Electronic Components Datasheet Search |
|
ICL7660AIBAZA-T Datasheet(PDF) 7 Page - Intersil Corporation |
|
ICL7660AIBAZA-T Datasheet(HTML) 7 Page - Intersil Corporation |
7 / 12 page 7 FN3072.7 October 10, 2005 The voltage regulator portion of the ICL7660 and ICL7660A is an integral part of the anti-latchup circuitry, however its inherent voltage drop can degrade operation at low voltages. Therefore, to improve low voltage operation the “LV” pin should be connected to GROUND, disabling the regulator. For supply voltages greater than 3.5V the LV terminal must be left open to insure latchup proof operation, and prevent device damage. Theoretical Power Efficiency Considerations In theory a voltage converter can approach 100% efficiency if certain conditions are met. 1. The driver circuitry consumes minimal power. 2. The output switches have extremely low ON resistance and virtually no offset. 3. The impedances of the pump and reservoir capacitors are negligible at the pump frequency. The ICL7660 and ICL7660A approach these conditions for negative voltage conversion if large values of C1 and C2 are used. ENERGY IS LOST ONLY IN THE TRANSFER OF CHARGE BETWEEN CAPACITORS IF A CHANGE IN VOLTAGE OCCURS. The energy lost is defined by: E = 1/2 C1 (V12 - V22) where V1 and V2 are the voltages on C1 during the pump and transfer cycles. If the impedances of C1 and C2 are relatively high at the pump frequency (refer to Figure 12) compared to the value of RL, there will be a substantial difference in the voltages V1 and V2. Therefore it is not only desirable to make C2 as large as possible to eliminate output voltage ripple, but also to employ a correspondingly large value for C1 in order to achieve maximum efficiency of operation. Do’s And Don’ts 1. Do not exceed maximum supply voltages. 2. Do not connect LV terminal to GROUND for supply voltages greater than 3.5V. 3. Do not short circuit the output to V+ supply for supply voltages above 5.5V for extended periods, however, transient conditions including start-up are okay. 4. When using polarized capacitors, the + terminal of C1 must be connected to pin 2 of the ICL7660 and ICL7660A and the + terminal of C2 must be connected to GROUND. 5. If the voltage supply driving the ICL7660 and ICL7660A has a large source impedance (25 Ω - 30Ω), then a 2.2µF capacitor from pin 8 to ground may be required to limit rate of rise of input voltage to less than 2V/ µs. 6. User should insure that the output (pin 5) does not go more positive than GND (pin 3). Device latch up will occur under these conditions. A 1N914 or similar diode placed in parallel with C2 will prevent the device from latching up under these conditions. (Anode pin 5, Cathode pin 3). VOUT = -VIN C2 VIN C1 S3 S4 S1 S2 8 3 2 5 3 7 FIGURE 12. IDEALIZED NEGATIVE VOLTAGE CONVERTER FIGURE 13A. CONFIGURATION FIGURE 13B. THEVENIN EQUIVALENT FIGURE 13. SIMPLE NEGATIVE CONVERTER 1 2 3 4 8 7 6 5 + - 10 µF ICL7660 VOUT = -V+ V+ + - 10 µF ICL7660A V+ + - RO VOUT ICL7660, ICL7660A |
Similar Part No. - ICL7660AIBAZA-T |
|
Similar Description - ICL7660AIBAZA-T |
|
|
Link URL |
Privacy Policy |
ALLDATASHEET.NET |
Does ALLDATASHEET help your business so far? [ DONATE ] |
About Alldatasheet | Advertisement | 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 |