 |
Electronic Components Datasheet Search |
|
|
Electronic Components Datasheet Search |
|
OPA547FKTWT Datasheet(PDF) 10 Page - Burr-Brown (TI) |
|
|
||||||||||||||||||||||||||||||
OPA547FKTWT Datasheet(HTML) 10 Page - Burr-Brown (TI) |
|
|
10 / 18 page  OPA547 10 SBOS056F www.ti.com THERMAL PROTECTION The OPA547 has thermal shutdown that protects the ampli- fier from damage. Activation of the thermal shutdown circuit during normal operation is an indication of excessive power dissipation or an inadequate heat sink. Depending on load and signal conditions, the thermal protection circuit may cycle on and off. This limits the dissipation of the amplifier but may have an undesirable effect on the load. The thermal protection activates at a junction temperature of approximately 160 °C. However, for reliable operation, junc- tion temperature should be limited to 150 °C. To estimate the margin of safety in a complete design (including heat sink), increase the ambient temperature until the thermal protection is activated. Use worst-case load and signal conditions. For good reliability, the thermal protection should trigger more than 35 °C above the maximum expected ambient condition of the application. This produces a junction temperature of 125 °C at the maximum expected ambient condition. ENABLE/STATUS (E/S) PIN The Enable/Status pin provides two functions: forcing this pin low disables the output stage, or E/S can be monitored to determine if the OPA547 is in thermal shutdown. One or both of these functions can be utilized on the same device using single or dual supplies. For normal operation (output en- abled), the E/S pin can be left open or pulled high (at least +2.4V above the negative rail). Output Disable A unique feature of the OPA547 is its output disable capabil- ity. This function not only conserves power during idle peri- ods (quiescent current drops to approximately 4mA), but also allows multiplexing in low frequency (f<10kHz), multichannel applications. Signals that are greater than 10kHz may cause leakage current to increase in devices that are shutdown. Figure 15 shows the two OPA547s in a switched amplifier configuration. The on/off state of the two amplifiers is con- trolled by the voltage on the E/S pin. To disable the output, the E/S pin is pulled low, no greater than 0.8V above the negative rail. Typically the output is shutdown in 1 µs. Figure 5 provides an example of how to implement this function using a single supply. Figure 6 gives a circuit for dual- supply applications. To return the output to an enabled state, the E/S pin should be disconnected (open) or pulled to at least (V–) + 2.4V. It should be noted that pulling the E/S pin high (output enabled) does not disable internal thermal shutdown. OPA547 V+ E/S V– NOTE: (1) Optional—may be required to limit leakage current of optocoupler at high temperatures. (1) 6 1 1 4N38 Optocoupler 5 4 HCT or TTL In 5V FIGURE 6. Output Disable with Dual Supplies. Thermal Shutdown Status Internal thermal shutdown circuitry shuts down the output when the die temperature reaches approximately 160 °C, resetting when the die has cooled to 140 °C. The E/S pin can be monitored to determine if shutdown has occurred. During normal operation the voltage on the E/S pin is typically 3.5V above the negative rail. Once shutdown has occurred this voltage drops to approximately 350mV above the negative rail. Figure 7 gives an example of monitoring shutdown in a single-supply application. Figure 8 provides a circuit for dual supplies. External logic circuitry or an LED could be used to indicate if the output has been thermally shutdown, see Figure 13. FIGURE 7. Thermal Shutdown Status with a Single Supply. FIGURE 8. Thermal Shutdown Status with Dual Supplies. FIGURE 5. Output Disable with a Single Supply. OPA547 V+ E/S HCT OR TTL 2.49k Ω Zetex ZVN3310 5V V– OPA547 V+ E/S V– 1k Ω 5V 22k Ω 470 Ω 2N3906 Zetex ZVN3310 OPA547 V+ E/S V– CMOS or TTL |
Similar Part No. - OPA547FKTWT |
|
Similar Description - OPA547FKTWT |
|
|
|
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
