Electronic Components Datasheet Search |
|
EL7566 Datasheet(PDF) 10 Page - Intersil Corporation |
|
EL7566 Datasheet(HTML) 10 Page - Intersil Corporation |
10 / 14 page 10 FN7102.7 May 8, 2006 It also allows 100% turn-on of the upper PMOS switch, achieving VO close to VIN. The maximum achievable VO is: Where RL is the DC resistance on the inductor and RDSON1 is the PMOS on-resistance, nominally 30m Ω at room temperature with a temperature coefficient of 0.2m Ω/°C. OUTPUT VOLTAGE SELECTION The output voltage can be as high as the input voltage minus the PMOS and inductor voltage drops (as seen previously in Equation 2). Referring to the Typical Application Circuit on page 2, use R1 and R2 to set the output voltage according to the following formula: Some standard values of R1 and R2 are listed in Table 1. It is important that the series combination of R1 and R2 is large enough as to not draw excessive current from the output. VOLTAGE MARGINING The EL7566 has built-in 5% load stress test (commonly called voltage margining) function. Combinations of TM and SEL set the margins shown in Table 2. When this function is not used, both pins should be connected to SGND, either directly or through a 10k Ω resister. Figure 16 shows this feature. SWITCHING FREQUENCY The regulator has a programmable switching frequency of 200kHz to 1MHz. The switching frequency is generated by a relaxation comparator and adjusted by a capacitor from the OSC pin to GND (COSC). The triangle waveform has 95% duty ratio and runs from 0.2V to 1.2V. Refer to the curve in Figure 6 for the appropriate value of COSC for the desired frequency. If external synchronization is desired, the circuit in Figure 21 can be used. Always choose the converter self-switching frequency 20% lower than the sync frequency to accommodate component variations. Protection Features The EL7566 features a wide range of protective measures to prevent the persistence of damaging system conditions. These features are overvoltage, overcurrent, Power-On- Reset (POR), and Thermal Shutdown protection. OVERVOLTAGE PROTECTION (OVP) The EL7566 monitors the output voltage and will shut down if it exceeds 110% of the set regulation point. This is accomplished by comparing the reference to the FB pin voltage. If an overvoltage condition is met, the controller will turn the high-side switch off, the low-side switch on, and pull PGOOD low. The converter will not latch off and will proceed with a soft-start as soon as the fault condition is cleared. OVERCURRENT PROTECTION (OCP) The current information for PWM ramp generation is also used for overcurrent protection. The measured current is compared against a preset Overcurrent threshold (~7-10A). If the output current exceeds the threshold, the output will shut down by turning off the high-side switch and turning the low-side switch on. This event, like OVP, will not latch the converter off. A soft-start will be initiated when the fault is cleared. POWER-ON RESET (POR) To ensure proper regulator operation, a power-on reset feature monitors the input voltage. When adequate input voltage is achieved (VDD > 2.8V), the converter is allowed to soft-start. However, if VDD falls below 2.5V, the regulator will shut down in the same manner as OVP or OCP. THERMAL PROTECTION AND JUNCTION TEMPERATURE INDICATOR An internal temperature sensor continuously monitors the junction temperature. If the junction temperature exceeds 135°C, the regulator is in a fault condition and will shut down. When the temperature falls back below 110°C, the regulator goes through the soft-start procedure again. TABLE 1. VO (V) R1 (kΩ)R2 (kΩ) 0.8 2 Open 12.49 10 1.2 4.99 10 1.5 10 11.5 1.8 12.7 10.2 2.5 21.5 10 3.3 36 11.5 TABLE 2. CONDITION TM SEL VO Normal 0 X Nominal High Margin 1 1 Nominal + 5% Low Margin 1 0 Nominal - 5% VO VIN RL RDSON1 + () IO × – = VO 0.8 1 R1 R2 ------- + ⎝⎠ ⎜⎟ ⎛⎞ × = EL7566 COSC 100pF EXTERNAL SYNC SOURCE FIGURE 20. EXTERNAL SYNC CIRCUIT EL7566 |
Similar Part No. - EL7566_06 |
|
Similar Description - EL7566_06 |
|
|
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 |