure 2, the basic floating current source circuit can be adapted to operate at much higher supply voltages beyond the supply voltage rating of the TS6001-2.5 by adding a discrete n-channel JFET. As shown in Figure 6, the JFET acts as a supply voltage regulator since its source voltage will always be 2.5V higher than VSY. The circuit minimizes reference IC self-heating because the JFET and the 2N3904 NPN transistor carry the load current. This circuit can operate up to +35V and is determined by the BVDS breakdown voltage of the external JFET. Figure 4: A Low-power, General-Purpose Current Source. Figure 5: How to Convert a VREF to a –VREF without Precision Resistors. |
Similar Part No. - TS6001BIG325TP |
|
Similar Description - TS6001BIG325TP |
|
|
|
Link URL |
| Privacy Policy |
| ALLDATASHEET.COM |
| Does ALLDATASHEET help your business so far? [ DONATE ] |
About Alldatasheet | Advertisement | Datasheet Upload | Contact us | Privacy Policy | Link Exchange | Manufacturer List 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 |
English ▼
English
Chinese
German
Japanese
Russian
Korean
Spanish
French
Italian
Portuguese
Polish
Vietnamese
Indian
Mexican
British
New Zealand
