![]() |
Electronic Components Datasheet Search |
|
LTC1540CMS8 Datasheet(PDF) 8 Page - Linear Technology |
|
|
LTC1540CMS8 Datasheet(HTML) 8 Page - Linear Technology |
8 / 12 page ![]() 8 LTC1540 sn1540 1540fas TYPICAL APPLICATIONS 3.3V Output Low Dropout Linear Regulator The LTC1540 can be connected as a micropower (IQ = 5.5µA at VIN = 5V) low dropout linear regulator (Figure 7). When the output is low, Q1 turns on, allowing current to charge output capacitor C1. Local feedback formed by R4, Q1 and Q2 creates a constant-current source from the 5V input to C1. R4, R1 and Q2’s VBE also provide current limiting in the case of an output short-circuit to ground. C2 reduces output ripple, while the R2-R3 feedback voltage divider establishes the output voltage. Auto Power-Off Source Figure 8 shows the circuit for a 30mA power supply that has a timed auto power-off function. The comparator output is the switched power supply output. With a 10mA load, it typically provides a voltage of (VBAT – 0.17V). The whole circuit draws a mere 0.8µA of quiescent current with VBAT = 5V. The three resistor voltage divider programs 50mV of hysteresis for the comparator, and sets the IN – voltage at 200mV. This gives an IN + trip threshold of approximately 150mV The RC time constant determines the maximum power-on time of the OUT pin before power down occurs. This period can be approximated by: t = 4.6RC (seconds) The actual time will vary with both the leakage current of the capacitor and the input current at the IN + pin. Figure 7. 3.3V Output Low Dropout Linear Regulator V + V – 1 C3 2 7 8 R1 47k GND OUT 1540 F07 IN+ IN– HYST REF 3 4 5 6 – + R3 750k 1% R2 430k 1% R4 10Ω Q1 TP0610L VIN = 5V Q2 2N3906 C1 10µF VOUT 3.3V C2 2.2nF LTC1540 V + IN+ OUT 432k VBAT V – 21 7 8 3 GND CR (VBAT – 0.17V) 10mA MOMENTARY SWITCH LTC1540 1540 F08 IN – HYST REF 4 5 6 121k 2M – + Figure 8. Auto Power-Off Switch Operates on 0.8µA Quiescent Current |
Similar Part No. - LTC1540CMS8 |
|
Similar Description - LTC1540CMS8 |
|
|
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 |