NE8392CA

Philips Semiconductors Product specification Coaxial transceiver interface for Ethernet/Thin Ethernet NE8392C DESCRIPTION The NE8392C Coaxial Transceiver Interface (CTI) is a bipolar coaxial line driver/receiver for Ethernet (10base5) and Thin Ethernet (10base2) local area networks. The CTI is connected between the coaxial cable and the Data Terminal Equipment (DTE) and consists of a receiver, transmitter, receive-mode collision detector, heartbeat generator and jabber timer (see Block Diagram). The transmitter output connects directly to a doubly terminated 50Ω cable, while the receiver output, collision detector output and transmitter input are connected to the DTE through isolation transformers. Isolation between the CTI and the DTE is an IEEE 802.3 requirement that can be met on signal lines by using a set of pulse transformers normally available in a standard 16-pin DIP. Power isolation for the CTI is achieved using DC-to-DC conversion through a power transformer (see Figure 1, Connection Diagram). During transmission the jabber timer is initiated to disable the CTI transmitter in the event of a longer than legal length data packet. Receive-mode collision detection circuitry monitors the signals on the coaxial cable to determine the presence of colliding packets and signals the DTE in the event of a collision. At the end of every transmission the heartbeat generator creates a pseudo collision for a short time to ensure that the collision circuitry is functioning correctly. The heartbeat function can be disabled for repeater applications. The CTI is normally part of a three chip set that implements a complete Ethernet/ Thin Ethernet network interface for a DTE (see Figure 2, Interface Diagram). The other chips are a Serial Network Interface (SNI) and a Network Interface Controller (NIC). The SNI provides Manchester Encoding and Decoding while the NIC handles the media access protocol and buffer management tasks. PIN CONFIGURATION N PACKAGE CD+ CD– RX+ VEE VEE RX– TX+ TX– 1 2 3 4 5 6 7 8 16 CDS 15 TXO 14 RXI 13 VEE 12 RR– 11 RR+ 10 GND 9 HBE A PACKAGE CDS TXO CD+ CD– RX+ N/C 4 V EE 5 V EE 6 V EE 7 V EE 8 V EE 9 V EE 10 V EE 11 12 13 RX– TX+ 14 15 16 17 18 GND GND HBE RR+ TX– 3 2 1 28 27 26 25 24 23 22 21 20 19 V EE V EE V EE V EE V EE V EE RR– RXI FEATURES • Compatible with Ethernet II IEEE 802.3 10base5 and 10base2, and ISO 8802/3 interface specifications SD00283 • 100% drop-in compatible with industry standard 8392 sockets • Integrates all transceiver electronics except signal and power isolation • On-chip precision voltage reference for receive mode collision detection • Only one external resistor required for setting coaxial signaling current • Jabber timer function integrated on chip • Heartbeat generator can be externally disabled for operation as IEEE 802.3 compatible repeaters • Squelch circuitry on all signal inputs rejects noise • Full ESD protection • Standard 16-pin DIP and 28-pin PLCC packages • Power-on reset prevents glitches on coaxial cable during power up. • Also available in advanced low-power BiCMOS technology. (See selection chart and data sheets for the NE83C92, NE83Q92 or NE83Q93 for appropriate optimal usages) ORDERING INFORMATION DESCRIPTION 16-Pin Plastic Dual In-Line Package (DIP) 28-Pin Plastic Lead Chip Carrier (PLCC) TEMPERATURE RANGE 0 to +70°C 0 to +70°C ORDER CODE NE8392CN NE8392CA DWG # SOT28-4 SOT261-3 1995 May 1 1 853-1693 15180 Philips Semiconductors Product specification Coaxial transceiver interface for Ethernet/Thin Ethernet NE8392C PIN DESCRIPTIONS PIN NO. N PKG 1 2 3 6 7 8 9 11 12 14 15 PIN NO. PLCC 2 3 4 12 13 14 15 18 19 26 28 SYMBOL CD+ CD– RX+ RX– TX+ TX– HBE RR+ RR– RXI TXO DESCRIPTION Collision Outputs. Balanced differential line driver outputs which send a 10MHz oscillation signal to the DTE in the event of a collision, jabber interrupt or heartbeat test. Receiver Outputs. Balanced differential line driver outputs which send the received signal to the DTE. Transmitter Inputs. Balanced differential line receiver inputs which accept the transmission signal from the DTE and apply it to the coaxial cable at TXO once it meets Tx squelch threshold. Heartbeat Enable. The heartbeat function is disabled when this pin is connected to VEE and enabled when connected to GND or left floating. External Resistor. A 1kΩ (1%) resistor connected between these pins establishes the signaling current at TXO. RR– is internally connected to VEE. Receiver Input. This pin is connected directly to the coaxial cable. Received signals are equalized, amplified, and sent to the DTE through the RX+ pins once it meets Rx squelch threshold. Transmitter Output. This pin is connected directly (Thin Ethernet) or through an external isolating diode (Ethernet) to the coaxial cable. Collision Detect Sense. Ground sense connection for the collision detection circuitry. This pin should be directly connected to the coaxial cable shield to prevent ground drops affecting the collision threshold voltage. Positive Supply Pin. Negative supply pins. These pins also serve as a low thermal resistance path for extracting heat from the die. They should, therefore, be connected to a large metal area on the PC board. 