# # LED Associated Components # # Key In Components File for the HTM Module # -------------------------------------------- # # Original Rev. 3-Feb-2018 # Most Recent Rev. 21-Mar-2018 # # # This Comps file holds the LED Series Resistors # and all other LED associated components for all LEDs. # # - Typically these series resistors are between the LED's # Anode and the Bulk_3V3 supply. # # - Sometimes these resistors are between the LED Anode and # the supply voltage for that LED, e.g. Iso_12V LED. # # - For the individual LEDs (i.e. not part of the RJ45s) # # pin #1 is to the West and is the Cathole # pin #2 is to the East and is the Anode # # # The Reference Designators for the LED series resistors # are 200 greater then the reference designator for the LED, # LE1 uses series resistor R201. # # # # Notes: # # The series resistors for the 0805 size LEDs # driven by the 1V8 3V3 Translator chips are # shown in the following table. Note that the # maximum low output voltage from the translator # is 0.45 Volt. The expected drop across the LED # is shown in the second column. # # Value # Theory Actually # Value Used # --------- --------- # Red ( 3.3V - 1.9V - 0.45V ) / 4 mA = 238 Ohm --> 240 Ohm # Yellow ( 3.3V - 1.9V - 0.45V ) / 4 mA = 238 Ohm --> 240 Ohm # Green ( 3.3V - 2.1V - 0.45V ) / 4 mA = 188 Ohm --> 240 Ohm # Blue ( 5.0V - 3.25V - 0.45V ) / 4 mA = 325 Ohm --> 330 Ohm # # # # So using the 240 Ohm series resistors the current that we # actually expect through the different types of LEDs in the # circuits driven by the translator chips is: # # # Red ( 3.3V - 1.9V - 0.45V ) / 240 Ohm --> 3.96 mA # Yellow ( 3.3V - 1.9V - 0.45V ) / 240 Ohm --> 3.96 mA # Green ( 3.3V - 2.1V - 0.45V ) / 240 Ohm --> 3.13 mA # Blue ( 5.0V - 3.25V - 0.45V ) / 330 Ohm --> 3.94 mA # # # # The series resistors for the yellow and green LEDs driven # directly by the Broadcom Swithes are all shown at 220 Ohm # in their Demo board. Their specification sheet showns a # maximum Low Voltage output of 0.5 V at 8 mA for a 3V3 # output pin. With this specification and 240 Ohm resistors # the yellow and green LEDs will probably flow: # # # Yellow ( 3.3V - 1.9V - 0.50V ) / 240 Ohm --> 3.75 mA # Green ( 3.3V - 2.1V - 0.50V ) / 240 Ohm --> 2.92 mA # # # # So for now we will start with all LED series resistors # having a value of 240 Ohms except for the Blue LEDs # which run from 5 Volts will use a 330 Ohms series resistor. # Once we see the HTM Front Panel in operation we may need # to adjust the brightness of some of the LEDs. # # # The Blue LEDs are: LED4 ATCA Blue driven by IPMC # LED48 ROD pin C3 driven by U552 # LED49 ROD pin C4 driven by U552 # # # # # Board_Location # Ref Part_Number Symbol Geometry X Y Properties #----- ----------- ------ ------------------ -------------- ---------- # # # LED Series Resistors Starting from the Top of the card # with the resistors for the upper block # block of 8 general purpose LEDs. # # These are series resistors between an LED's # Anode and the Bulk_3V3 supply. # R201 Res_240_Ohm_0603 SY_JUNK res_0603 15.00 235.00 1 0 R202 Res_240_Ohm_0603 SY_JUNK res_0603 15.00 226.00 1 0 R203 Res_240_Ohm_0603 SY_JUNK res_0603 15.00 217.00 1 0 R204 Res_240_Ohm_0603 SY_JUNK res_0603 15.00 208.00 1 0 R205 Res_240_Ohm_0603 SY_JUNK res_0603 15.00 199.00 1 0 R206 Res_240_Ohm_0603 SY_JUNK res_0603 15.00 190.00 1 0 R207 Res_240_Ohm_0603 SY_JUNK res_0603 15.00 181.00 1 0 R208 Res_240_Ohm_0603 SY_JUNK res_0603 15.00 172.00 1 0 # # LED Series Resistors Finally the 8 series Resistors for the # 2 Condo RJ-45 connectors. # Each of these RJ45 connectors has 4 LEDs. # # These are series resistors between an LED's # Anode and the Bulk_3V3 supply. # R209 Res_240_Ohm_0603 SY_JUNK res_0603 10.00 117.00 2 90 R210 Res_240_Ohm_0603 SY_JUNK res_0603 12.00 117.00 2 90 R211 Res_240_Ohm_0603 SY_JUNK res_0603 14.00 117.00 2 90 R212 Res_240_Ohm_0603 SY_JUNK res_0603 16.00 117.00 2 90 R213 Res_240_Ohm_0603 SY_JUNK res_0603 10.00 65.00 2 90 R214 Res_240_Ohm_0603 SY_JUNK res_0603 12.00 65.00 2 90 R215 Res_240_Ohm_0603 SY_JUNK res_0603 14.00 65.00 2 90 R216 Res_240_Ohm_0603 SY_JUNK res_0603 16.00 65.00 2 90 # # LED Series Resistors for the ISO_12V Power LED LED17 # # This 3x series resistor is between the # LED's Anode and the ISO_12V supply. # R217 Res_1k_Ohm_0603 SY_JUNK res_0603 15.00 160.00 1 0 R218 Res_1k_Ohm_0603 SY_JUNK res_0603 15.00 163.00 1 180 R219 Res_1k_Ohm_0603 SY_JUNK res_0603 15.00 166.00 1 0 # # LED Translator/Driver for the upper 8 General Purpose LEDs # U201 IC_74AVCH8T245 SY_JUNK tssop_24 33.00 204.00 1 0 C201 Cap_220_nFd_0603 SY_JUNK cap_0603 33.00 198.00 1 180 C202 Cap_220_nFd_0603 SY_JUNK cap_0603 33.00 210.00 1 0 # # LED translator/Driver for the lower 8 RJ45 LEDs. # U202 IC_74AVCH8T245 SY_JUNK tssop_24 33.00 164.00 1 90 C203 Cap_220_nFd_0603 SY_JUNK cap_0603 27.00 164.00 1 90 C204 Cap_220_nFd_0603 SY_JUNK cap_0603 39.00 164.00 1 270