5 4 3 2 1 LAN9303M 72QFN Customer Evaluation Board ASSY 6551 Schematic Revision 1.3 D D Design Details Board: Assy 6551 Chip: LAN9303M Board Form Factor: 3.5" x 4" C Circuit Diagrams utilizing SMSC Products Are Included As A Means Of Illustrating Typical Semiconductor Applications: Consequently Complete Information Sufficient For Construction Purposes Is Not Necessarily Given. The Information Has Been Carefully Checked And Is Believed To Be Entirely Reliable. However, No Responsibility Is Assumed For Inaccuracies. Furthermore, Such Information Does Not Convey To The Purchaser Of The Semiconductor Devices Described Any License Under The Patent Rights Of SMSC Or Others. SMSC Reserves The Right To Make Changes At Any Time In Order To Improve Design And Supply The Best Product Possible. Assembly: 72QFN ITEM B C Page(s) Title Page 1 Power 2 LAN9303M 3 MII, Reset, I2C 4 LAN9303M Ethernet Ports 5 B A A Title LAN9303M 3-Port Switch w/ Dual MII/RMII/Turbo MII Size C Date: 5 4 3 2 Engineer Assembly No. R.W. 6551 Thursday, May 14, 2009 1 PCB Rev Schematic Rev A Sheet 1.3 1 of 5 5 4 3 2 1 +5V P1 1 + C3 0.01uF 50V 10% 2 R3 402 1/10W 1% G 2 C4 0.1uF 25V 10% +3.3V C2 22uF 16V 10% 1 1 1 - 4 1x3 2 1/10W 1% 2 3 1 R4 10.0K 2 D 1 POWER 2 R2 100K 1/10W 1% 2 D 2 1 1 S1 SPDT_TINY_TOG 2 POWER SUPPLY R1 33.2K 1/10W 1% 8 7 6 5 D D D D Q1 2 2 - S S S 1 C1 4.7uF 25V 10% 2 2 GND + 3 F1 2A FUSE_SMF GND INT 1 3 3 2 1 1 1 +V JP1 IRF7424 +5V_FUSE JP2 3 LED1 Green LED LED_0805 D 1 1 G 2 S Q2 2N7002 SOT23 NOTE: Populate JP2 (1-2) to disable remote power up but enable switch. Populate JP2 (2-3) to disable turn on circuit and force power on. +3.3V Regulator +3.3V VR1 +5V - 1 + C6 0.1uF 10V 10% C7 22uF 16V 10% + - C8 100uF 10V 10% 2 C 2 C 2 C5 0.1uF 10V 10% R5 1.0K 1/8W 1% DNP 2 1 LT1086-3.3 M_PAKAGE_3 2 1 1 1 2 4 2 Vout Vout#4 1 Vin 1 3 Adj/Gnd JP3 R6 0 Power Supply Filtering LAN9303M +3.3V VDD33A1 +3.3V VDD33A2 1 1 1 1 2 2 2 VDD33BIAS C28 4.7uF 6.3V 20% 0603 1 1 2.0 Amp/0.05 DCR C27 4.7uF 6.3V 20% 0603 DNP C29 0.1uF 16V 10% 2 C26 0.1uF 16V 10% 2 C25 0.1uF 16V 10% B 2 2 2.0 Amp/0.05 DCR 1 1 2 2 1 1 C24 0.1uF 16V 10% +3.3V FB4 2 2 Place 4.7uF by LAN9303M-41 C23 4.7uF 6.3V 20% 0603 2 1 1 C22 0.1uF 