Electronic Components Datasheet Search |
|
SMH4803DHN Datasheet(PDF) 8 Page - Summit Microelectronics, Inc. |
|
SMH4803DHN Datasheet(HTML) 8 Page - Summit Microelectronics, Inc. |
8 / 22 page 8 SMH4803 2041 8.4 6/15/00 SUMMIT MICROELECTRONICS SMH4803 Pin Descripiton PIN NAME (Pin #) Drain Sense (1) The Drain Sense input monitors the voltage at the drain of the external power MOSFET switch with respect to VSS. When the MOSFET is turned on, the Drain Sense input will be driven low and will be used as one of the enable conditions for the PG outputs. This will prevent any premature activation of the PG outputs. Vgate (2) The Vgate output activates an external power MOSFET switch. It is a constant current source (100µA typical) allowing easy programming of the MOSFET turn on slew rate. EN/TS (3) The Enable/Temperature Sense input is the master en- able input. When EN/TS is LOW, Vgate, and the PG outputs are off. As the name suggests, the EN/TS input may be used as a master enable by a host system or alternatively for circuit over-temperature protection using an external thermistor. PD1# and PD2# (4 & 5) The pin detect pins are active LOW inputs that are use to prevent any power sequence before the add-in card is properly seated. Both inputs must be at VSS before either Vgate or the PG outputs can be enabled. In applications where multi-length connector pins are use, the PD inputs should be tied to the short pins. On the mating connector side the pins opposite should be tied directly to VSS. Alternatively, either one or both of the PD inputs can be tied to card injector handle switches, insur- ing no power sequencing will occur until the card is properly seated. CBFault# (6) CBFault# is an open drain active low output, indicating the circuit breaker status. When an over current condition is detected CBFault# is driven low. CBReset# (7) CBReset# is the circuit breaker reset input. It can be actively controlled to reset a fault condition or it can be tied high or low to allow either timed restarts (duty cycle mode) or “latch-off” the Vgate output. Refer to the Circuit Breaker Operation and the associated timing diagrams for de- tailed characteristics. CBMode (8) The CBMode input selects one of two circuit breaker operational modes. When tied to VSS all fault conditions must be cleared by toggling the CBReset# input low then high. When CBMode is tied to 5V the circuit breaker will be placed in the self-restart or cycling mode. The state of CBReset# input will control the operation of the restart. If CBReset# is tied to 5V the Vgate output will automatically restart after tCYC has elapsed. If the fault condition still exists, the circuit breaker will trip once again. The cycling will continue until the fault clears or the circuit board is replaced. Alternatively the CBReset# input can be ac- tively driven to VSS. If a fault occurs the Vgate and PG outputs will not be turned on again for tCYC after the CBReset# input is driven high. CBSense (9) The circuit breaker sense input is used to detect overcurrent conditions in the load connected to the power MOSFET. A low value sense resistor (RS) is tied in series with the MOSFET switch; one end tied to VSS and the other to the switch and the CBSense input. A voltage drop of greater than 50mV (for greater than tCBD) across the resistor will result in the circuit breaker tripping. A pro- grammable “quick-trip” sense point is also available. If the CBSense input transitions above the threshold, the circuit breaker will immediately trip. VSS (10) VSS is connected to the negative side of the supply. UV and OV (11 & 12) The under-voltage (11) and over-voltage (12) input pins monitor the supply voltage for the SMH4803 and the downstream circuits. Both inputs have a 2.5V threshold on their respective comparators. If UV is less than 2.5V or if OV is greater than 2.5V, Vgate will be disabled. 5.0V (13) 5.0V is a precision 5 volt output reference voltage tha may be use to expand the logic-input funtions on the SMH4803. The reference output is with respect to VSS. 2.5V (14) 2.5V is a precision 2.5 volt output reference voltage tha may be use to expand the logic-input funtions on the SMH4803. The reference output is with respect to VSS. ENPGB (15) The ENPGB input may be used to independently switch off the PG3# output. When ENPGB is pulled low, the PG3# output is immediately placed in a high impedance state. If PG2# is active and ENPGB is driven high, then the PG3# output will immediately be driven low. |
Similar Part No. - SMH4803DHN |
|
Similar Description - SMH4803DHN |
|
|
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 |