16 1 16 17 5 to 11 20 to 25 CDS 10 4 5 13 GND VEE NOTE: 1. The IEEE 802.3 name for CD is CI; for RX is DI; for TX is DO. ABSOLUTE MAXIMUM RATINGS SYMBOL VEE VIN TSTG TSOLD TJ θJA Supply voltage1 Voltage at any input1 PARAMETER RATING –12 0 to –12 –65 to +150 +300 +130 60 UNIT V V Storage temperature range Lead soldering temperature (10sec.) Recommended max junction temperature2 °C °C °C °C/W Thermal impedance (N and A packages) NOTE: 1. 100% measured in production. 2. The junction temperature is calculated from the following expression: TJ = TA + θJA [VEE (0.08 + n x 0.05/100) + 8(VEE –2) / R] where TA = Ambient temperature in °C. θJA = Thermal resistance of package. VEE = Normal operating supply voltage in volts. n = Percentage transmitter duty cycle. R = Pull down resistors on the RX and CD pins in Ω. The N package is specially designed to have a low θJA by directly connecting the four center Pins 4, 5, 12, and 13 to the die attachment area. These four pins then provide a conductive heat flow path from the die to the PCB where they should be soldered to a large area VEE track. For the A package, Pins 5 to 11 and 19 to 25 should similarly be soldered to a large area VEE and rack. 1995 May 1 2 Philips Semiconductors Product specification Coaxial transceiver interface for Ethernet/Thin Ethernet NE8392C BLOCK DIAGRAM COAX CABLE DTE INTERFACE RXI BUFFER RECEIVER EQUALIZER LINE DRIVER RECEIVE PAIR (RX+, RX–) 4–POLE BESSEL LOW PASS FILTER RECEIVER AC–DC SQUELCH TRANSMIT PAIR (TX+, TX–) TXO CDS SENSE BUFFER TRANSMITTER TRANSMITTER SQUELCH HEARTBEAT ENABLE COLLISION COMPARATOR & HEARTBEAT GENERATOR 10MHz OSC JABBER TIMER LINE DRIVER COLLISION PAIR (CD+, CD–) SD00274 1995 May 1 3 Philips Semiconductors Product specification Coaxial transceiver interface for Ethernet/Thin Ethernet NE8392C ELECTRICAL CHARACTERISTICS VEE = –9V +5%; TA = 0°C to +70°C unless otherwise specified1,2. SYMBOL VPOR IEE IRXI ICDS VIH VIL IIH IIL ITDC ITAC ITX10 VTCOM VCD VOD VOB VOC VRS VTS RRXI CRXI RTXO PARAMETER Power–on reset voltage. Transmitter disabled for |VEE| < |VPOR| Supply current non–transmitting Supply current transmitting Receive input bias current Cable sense input bias current HBE input HIGH voltage HBE input LOW voltage HBE input HIGH current HBE input LOW current Transmit output DC current level3 No external isolation LIMITS TEST CONDITIONS MIN TYP –6.5 –80 –125 VRXI = 0V VCDS = 0V VEE +1.4 VEE +0.4 VHBE = 0V VHBE = VEE –37 ±28 VTXO = –10V –250 250 –500 –41 500 –1000 –45 ±ITDC +250 –3.7 Measured by applying DC voltage at RXI –1450 ±600 –1530 –1580 ±1200 +40 –1.5 VRXI average DC (VTX+ – VTX–) peak –130 –175 100 2 10 –2 –250 –225 –2.5 –370 –300 –2 +2 –130 –180 +25 +6 mA µA µA V V µA µA mA mA µA V mV mV mV V mV mV kΩ pF kΩ MAX UNIT V Transmit output AC current level3 Transmit current Transmitter output voltage Collision threshold5 Differential output voltage – non idle at RX+ and CD+6 Differential output voltage imbalance – idle at RX+ and CD+7 Output common mode voltage at RX± and CD± Receiver squelch threshold Transmitter squelch threshold Shunt resistance at RXI non–transmitting Input capacitance at RXI Shunt resistance at TXO transmitting compliance4 NOTES: 1. Currents flowing into device pins are positive. All voltages are referenced to ground unless otherwise specified. For ease of interpretation, the parameter limit that appears in the MAX column is the largest value of the parameter, irrespective of sign. Similarly, the value in the MIN column is the smallest value of the parameter, irrespective of sign. 2. All typicals are for VEE = –9V and TA = 27°C. 3. ITDC is measured as (VMAX + VMIN)/(2 x 25) where VMAX and VMIN are the max and min voltages at TXO with a 25Ω load between TXO and GND. ITAC is measured as (VMAX – VMIN)/(2 x 25). 4. The TXO pin shall continue to sink at least ITDC min when the idle (no signal) voltage on this pin is –3.7V. 5. Collision threshold for an AC signal is within 10% of VCD. 6. Measured on secondary side of isolation transformer (see Connection Diagram, Figure 1). The transformer has a 1:1 turns ratio with an inductance between 30 and 100µH at 5MHz. 7. Measured as the voltage difference between the RX pins or the CD pins with the transformer removed. 