SY58620L_06 Datasheet, PDF (5/18 Pages) Micrel Semiconductor – Precision 4.25Gbps CML Backplane Transceiver with Integrated Loopback

Micrel, Inc.
SY58620L
Outputs
Pin Number
22
19
17, 16
5, 6
8
10
Pin Name
LOS
LOSLVL
RXQ, /RXQ
TXQ, /TXQ
VREF_CTRL
TXVREF-AC
Pin Description
Loss-of-Signal Output. TTL-compatible output with internal 4.75kΩ pull-up resistor. Loss-of-
Signal asserts to logic HIGH when the receiver input amplitudes falls below the threshold set
by LOSLVL.
RX Loss-of-Signal Level Set. A resistor (RLOSLVL) connected between LOSLVL and VCC sets
the threshold for the data input amplitude at which the LOS output is asserted. Default is max
sensitivity. LOSLVL is used to set the Loss-of-Signal (LOS) voltage. It is internally connected
to a 2.8kΩ pull-down resistor to an internal VREF voltage source. See “Typical Operating
Characteristics,” and “Application Implementation” sections for more details.
Receiver Differential Output. Output is CML compatible. Refer to the “Truth Table” and
“Output Stage” sections for more details. Unused output pair may be left open. The output is
designed to drive 400mV (800mVPP) into 50Ω to VCC or 100Ω across the pair.
Transmitter Differential Variable Swing Output. Output is CML compatible. Please refer to the
“Truth Table” and “Output Stage” sections for more details. Unused output pair may be left
open. The output is designed to drive 80mV (160mVPP) min swing to 400mV (800mVPP) typ.
swing into 50Ω to VCC_TXQ or drive 100Ω across the pair depending on TXVCTRL.
Transmitter Output Reference Voltage. Output biases to VCC_TXQ-1.3V. Connecting VREF_CTRL
to TXVCTRL sets the transmitter output swing to max swing.
Transmitter Input Reference Voltage. This output biases to VCC-1.3V. It is used when AC
coupling the transmitter input. For AC-coupled applications, connect TXVREF-AC to the
TXVT pin and bypass with a 0.01µF low ESR capacitors to VCC. See “Input Stage” section for
more details. Maximum sink/source current is ±1.5mA.
Power Pins
Pin Number
3, 24
12, 15, 18
21
4
Pin Name
GND,
Exposed Pad
VCC
VCC_RXIN
VCC_TXQ
Pin Description
Ground. GND pins and exposed pad must be connected to the same ground plane.
3.3V ±10% Positive Power Supply. Bypass with 0.1µF//0.01µF low ESR capacitors and place
as close to each VCC pins as possible. Power pins are not connected internally and must be
connected to the same power supply externally.
3.3V ±10% Receive Input Power Supply. Bypass with 0.1µF//0.01µF low ESR capacitors and
place as close to the VCC_RXIN pin as possible. Power pins are not connected internally and
must be connected to the same power supply externally.
3.3V ±10% Output Transmit Power Supply. Bypass with 0.1µF//0.01µF low ESR capacitors
and place as close to the VCC_TXQ pin as possible. Power pins are not connected internally
and must be connected to the same power supply externally.
Truth Table
LOOPBACK
0
1
RXQ
RXIN
TXIN
TXQ
TXIN
RXIN
January 2006
5
M9999-012006-C
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