Moteur de recherche de fiches techniques de composants électroniques |
|
MIC2561 Fiches technique(PDF) 7 Page - Micrel Semiconductor |
|
MIC2561 Fiches technique(HTML) 7 Page - Micrel Semiconductor |
7 / 8 page MIC2561 Micrel 2-36 1997 However, many cost sensitive designs (especially notebook/ palmtop computers) connect VPP1 to VPP2 and the MIC2557 is not required. This circuit is shown in Figure 4. When a memory card is initially inserted, it should receive V CC — either 3.3V ± 0.3V or 5.0V ±5%. The initial voltage is determined by a combination of mechanical socket “keys” and voltage sense pins. The card sends a handshaking data stream to the controller, which then determines whether or not this card requires V PP and if the card is designed for dual V CC . If the card is compatible with and desires a different V CC level, the controller commands this change by disabling V CC , waiting at least 100ms, and then re-enabling the other V CC voltage. If no card is inserted or the system is in sleep mode, the controller outputs a (VCC3 IN, VCC5 IN) = (0,0) to the MIC2561, which shuts down VCC. This also places the switch into a high impedance output shutdown (sleep) mode, where current consumption drops to nearly zero, with only tiny CMOS leakage currents flowing. During Flash memory programming with standard (+12V) Flash memories, the PCMCIA controller outputs a (1,0) to the EN0, EN1 control pins of the MIC2561, which connects VPP IN to VPP OUT. The low ON resistance of the MIC2561 switches allow using small bypass capacitors (in some cases, none at all) on the VCC OUT and VPP OUT pins, with the main filtering action performed by a large filter capacitor on the input supply voltage to VPP IN (usually the main power supply filter capacitor is sufficient). The VPP OUT transition from VCC to 12.0V typically takes 15µs. After programming is completed, the controller outputs a (EN1, EN0) = (0,1) to the MIC2561, which then reduces VPP OUT to the VCC level for read verification. Break-before-make switching action re- duces switching transients and lowers maximum current spikes through the switch from the output capacitor. The flag comparator prevents having high voltage on the VPP OUT capacitor from contaminating the VCC inputs, by disabling the low voltage VPP switches until VPP OUT drops below the VCC level selected. The lockout delay time varies with the load current and the capacitor on VPP OUT. With a 0.1µF capacitor and nominal IPP OUT, the delay is approximately 250µs. Internal drive and bias voltage is derived from VPP IN. Internal device control logic is powered from VCC3 IN. Input logic threshold voltages are compatible with common PCMCIA controllers using either 3.3V or 5V supplies. No pull-up resistors are required at the control inputs of the MIC2561. Output Current and Protection MIC2561 output switches are capable of more current than needed in PCMCIA applications and meet or exceed all PCMCIA specifications. For system and card protection, output currents are internally limited. For full system protec- tion, long term (millisecond or longer) output short circuits invoke overtemperature shutdown, protecting the MIC2561, the system power supplies, the card socket pins, and the memory card. The MIC2561 overtemperature shutdown oc- curs at a die temperature of 110 °C. Suspend Mode An additional feature in the MIC2561 is a pseudo power-down mode, Suspend Mode, which allows operation without a V PP IN supply. In Suspend Mode, the MIC2561 supplies 3.3V to V CC OUT whenever a V CC output of 3.3V is enabled by the PCMCIA controller. This mode allows the system designer the ability to turn OFF the V PP supply generator to save power when it is not specifically required. The PCMCIA card receives V CC at reduced capacity during Suspend Mode, as the switch resistance rises to approximately 4.5 Ω. High Current V CC Operation Without a +12V Supply Figure 5 shows the MIC2561 with V CC switch bias provided by a simple charge pump. This enables the system designer to achieve full V CC performance without a +12V supply, which is often helpful in battery powered systems that only provide +12V when it is needed. These on-demand +12V System Power Supply PCMCIA Card Slot Controller MIC2561 PCMCIA Card Slot 5V 3.3V 12V EN0 EN1 VPP1 VCC VPPIN VCC5IN VCC3IN VCC5_EN VCC3_EN VPP2 Figure 4. MIC2561 Typical PCMCIA memory card application with dual V CC (5.0V or 3.3V). Note that VPP1 and VPP2 are driven together. |
Numéro de pièce similaire - MIC2561 |
|
Description similaire - MIC2561 |
|
|
Lien URL |
Politique de confidentialité |
ALLDATASHEET.FR |
ALLDATASHEET vous a-t-il été utile ? [ DONATE ] |
À propos de Alldatasheet | Publicité | Contactez-nous | Politique de confidentialité | Echange de liens | Fabricants 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 |