1995 May 1 4 Philips Semiconductors Product specification Coaxial transceiver interface for Ethernet/Thin Ethernet NE8392C TIMING CHARACTERISTICS VEE = –9V +5%; TA = 0 to 70°C, unless otherwise specified1. No external isolation diode on TXO. SYMBOL PARAMETER Receiver start up delay RXI to RX± (Figure 3) First received bit on RX± First validly timed bit on RX± Receiver prop. delay RXI to RX± Differential output rise time on RX± and CD±2,3 Differential output fall time on RX± and CD±2,3 Differential output settling time on RX± and CD± to VOB = 40mV2 (see Figure 4) Receiver and cable total jitter Receiver high to idle time Rise and fall time matching on RX± and CD± Transmitter start–up delay TX± to TXO (Figure 5) tTST First transmitted bit on TXO First validly timed bit tTD tTR tTF tTM tTS tTON tTOFF tCON tCOFF tCHI fCD tCP tHON tHW tJA tJR Transmitter prop delay TX± to TXO (see Figure 5) Transmitter rise time 10% to 90% (see Figure 5) Transmitter fall time 10% to 90% (see Figure 5) tTF – tTR mismatch Transmitter added skew4 Transmitter turn on pulse width (see Figure 5) Transmitter turn off pulse width (see Figure 5) Collision turn on delay (see Figure 6) Collision turn off delay (see Figure 6) Collision high to idle time (see Figure 6) Collision frequency (see Figure 6) Collision signal pulse width (see Figure 6) Heartbeat turn on delay (see Figure 7) Heartbeat test duration (see Figure 7) Jabber activation delay measured from TX± to CD± (see Figure 8) Jabber reset delay measured from TX± to CD± (see Figure 8) VTX± = 1V peak VTX± = 1V peak 0V to –2V step at RXI –2V to 0V step at RXI Measured to +210mV 150 8.0 35 0.6 0.5 20 250 10 10 150 250 VTX± = 1V peak 35 25 25 ±2 ±2 40 340 13 16 850 12.5 70 1.6 1.5 60 750 Measured to +210mV tRF – tRR VTX± = –1V peak 1 2 tTST + 2 50 ns ns ns ns ns ns ns bits bits ns MHz ns µs µs ms ms 150 0.4 VRXI = –2V peak 35 5 5 1 ±3 850 TEST CONDITIONS VRXI = –2V peak LIMITS MIN TYP MAX 5 tRON +2 50 ns ns ns µs ns ns ns UNIT tRON tRD tRR tRF tOS tRJ tRHI tRM bits bits NOTES: 1. All typicals are for VEE = –9V and TA = 27°C. 2. Measured on secondary side of isolation transformer (see Figure 1, Connection Diagram). The transformer has a 1:1 turn ratio with an inductance between 30 and 100µH at 5MHz. 3. The rise and fall times are measured as the time required for the differential voltage to change from –225mV to +225mV, or +225mV to –225mV, respectively. 4. Difference in propagation delay between rising and falling edges at TXO. FUNCTIONAL DESCRIPTION The NE8392C contains four main functional blocks (see Block Diagram). These are: a. The receiver which takes data from the coaxial cable and sends it to the DTE. b. The transmitter which receives data from the DTE and sends it onto the coaxial cable. c. The collision detection and heartbeat generation circuitry which indicates to the DTE any collision on the coaxial cable and tests 1995 May 1 5 for collision circuitry functionality at the end of every transmission. d. The jabber timer which disables the transmitter in the event of a longer than legal length data packet. Receiver Functions The receiver consists of an input buffer, a cable equalizer, a 4-pole Bessel low pass filter, a squelch circuit and a differential line driver. The buffer provides high input resistance and low input capacitance to minimize loading and reflections on the coaxial cable. Philips Semiconductors Product specification Coaxial transceiver interface for Ethernet/Thin Ethernet NE8392C The equalizer is a high pass filter that compensates for the low pass effect of the coaxial cable and results in a flatband response over all signal frequencies to minimize signal distortion. The 4-pole Bessel low pass filter extracts the average DC voltage level on the coaxial cable for use by the receiver squelch and collision detection circuits. The receiver squelch circuit prevents noise on the coaxial cable from falsely triggering the receiver in the absence of a true signal. At the beginning of a packet, the receiver turns on when the DC level from the low pass filter is lower than the DC squelch threshold. For normal signal levels this will take less than 500ns, or 5 bits. However, at the end of a packet, a fast receiver turn off is needed to reject both dribble bits on the coaxial cable and spurious responses due to settling of the on-chip bandpass filter. This is accomplished by an AC timing circuit that disables the receiver if the signal level on the coaxial cable remains high for typically 250ns and only enables the receiver again after approximately 1µs. Figures 3 and 4 illustrate receiver timing. The differential line driver provides typically ±900mV signals to the DTE with less than 7ns rise and fall times. When in idle state (no received signal) its outputs provide