 |
Datenblatt-Suchmaschine für elektronische Bauteile |
|
|
Datenblatt-Suchmaschine für elektronische Bauteile |
|
MC34710EWR2 Datenblatt(PDF) 11 Page - Freescale Semiconductor, Inc |
|
||||||||||||||||||||||||||||||
MC34710EWR2 Datenblatt(HTML) 11 Page - Freescale Semiconductor, Inc |
|
|
11 / 18 page  Analog Integrated Circuit Device Data Freescale Semiconductor 11 34710 TYPICAL APPLICATIONS TYPICAL APPLICATIONS Figure 4. Typical Application Diagram The MC34710 provides both a buck converter and an LDO regulator in one IC. Figure 4 above shows a typical application schematic for the MC34710. L1 is the buck converter's inductor. The buck inductor is a key component and must not only present the required reactance, but do so at a DC resistance of less than 20 milliohms in order to preserve the converter's efficiency. Also important to the converter's efficiency is the utilization of a low VF Schottky diode for D1. Note that a 0.1uF capacitor is connected between CT and the reset pins; this prevents any possibility of oscillations occurring on the reset line during transitions by allowing the CT pin to discharge to ground potential via the RST pin, and then charge when RST returns to a logic high. The capacitor between the CP1 and CP2 pins is the charge pump's “bucket capacitor”, and sequentially charges and discharges to pump up the reservoir capacitor connected to the VB pin. Note that the reservoir capacitor's cathode is connected to B+ rather than ground. Also note that the charge pump is intended only to provide gate-drive potential for the buck regulator's internal power MOSFET, and therefore connecting external loads to the VB pin is not recommended. The IC's internal VCORE LDO regulator can provide up to 500mA of current as long as the operating junction temperature is maintained below 105 degrees C. The heat- generating power dissipation of the LDO is primarily a function of the Volt x Amp product across the LINB+ and VCORE pins. Therefore, if the LINB+ voltage is >> than the selected VCORE voltage + 0.8V, it is recommended to use a power resistor in series with the LINB+ input to drop the voltage and dissipate the heat externally from the IC. For example, if the output of the buck regulator (V I/O on the schematic) is used as the input to LINB+, and the mode switches are set such that V I/O = 5V and VCORE = 3.3 , then a series resistance of 1.8 ohms at the LINB+ pin would provide an external voltage drop at 500mA while still leaving the minimum required headroom of 0.8V. Conversely, if the mode switches are set such that V I/O = 3.3V and VCORE = 2.5V, then no series resistance would be required, even at the maximum output current of 500mA. Designing a power supply circuit with the MC34710, like all DC-DC converter ICs, requires special attention not only to component selection, but also to component placement (i.e., printed circuit board layout). The MC34710 has a nominal switching frequency of 200kHz, and therefore pcb traces between the buck converter discrete component pins and the IC should be kept as short and wide as possible to keep the parasitic inductance low. Likewise, keeping these pcb traces LDO 1 2 3 4 13 23 24 25 26 27 28 29 30 31 32 B+ 13- 32V RST MODE0 MODE1 MODE2 GND CT CP1 CP2 VB B+ VSW VFB LINB VCORE SUPERVISORY & SHUTDOWN BUCK REG CHARGE PUMP C1 330 μF R1 1K C1 0.1mF C5 0.1 μF C6 10 μF RSERIES 1.8 330 μF C8 1 2 V I/O VCORE SW1 D1 MBRS130LT3 MC34710 100 μH L1 |
Ähnliche Teilenummer - MC34710EWR2 |
|
Ähnliche Beschreibung - MC34710EWR2 |
|
|
|
Link URL |
| Privatsphäre und Datenschutz |
| ALLDATASHEETDE.COM |
| War ALLDATASHEET hilfreich? [ DONATE ] |
Über Alldatasheet | Werbung | Kontakt | Privatsphäre und Datenschutz | Linktausch | Hersteller 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 |
German ▼
English
Chinese
German
Japanese
Russian
Korean
Spanish
French
Italian
Portuguese
Polish
Vietnamese
Indian
Mexican
British
New Zealand