16V 10% C19 0.1uF 16V 10% FB3 1 2 2 2 1 1 1 1 C18 0.1uF 16V 10% VDD18PLL VDD18CORE TP2 C21 0.1uF 16V 10% C17 0.1uF 16V 10% VDD18TX TP1 C20 4.7uF 6.3V 20% 0603 C16 0.1uF 16V 10% 1 VDD18CORE C15 4.7uF 6.3V 20% 0603 2 C14 4.7uF 6.3V 20% 0603 DNP C13 0.1uF 16V 10% 2 C12 0.1uF 16V 10% 2 2.0 Amp/0.05 DCR 1 1 2 1 C11 4.7uF 6.3V 20% 0603 DNP 2 2 2 C10 0.1uF 16V 10% 2 C9 0.1uF 16V 10% 2 1 1 2.0 Amp/0.05 DCR 1 2 1 1 B +3.3V FB2 1 FB1 Place 4.7uF by LAN9303M-65 J1 1 J2 2 1 2 A A 1x2 1x2 TP3 MTG1 MTG2 MTG3 MTG4 1 1 1 1 NC NC NC NUM3 Plated Hole .250 Dia. NUM3 Plated Hole .250 Dia. NUM3 Plated Hole .250 Dia. TP4 1 1 NC NUM3 Plated Hole .250 Dia. Title Power Size C Date: 5 4 3 2 Engineer Assembly No. R.W. 6551 Thursday, May 14, 2009 1 PCB Rev Schematic Rev A Sheet 1.3 2 of 5 4 2 1 D 55 +3.3V P0_MODE0 VDD18PLL 65 VDD18PLL VDD18TX2 62 VDD18TX1 8 41 VDD18CORE VDD18CORE 64 VDD33BIAS 66 69 VDD33A2 VDD33A2 7 17 28 40 46 VDD33IO VDD33IO VDD33IO VDD33IO VDD33IO VDD33BIASVDD18TX VDD33A1 VDD33A2 VDD18CORE 58 61 +3.3V D 3 VDD33A1 VDD33A1 5 R7 2 1 +3.3V TEST1 47 TEST1 48 TEST2 U1 4 4 4 4 4 4 C TP6 MDC MDIO 72 1 2 3 4 5 25 P0_IND3 P0_IND2 P0_IND1 P0_IND0 P0_INDV P0_INER P0_DUPLEX 1 4 4 4 4 4 4 TP7 1 13 14 15 16 18 19 35 P1_IND3 P1_IND2 P1_IND1 P1_IND0 P1_INDV P1_INER P1_DUPLEX 4 EE_SDA/SDA 4 EE_SCL/SCL EE_SDA/SDA EE_SCL/SCL 49 50 51 MDC MDIO P0_IND3 P0_IND2 P0_IND1 P0_IND0 P0_INDV P0_INER P0_DUPLEX P1_IND3 P1_IND2 P1_IND1 P1_IND0 P1_INDV P1_INER P1_DUPLEX EE_SDA/SDA EE_SCL/SCL nRST 56 57 59 60 TXN1 TXP1 RXN1 RXP1 5 5 5 5 TXN2 TXP2 RXN2 RXP2 71 70 68 67 TXN2 TXP2 RXN2 RXP2 5 5 5 5 IRQ 52 P0_OUTDV P0_COL P0_CRS P0_INCLK P0_OUTCLK P0_OUTD3/DUPLEX_POL_0 P0_OUTD2/P0_MODE2 P0_OUTD1/P0_MODE1 P0_OUTD0/P0_MODE0 21 23 24 6 22 9 10 11 12 P1_OUTDV P1_COL P1_CRS P1_INCLK P1_OUTCLK P1_OUTD3/DUPLEX_POL_1 P1_OUTD2/P1_MODE2 P1_OUTD1/P1_MODE1 P1_OUTD0/P1_MODE0 42 36 37 20 43 38 39 44 45 EXRES 63 XI 53 XO 54 1 P0_OUTD0/P0_MODE0 2 10.0K 1/10W 1% 10.0K 1/10W 1% R11 R12 2 1 10.0K 1/10W 1% R13 P0_OUTDV P0_COL P0_CRS R18 P0_INCLK_LAN R17 P0_OUTCLK_LAN P0_OUTD3/DUPLEX_POL_0 P0_OUTD2/P0_MODE2 P0_OUTD1/P0_MODE1 P0_OUTD0/P0_MODE0 R25 P0_OUTDV 4 P0_COL 4 P0_CRS 4 P0_INCLK 4 P0_OUTCLK 4 P0_OUTD3/DUPLEX_POL_0 4 