_______________________________________________________________ Maxim Integrated Products 1
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.
PCIe, Single Lane, 2:1/1:2 Multiplexer and
Redriver with Equalization
MAX4969
General Description
The MAX4969 active 2:1 and 1:2 multiplexer equalizes
and redrives PCIeM signals up to 5.0GT/s (Gigatransfers
per second) and operates from a single +3.3V supply.
The MAX4969 features PCIe-required electrical idle and
receiver detection on each channel, and improves signal
integrity at the receiver through independent program-
mable input equalization and output deemphasis.
The MAX4969 is available in a small, 42-pin (3.5mm x
9.0mm) TQFN package optimal for simplified layout and
space-saving requirements. The MAX4969 is specified
over the 0NC to +70NC commercial operating tempera-
ture range.
Applications
Blade Servers
Workstations
Communications Switches
Test Equipment
Storage Area Network
Features
S Single +3.3V Supply Operation
S PCIe Gen 1 (2.5GT/s) and Gen 2 (5.0GT/s)
Return Loss ≥ 8dB (1.25GHz ≤ f ≤ 2.5GHz)
S Independent Input Equalization
S Independent Output Deemphasis
S Independent Output Level Selection
Reduced Power and EMI
S On-Chip 50I Input/Output Terminations
S Inline Signal Traces for Simplified Layout
S Space-Saving, 3.5mm x 9.0mm TQFN Package
19-4810; Rev 0; 7/09
Pin Configuration
Ordering Information
+Denotes a lead(Pb)-free/RoHS-compliant package.
*EP = Exposed pad.
PCIe is a registered trademark of PCI-SIG Corp.
TOP VIEW
TQFN
18
19
20
21
INEQA1
INEQA0
INEQB1
INEQB0
42 +
41
40
39
ODEA1
ODEA0
ODEB1
ODEB0
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17
38 37 36 35 34 33 32 31 30 29 28 27 26 25 24 23 22
OUTP
OUTM
GND
ODE1
ODE0
VCC
GND
EN
SEL2
SEL1
GND
INM
INP
GND
INEQ0
INEQ1
VCC
INAM
GND
INBP
INBM
GND
VCC
INAP
GND
RX_DET
GND
OUTBM
OUTBP
GND
OUTAM
OUTAP
GND
VCC
*CONNECT EXPOSED PAD (EP) TO GND.
*EP
MAX4969
PART TEMP RANGE PIN-PACKAGE
MAX4969CTO+ 0NC to +70NC42 TQFN-EP*
PCIe, Single Lane, 2:1/1:2 Multiplexer and
Redriver with Equalization
MAX4969
2
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute
maximum rating conditions for extended periods may affect device reliability.
(Voltages referenced to GND.)
VCC .......................................................................-0.3V to +4.0V
All Other Pins (Note 1) ............................ -0.3V to (VCC + 0.3V)
Continuous Current, IN_P, IN_M, OUT_P, OUT_M ......... Q30mA
Peak Current, IN_P, IN_M, OUT_P,
OUT_M (for 10kHz, 1% duty cycle) .......................... Q100mA
Continuous Power Dissipation (TA = +70NC)
42-Pin TQFN (derate 34.5mW/NC above +70NC) ......2758mW
Junction-to-Case Thermal Resistance
BJC (Note 2) ................................................................ +2NC/W
Junction-to-Ambient Thermal Resistance
BJA (Note 2) .............................................................. +29NC/W
Operating Temperature Range ............................. 0NC to +70NC
Junction Temperature Range ........................... -40NC to +150NC
Storage Temperature Range ............................ -65NC to +150NC
Lead Temperature (soldering, 10s) ................................+300NC
ELECTRICAL CHARACTERISTICS
(VCC = +3.0V to +3.6V, CCL = 75nF coupling capacitor on each output, RL = 50I on each output, TA = 0NC to +70NC, unless other-
wise noted. Typical values are at VCC = +3.3V and TA = +25NC.) (Note 3)
ABSOLUTE MAXIMUM RATINGS
Note 1: All I/O pins are clamped by internal diodes.
