Datasheet
SLLS363A − SEPTEMBER 1999 − REVISED NOVEMBER 2000
3
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
description (continued)
When the power supply of the TSB41LV06A is off while the twisted-pair cables are connected, the TSB41LV06A
transmitter and receiver circuitry presents a high impedance to the cable and does not load the TPBIAS voltage
at the other end of the cable.
When the TSB41LV06A is used with one or more of the ports not brought out to a connector, the twisted-pair
terminals of the unused ports must be terminated for reliable operation. For each unused port, the TPB+ and
TPB− terminals should be tied together and then pulled to ground, or the TPB+ and TPB− terminals should be
connected to the suggested termination network. The TPA+ and TPA− and TPBIAS terminals of an unused port
may be left unconnected. The TPBIAS terminal may be connected to a 1 µF capacitor to ground or left floating.
The TESTM, SE, and SM terminals are used to set up various manufacturing test conditions. For normal
operation, the TESTM terminal should be connected to V
DD
, SE should be tied to ground through a 1-kΩ resistor,
while SM should be connected directly to ground.
Four package terminals are used as inputs to set the default value for four configuration status bits in the self-ID
packet, and are hardwired high or low as a function of the equipment design. The PC0–PC2 terminals are used
to indicate the default power-class status for the node (the need for power from the cable or the ability to supply
power to the cable). See Table 1 for power-class encoding. The C/LKON terminal is used as an input to indicate
that the node is a contender for either isochronous resource manager (IRM) or bus manager (BM).
The TSB41LV06A supports suspend/resume as defined in the IEEE P1394a specification. The suspend
mechanism allows pairs of directly-connected ports to be placed into a low power conservation state
(suspended state) while maintaining a port-to-port connection between bus segments. While in the suspended
state, a port is unable to transmit or receive data transaction packets. However, a port in the suspended state
is capable of detecting connection status changes and detecting incoming TPBias. When all six ports of the
TSB41LV06A are suspended, all circuits except the bandgap reference generator and bias detection circuits
are powered down resulting in significant power savings. For additional details of suspend/resume operation
refer to the P1394a specification. The use of suspend/resume is recommended for new designs.
The port transmitter and receiver circuitry is disabled during power-down (when the PD input terminal is
asserted high), during reset (when the RESET
input terminal is asserted low), when no active cable is connected
to the port, or when controlled by the internal arbitration logic. The TPBias output is disabled during power down,
during reset, or when the port is disabled as commanded by the LLC.
The CNA (cable-not-active) output terminal is asserted high when there are no twisted-pair cable ports receiving
incoming bias (i.e., they are either disconnected or suspended), and can be used along with LPS to determine
when to power down the TSB41LV06A. The CNA output is not debounced. When the PD terminal is asserted
high, the CNA detection circuitry is enabled (regardless of the previous state of the ports) and a pulldown is
activated on the RESET
terminal so as to force a reset of the TSB41LV06A internal logic.
The LPS (link power status) terminal works with the C/LKON terminal to manage the power usage in the node.
The LPS signal from the LLC is used in conjunction with the LCtrl bit (see Table 1 and Table 2 in the
APPLICATION INFORMATION section) to indicate the active/power status of the LLC. The LPS signal is also
used to reset, disable, and initialize the PHY-LLC interface (the state of the PHY-LLC interface is controlled
solely by the LPS input regardless of the state of the LCtrl bit).
The LPS input is considered inactive if it remains low for more than 2.6 µs and is considered active otherwise.
When the TSB41LV06A detects that LPS is inactive, it places the PHY-LLC interface into a low-power reset state
in which the CTL and D outputs are held in the logic zero state and the LREQ input is ignored; however, the
SYSCLK output remains active. If the LPS input remains low for more than 26 µs, the PHY-LLC interface is put
into a low-power disabled state in which the SYSCLK output is also held inactive. The PHY-LLC interface is also
held in the disabled state during hardware reset. The TSB41LV06A continues the necessary repeater functions
required for normal network operation regardless of the state of the PHY-LLC interface. When the interface is
in the reset or disabled state and LPS is again observed active, the PHY initializes the interface and return it
to normal operation.