P0_OUTD2/P0_MODE2 4 P0_OUTD1/P0_MODE1 4 P0_OUTD0/P0_MODE0 4 10.0K 1/10W 1% 0 0 P1_INCLK P1_OUTCLK P1_OUTDV 4 P1_COL 4 P1_CRS 4 P1_INCLK 4 P1_OUTCLK 4 10.0K 1/10W 1% R19 R20 1 10.0K 1/10W 1% R23 R24 1 10.0K 1/10W 1% R26 R27 1 10.0K 1/10W 1% 1 2 DUPLEX_POL_1 R29 1 P1_OUTD3/DUPLEX_POL_1 2 10.0K 1/10W 1% R30 P1_MODE2 10.0K 1/10W 1% 2 1 P1_MODE1 1 P1_OUTD2/P1_MODE2 2 R28 LAN9303M QFN72_10X10XP5 C 1 P1_OUTD1/P1_MODE1 2 10.0K 1/10W 1% 2 P1_MODE0 1 P1_OUTD0/P1_MODE0 2 10.0K 1/10W 1% 2 P1_OUTD3/DUPLEX_POL_1 4 P1_OUTD2/P1_MODE2 4 P1_OUTD1/P1_MODE1 4 P1_OUTD0/P1_MODE0 4 1 P0_OUTD3/DUPLEX_POL_0 2 10.0K 1/10W 1% 2 DUPLEX_POL_0 R16 1 TP5 1x2 2 12.4K 1 1 P0_OUTD2/P0_MODE2 2 R15 0 0 P1_OUTDV P1_COL P1_CRS P1_INCLK_LAN R21 R22 P1_OUTCLK_LAN P1_OUTD3/DUPLEX_POL_1 P1_OUTD2/P1_MODE2 P1_OUTD1/P1_MODE1 P1_OUTD0/P1_MODE0 1 10.0K 1/10W 1% 2 P0_MODE2 R14 2 IRQ P0_MODE1 1 P0_OUTD1/P0_MODE1 2 10.0K 1/10W 1% 1% 73 4 nRST 27 26 VSS_EPAD 4 MDC 4 MDIO TXN1 TXP1 RXN1 RXP1 LED0/GPIO0/AMDIX1_LED0P 5 LED1/GPIO1/AMDIX2_LED1P 5 LED2/GPIO2/E2PSIZE_LED2P 5 LED3/GPIO3/MNGT0_LED3P 5 LED4/GPIO4/MNGT1_LED4P 5 LED5/GPIO5/PHYADDR_LED5P 5 2 DNP R9 0 34 33 32 31 30 29 1 R8 0 LED0/GPIO0/AMDIX1_LED0P LED1/GPIO1/AMDIX2_LED1P LED2/GPIO2/E2PSIZE_LED2P LED3/GPIO3/MNGT0_LED3P LED4/GPIO4/MNGT1_LED4P LED5/GPIO5/PHYADDR_LED5P LED0/GPIO0/AMDIX1_LED0P LED1/GPIO1/AMDIX2_LED1P LED2/GPIO2/E2PSIZE_LED2P LED3/GPIO3/MNGT0_LED3P LED4/GPIO4/MNGT1_LED4P LED5/GPIO5/PHYADDR_LED5P R10 10.0K 1/10W 1% 1.00M Y1 25.000MHz HC49US 1 2 B C31 30pf 0805 +3.3V 2 MDC 2 R31 1.50K 1/10W 1% 1 C30 30pf 0805 3 B JP4 1 JP5 1x2 MDIO 1 2 1 1 3 R33 10.0K 1/10W 1% 2 1x3 2 R32 2.49K 1/10W 1% S2 P0_MODE0 P0_MODE1 P0_MODE2 DUPLEX_POL_0 P1_MODE0 P1_MODE1 P1_MODE2 DUPLEX_POL_1 1 2 3 4 5 6 7 8 16 15 14 13 12 11 10 9 TDA08H0SK1R A A Title LAN9303M Size C Date: 5 4 3 2 Engineer Assembly No. R.W. 6551 Thursday, May 14, 2009 1 PCB Rev Schematic Rev A Sheet 1.3 3 of 5 5 4 3 2 Port 1 MII Male Connector for External MAC Board 1 Port 0 MII Male Connector for External MAC Board P3 R38 3 P1_INCLK P1_INCLK 1 3 P1_OUTCLK P1_OUTCLK 3 2 3 P1_OUTDV 3 P1_OUTD0/P1_MODE0 3 P1_OUTD1/P1_MODE1 3 P1_OUTD2/P1_MODE2 3 P1_OUTD3/DUPLEX_POL_1 R45 DNP R44 DNP 3 P1_INER R37 0 3 