Note 2: Package thermal resistances were obtained using the method described in JEDEC specification JESD51-7, using a four-
layer board. For detailed information on package thermal considerations, refer to www.maxim-ic.com/thermal-tutorial.
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
DC PERFORMANCE
Power-Supply Range VCC 3.0 3.6 V
Supply Current ICC EN = VCC INEQ_ = ODE_ = GND 120 150
mAINEQ_ = ODE_ = VCC 160 200
EN = GND 50
Input Impedance, Differential ZRX-DIFF-DC DC 80 100 120 I
Output Impedance, Differential ZTX-DIFF-DC DC 80 100 120 I
Common-Mode Resistance to
GND, Input Terminations Not
Powered
ZRX-HIGH-IMP-
DC-POS VIN_P = VIN_M = 0 to 200mV 50 kI
ZRX-HIGH-IMP-
DC-NEG VIN_P = VIN_M = -150mV to 0V 1 kI
Common-Mode Resistance
to GND, Input Terminations
Powered
ZRX-DC DC 40 50 60 I
Output Short-Circuit Current ITX-SHORT Single-ended (Note 4) 90 mA
Common-Mode Delta, Between
Active and Idle States
VTX-CM-DC-
ACTIVE-IDLE-
DELTA
-100 +100 mV
DC Output Offset, During
Active State
VTX-CM-DC-
LINE-DELTA
Difference between DC average of
VOUT_P and VOUT_M -25 +25 mV
DC Output Offset, During
Electrical Idle
VTX-IDLE-DIFF-
DC ABS(VOUT_P - VOUT_M) -10 +10 mV
AC PERFORMANCE
Input Return Loss, Differential RLRX-DIFF 0.05GHz < f P 1.25GHz (Note 4) 10 dB
1.25GHz < f P 2.5GHz (Note 4) 8 dB
PCIe, Single Lane, 2:1/1:2 Multiplexer and
Redriver with Equalization
MAX4969
3
ELECTRICAL CHARACTERISTICS (continued)
(VCC = +3.0V to +3.6V, CCL = 75nF coupling capacitor on each output, RL = 50I on each output, TA = 0NC to +70NC, unless other-
wise noted. Typical values are at VCC = +3.3V and TA = +25NC.) (Note 3)
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
Input Return Loss, Common
Mode RLRX-CM 0.05GHz < f P 2.5GHz (Note 4) 6 dB
Output Return Loss, Differential RLTX-DIFF 0.05GHz < f P 1.25GHz (Note 4) 10 dB
1.25GHz < f P 2.5GHz (Note 4) 8 dB
Output Return Loss, Common
Mode RLTX-CM 0.05GHz < f P 2.5GHz (Note 4) 6 dB
Differential Input Signal Range,
Redriver Operation VRX-DIFF-PP 0.05GHz < f P 2.5GHz 150 1200 mVP-P
Differential Output Voltage, Full
Swing, No Deemphasis VTX-DIFF-PP
2 x ABS(VOUT_P - VOUT_M),
ODE_1 = GND, ODE_0 = VCC
(see Table 1), f = 500MHz
800 1000 1200 mVP-P
Differential Output Voltage, Low
Swing, No Deemphasis
VTX-DIFF-PP-
LOW
2 x ABS(VOUT_P - VOUT_M),
ODE_1 = ODE_0 = GND (see Table 1),
f = 500MHz
600 750 900 mVP-P
Output Deemphasis Ratio, 0dB VTX-DE-RATIO-
0dB
f = 2.5GHz, ODE_1 = GND, ODE_0 =
VCC or GND, Figure 1 (see Table 1) 0 dB
Output Deemphasis Ratio,
3.5dB
VTX-DE-RATIO-
3.5dB
