Echelon Series 6000 Chip databook - Manual (Page 67)

Name Value Description
C1, C2 56 pF, 50 V Common-mode noise immunity
capacitors (for EN61000-4-6 Level 3)
C3, C4 100 pF, 5% Optional center-tap capacitors
C5, C6 22 μF, ≥50 V, polar DC blocking capacitors
D1, D2 BAV99 ESD transient clamping diodes
D3, D4, D5, D6
BAV99, 1N4148-equivalent
1N4934, 1N4935, FR1D,
RS1D, RS1DB
Differential network clamping diodes:
For up to 2 kV Surge Protection
For up to 6 kV Surge Protection
In Figure 20, diodes D1 and D2 are ESD transient clamping diodes. Capacitors C1 and C2
provide common-mode noise immunity for compliance with EN61000-4-6 Level 3. Capacitors
C5 and C6 are used to provide DC voltage isolation for the FT 6000 Smart Transceiver when
it is used on a link power network and to protect it in the event of a DC power fault on the
network wires. The capacitors are required to meet L ON M ARK interoperability guidelines for
the TP/FT-10 channel. These capacitors are not needed for devices that will be connected
exclusively to non-link power networks and do not require protection against DC faults. Two
polar capacitors are used to protect against the application of a DC voltage of either polarity,
while providing a total capacitance of 11 μF. Alternatively, a single non-polar capacitor of 10
μF can be used in either of the two legs that connect to the network. The initial tolerance of
the capacitor should be ±20% or less, and degradation due to aging and temperature effects
should not exceed 20% of the initial minimum value.
In some cases, adding capacitors (C3 and C4) between the center tap pins and earth ground
can reduce EMI emissions.
Note that Series 3100 FT Smart Transceivers had a single COMM_ACTIVE pin (equivalent
to the CP2 pin for a Series 3100 Neuron Chip) that you could connect to a special
COMM_ACTIVE LED circuit to drive a pair of LEDs to display network activity. FT 6000
Smart Transceivers have two communications pins, TXON and RXON, that you can connect
to network activity LEDs (RXACTIVE and TXACTIVE) without any special circuitry
requirements. However, you might want to add pulse-stretching circuitry for these packet-
activity signals for increased visibility. If your device does not require network activity
LEDs, pins 37 and 38 should be treated as No Connect.
Comparison with FT 3120 or FT 3150 Devices
The interconnection with the network transformer for an FT 3120 Smart Transceiver or an
FT 3150 Smart Transceiver is similar to the interconnection for an FT 6000 Smart
Transceiver (as described in Connection for an FT 6000 Smart Transceiver). However, FT
3120 and FT 3150 Smart Transceivers can use one of three transformers: the FT-X1 (a
through-hole part), the FT-X2 (a surface-mount part), or the FT-X3 (a surface-mount part).
Although you can use an FT-X1 or FT-X2 transformer with an FT 6000 Smart Transceiver,
you cannot simply replace an existing FT 3120 or FT 3150 Smart Transceiver with an FT
6000 Smart Transceiver. The voltage requirement is different (the FT 6000 Smart
Series 6000 Chip Data Book 55