P0_INCLK 3 P0_OUTCLK C33 10uF 16V SMD_B + P0_INCLK 1 P0_OUTCLK 3 2 3 MDC 3 MDIO P0_IND3 P0_IND2 P0_IND1 P0_IND0 P0_INDV 3 P0_INER MDC MDIO 3 P0_OUTDV 3 P0_OUTD0/P0_MODE0 3 P0_OUTD1/P0_MODE1 3 P0_OUTD2/P0_MODE2 3 P0_OUTD3/DUPLEX_POL_0 R42 R43 2 2 AMP - 5174216-2 MII_VERT R48 49.9K 1 R47 49.9K 1 R46 49.9K 1 3 3 3 3 3 +5V Chassis2 Chassis1 Port 1 MII Female Connector for External PHY Board C R53 +5V R55 R52 MDIO MDC P1_INCLK R57 P1_OUTCLK R59 2 P1_COL P1_CRS 0 0 0 MDIO_1_R1 MDC_1_R1 P1_IND3 P1_IND2 P1_IND1 P1_IND0 P1_INDV 0 P1_INCLK_R P1_INER TXER_1 0 OUTCLK_R P1_OUTDV P1_OUTD0/P1_MODE0 P1_OUTD1/P1_MODE1 P1_OUTD2/P1_MODE2 P1_OUTD3/DUPLEX_POL_1 0 P1_COL_R1 0 P1_CRS_R1 R62 R63 DNP R49 49.9K +5V[4] CRS COL TXD3 TXD2 TXD1 TXD0 TX_EN TX_CLK TX_ER RX_ER RX_CLK RX_DV RXD0 RXD1 RXD2 RXD3 MDC MDIO +5V[3] +5V[2] COMMON[18] COMMON[17] COMMON[16] COMMON[15] COMMON[14] COMMON[13] COMMON[12] COMMON[11] COMMON[10] COMMON[9] COMMON[8] COMMON[7] COMMON[6] COMMON[5] COMMON[4] COMMON[3] COMMON[2] COMMON[1] +5V[1] AMP - 174218-2 MII_RA 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 +5V D C32 10uF 16V SMD_B + P2 Port 0 MII Female Connector for External PHY Board FEMALE MII CONN J3 C 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 +5V MDIO MDC R54 R51 P0_INCLK R56 R50 0 0 0 MDIO_0_R1 MDC_0_R1 P0_IND3 P0_IND2 P0_IND1 P0_IND0 P0_INDV 0 P0_INCLK_R1 P0_INER MII_TXER_0 0 P0_OUTCLK_R1 P0_OUTDV P0_OUTD0/P0_MODE0 P0_OUTD1/P0_MODE1 P0_OUTD2/P0_MODE2 P0_OUTD3/DUPLEX_POL_0 0 P0_COL_R1 0 P0_CRS_R1 R58 P0_OUTCLK 2 R65 49.9K 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 20 0 P0_CRS_R2 19 0 P0_COL_R2 18 P0_IND3 17 P0_IND2 16 P0_IND1 15 P0_IND0 14 P0_INDV 13 P0_INCLK_MRACON 12 P0_INER 11 RXER_0 10 P0_OUTCLK 9 P0_OUTDV 8 P0_OUTD0/P0_MODE0 7 P0_OUTD1/P0_MODE1 6 P0_OUTD2/P0_MODE2 5 P0_OUTD3/DUPLEX_POL_04 0 MDC_0_R2 3 0 MDIO_0_R2 2 1 R35 R39 P0_CRS P0_COL 3 P0_CRS 3 P0_COL 2 MDC MDIO 3 MDC 3 MDIO P1_IND3 P1_IND2 P1_IND1 P1_IND0 P1_INDV +5V[2] COMMON[18] COMMON[17] COMMON[16] COMMON[15] COMMON[14] COMMON[13] COMMON[12] COMMON[11] COMMON[10] COMMON[9] COMMON[8] COMMON[7] COMMON[6] COMMON[5] COMMON[4] COMMON[3] COMMON[2] COMMON[1] +5V[1] R60 R61 P0_COL P0_CRS Chassis2 Chassis1 3 3 3 3 3 