 |
Electronic Components Datasheet Search |
|
|
Electronic Components Datasheet Search |
|
SP385AEA Datasheet(PDF) 6 Page - Sipex Corporation |
|
||||||||||||||||||||||||||||||
SP385AEA Datasheet(HTML) 6 Page - Sipex Corporation |
|
|
6 / 9 page  SP385ADS/05 SP385A Line Driver/Receiver © Copyright 2000 Sipex Corporation 6 Charge Pump The charge pump section of the these devices allows the circuit to operate from a single +5V ±10% power supply by generating the required operating voltages internal to the devices. The charge pump consists of two sections — 1) a voltage doubler and 2) a voltage inverter. As shown in Figure 1, an internal oscillator trig- gers the charge accumulation and voltage inver- sion. The voltage doubler momentarily stores a charge on capacitor C 1 equal to Vcc, referenced to ground. During the next transition of the oscillator this charge is boot-strapped to transfer charge to capacitor C 3. The voltage across C3 is now from V cc to V +. In the inverter section (Figure 2), the voltage across C 3 is transferred to C2 forcing a range of 0V to V+ across C 2. Boot-strapping of C2 will then transfer charge to C 4 to genrate V -. One of the significant enhancements over previ- ous products of this type is that the values of the capacitors are no longer critical and have been decreased in size considerably to 0.1 µF. Because the charge pump runs at a higher frequency, the 0.1 µF capacitors are sufficient to transfer and sustain charges to the two transmitters. APPLICATION HINTS Protection From Shorts to ±15V The driver outputs are protected against shorts to ground, other driver outputs, and V+ or V-. If the possibility exists that the outputs could be inadvertently connected to voltages higher than ±15V, then it is recommended that external protection be provided. For protection against voltages exceeding ±15V,twoback-to-backzener diodes connected from each output to ground will clamp the outputs to an acceptable voltage level. Shutdown (ON/OFF) The SP385A has a shut-down/standby mode to conserve power in battery-powered systems. To activate the shutdown mode, which stops the op- eration of the charge pump, a logic “0” is applied to the appropriate control line. The shutdown mode is controlled on the SP385A by a logic “0” on the ON/OFF control line (pin 18 for the SOIC and pin 20 for the SSOP packages); this puts the transmitter outputs in a tri–state mode. Figure 1. Charge Pump Voltage Doubler Figure 2. Charge Pump Voltage Inverter S1 GND V CC + V+ = 2V CC + V CC S2 S3 S4 C1 C3 INTERNAL OSCILLATOR S1 FROM VOLTAGE DOUBLER V+ + V- = -(V+) + S2 S3 S4 C2 C4 INTERNAL OSCILLATOR GND GND |
Similar Part No. - SP385AEA |
|
Similar Description - SP385AEA |
|
|
|
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