R36 0 +5V[4] CRS COL TXD3 TXD2 TXD1 TXD0 TX_EN TX_CLK TX_ER RX_ER RX_CLK RX_DV RXD0 RXD1 RXD2 RXD3 MDC MDIO +5V[3] 0 +5V 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 1 D 20 0 P1_CRS_R2 19 0 P1_COL_R2 18 P1_IND3 17 P1_IND2 16 P1_IND1 15 P1_IND0 14 P1_INDV 13 P1_INCLK_MRACON 12 P1_INER 11 RXER_1 10 P1_OUTCLK 9 P1_OUTDV 8 P1_OUTD0/P1_MODE0 7 P1_OUTD1/P1_MODE1 6 P1_OUTD2/P1_MODE2 5 P1_OUTD3/DUPLEX_POL_1 4 0 MDC_1_R2 3 0 MDIO_1_R2 2 1 R41 R40 P1_CRS P1_COL 3 P1_CRS 3 P1_COL R34 0 2 +5V 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 1 1 R64 49.9K 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 FEMALE MII CONN J4 B B +3.3V 1 +3.3V 3 0 1 TP8 TPS3125 SOT23-5 Threshold = 2.64V Delay = 180ms 2 A1 3 A2 WP 7 SDA 5 SCLK 6 1 R70 10.0K R71 10.0K Aardvark I2C Header +3.3V J5 EE_SCL/SCL EE_SDA/SDA JP6 1 3 5 7 EE_SDA EE_SCL 24LC64 SOIC-8 2 4 6 8 EE_SDA/SDA EE_SCL/SCL EE_SDA/SDA 3 EE_SCL/SCL 3 2 R67 10.0K 1/10W 1% 2 8 1 A0 1 1 U2 1 R66 10.0K 1/10W 1% 2 RESET nRST 3 2 1 VCC R72 RESET# 4 MR# 2 VDD 4 GND 2 1/10W 1% 2 S3 1 R73 100 GND 5 U3 I2C Serial EEPROM C34 0.1uF 16V 10% R69 10.0K 1/10W 1% 2 1 2 R68 10.0K 1/10W 1% +3.3V 1 +3.3V C35 0.1uF 16V 10% 2 1 +3.3V 1 3 5 7 9 SCL SDA MISO SCLK CS GND NC/+5V NC/+5V MOSI GND 2 4 6 8 10 Aardvark I2C/ SPI Header HEAD2x5_SHRD 2x4 A A Title Port 0 / Port 1 Quick Switches and MII Connectors Size C Date: 5 4 3 2 Engineer Assembly No. R.W. 6551 Thursday, May 14, 2009 1 PCB Rev Schematic Rev A Sheet 1.3 4 of 5 4 R79 10.0 1/8W 1% GRN LED2_ANODE 2 RJ45 2 2 1 332 1/10W 1% 9 10 T1 Pulse - J0011D01B 1 C R78 49.9 1/8W 1% 1 1 R77 49.9 1/8W 1% 2 R74 LED2_CATHODE 2 R76 49.9 1/8W 1% 1 1 NOTE: Place 49.9 ohm resistors near U1. Place 10 ohm resistor near transformer. 2 R75 49.9 1/8W 1% 2 1 VDD33A1 3 A 5 XMIT D 3 TXP1 3 TXN1 1 TD+ 4 TXCT 4&5 2 TD- 2 75 1 75 D FULL DUPLEX R80 LED1_CATHODE 1 RCV RXCT 7&8 6 RD- 6 7 NC 8 CHS GND 75 LED_0805 2 kV IMPORTANT NOTE: Capacitors C37-C40 are optional and are not present on the LAN9303M CEB. These capacitors are required for operation in an EMI constrained environment. NOTE: Place 49.9 ohm resistors near U1. Place 10 ohm resistor near transformer. R83 T2 Pulse - J0011D01B 9 2 2 2 2 GRN 2 2 LED5_ANODE C38 15pF 50V 5% DNP C39 15pF 50V 5% DNP C40 15pF 50V 5% DNP C 332 1/10W 1% A R88 10.0 1/8W 1% C R87 49.9 1/8W 1% 1 R86 49.9 1/8W 1% 1 R85 49.9 1/8W 1% 1 R84 49.9 1/8W 1% 1 1 C 1 C37 15pF 50V 5% DNP 2 LED5_CATHODE 10 VDD33A2 1 332 1/10W 1% RXP1 RXN1 1 TXP1 TXN1 1 LED0_ANODE 2 2 R82 1 2 LED0_CATHODE 1 12 A C MTG 16 15 MTG GND YEL 14 13 2 R81 0 1210 1000 pF GND C36 0.022uF 50V 10% 3 75 332 1/10W 1% 2 1 3 RXN1 RD+ 5 2 LED1_ANODE 1 LED2 Green LED 3 11 3 RXP1 2 RJ45 XMIT 3 TXP2 3 TXN2 1 TD+ 4 TXCT 4&5 2 TD- 2 75 75 1 FULL DUPLEX R89 LED4_CATHODE 1 RCV IMPORTANT NOTE: Capacitors C42-C45 are optional and are not present on the LAN9303M CEB. These capacitors are required for operation in an EMI constrained environment. A 12 11 C MTG MTG 16 15 13 2 YEL R90 LED3_CATHODE 2 LED3_ANODE 1 B TXP2 TXN2 2 +3.3V +3.3V +3.3V +3.3V B RXP2 RXN2 1 332 1/10W 1% C42 15pF 50V 5% DNP C43 15pF 50V 5% DNP C44 15pF 50V 5% DNP 1 CHS GND LED_0805 2 kV C45 15pF 50V 5% DNP 2 8 6 1000 pF 332 1/10W 1% LED3 Green LED 7&8 1 NC 75 2 LED4_ANODE 1 2 RD- 7 75 1 RXCT 6 2 3 2 5 GND C41 0.022uF 50V 10% RD+ GND 1 3 RXN2 3 14 3 RXP2 +3.3V +3.3V R91 10.0K 1/10W 1% JP10 LED2_ANODE R92 10.0K 1/10W 1% JP11 LED3_ANODE 1 LED1_ANODE 1 1 LED0_ANODE JP9 R93 10.0K 1/10W 1% LED5/GPIO5/PHYADDR_LED5P LED4/GPIO4/MNGT1_LED4P LED0/GPIO0/AMDIX1_LED0P LED1/GPIO1/AMDIX2_LED1P LED2/GPIO2/E2PSIZE_LED2P LED3/GPIO3/MNGT0_LED3P LED4/GPIO4/MNGT1_LED4P LED5/GPIO5/PHYADDR_LED5P JP12 LED4_ANODE LED5_ANODE R94 10.0K 1/10W 1% 1 JP8 LED3/GPIO3/MNGT0_LED3P 1 JP7 LED2/GPIO2/E2PSIZE_LED2P 1 LED1/GPIO1/AMDIX2_LED1P LED0/GPIO0/AMDIX1_LED0P R95 10.0K 1/10W 1% LED0/GPIO0/AMDIX1_LED0P 3 LED1/GPIO1/AMDIX2_LED1P 3 LED2/GPIO2/E2PSIZE_LED2P 3 LED3/GPIO3/MNGT0_LED3P 3 LED4/GPIO4/MNGT1_LED4P 3 LED5/GPIO5/PHYADDR_LED5P 3 R96 10.0K 1/10W 1% LED0_CATHODE JP13 LED1_CATHODE JP14 LED2_CATHODE JP15 LED3_CATHODE JP16 2 2 2 2 2 A 2 A LED4_CATHODE JP17 LED5_CATHODE JP18 Title LED0/GPIO0/AMDIX1_LED0P LED2/GPIO2/E2PSIZE_LED2P LED1/GPIO1/AMDIX2_LED1P LED3/GPIO3/MNGT0_LED3P LED4/GPIO4/MNGT1_LED4P LAN9303M Ethernet Ports LED5/GPIO5/PHYADDR_LED5P Size C Date: 5 4 3 2 Engineer Assembly No. R.W. 6551 Thursday, May 14, 2009 1 PCB Rev Schematic Rev A Sheet 1.3 5 of 5