f = 2.5GHz, ODE_1 = VCC,
ODE_0 = GND, Figure 1 (see Table 1) 3.5 dB
Output Deemphasis Ratio, 6dB VTX-DE-RATIO-
6dB
f = 2.5GHz, ODE_1 = VCC,
ODE_0 = VCC, Figure 1 (see Table 1) 6 dB
Input Equalization, 0dB VRX-EQ-0dB f = 2.5GHz, INEQ_1 = GND,
INEQ_0 = GND or VCC (see Table 2) 0 dB
Input Equalization, 3.5dB VRX-EQ-3.5dB f = 2.5GHz, INEQ_1 = VCC,
INEQ_0 = GND (see Table 2) 3.5 dB
Input Equalization, 6dB VRX-EQ-6dB f = 2.5GHz, INEQ_1 = VCC, INEQ_0 =
VCC (see Table 2) 6 dB
Output Common-Mode Voltage VTX-CM-AC-PP MAX(VOUT_P + VOUT_M)/2 -
MIN(VOUT_P + VOUT_M)/2 (Note 4) 100 mVP-P
Propagation Delay TPD (Note 4) 160 280 400 ps
Rise/Fall Time TTX-RISE-FALL (Notes 4, 5) 30 ps
Rise/Fall Time Mismatch TTX-RF-
MISMATCH (Notes 4, 5) 20 ps
Output Skew Same Pair TSK (Note 4) 10 15 ps
Deterministic Jitter TTX-DJ-DD
K28.5 P pattern, AC-coupled, RL = 50I,
effects of deemphasis deembedded
(Note 4), 5GT/s
20 psP-P
Random Jitter TTX-RJ-DD D10.2 pattern, f > 1.5MHz 0.5 1.4 psRMS
Electrical Idle Entry Delay TTX-IDLE-SET-
TO-IDLE From input to output 15 ns
Electrical Idle Exit Delay TTX-IDLE-TO-
DIFF-DATA From input to output 8 ns
PCIe, Single Lane, 2:1/1:2 Multiplexer and
Redriver with Equalization
MAX4969
4
ELECTRICAL CHARACTERISTICS (continued)
(VCC = +3.0V to +3.6V, CCL = 75nF coupling capacitor on each output, RL = 50I on each output, TA = 0NC to +70NC, unless other-
wise noted. Typical values are at VCC = +3.3V and TA = +25NC.) (Note 3)
Note 3: All devices are 100% production tested at TA = +70NC. Specifications for all temperature limits are guaranteed by design.
Note 4: Guaranteed by design.
Note 5: Rise and fall times are measured using 20% and 80% levels.
Timing Diagram
Figure 1. Illustration of Output Deemphasis
VLOW_P-P VHIGH_P-P
VHIGH_P-P
VLOW_P-P
DE(dB) = 20 log
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
Electrical Idle Detect Threshold VTX-IDLE-
THRESH 65 100 120 mVP-P
Output Voltage During
Electrical Idle (AC)
VTX-IDLE-DIFF-
AC-P ABS(VOUT_P - VOUT_M) 35 mVP-P
Receiver Detect Pulse
Amplitude
VTX-RCV-
DETECT
Voltage change in positive direction
(Note 4) 600 mV
Receiver Detect Pulse Width 100 ns
Receiver Detect Retry Period 200 ns
CONTROL LOGIC
Input Logic-Level Low VIL 0.6 V
Input Logic-Level High VIH 1.4 V
Input Logic Hysteresis VHYST 130 mV
Input Pulldown Resistor RDOWN 37.5 60 150 kW
PCIe, Single Lane, 2:1/1:2 Multiplexer and
Redriver with Equalization
MAX4969
5
Typical Operating Characteristics
(VCC = +3.3V, TA = +25NC, unless otherwise noted.)
VIN = 500mVP-P WITH 19in STRIPLINE,
5GT/s, ODE_ = 01, INEQ_ = 00
50ps/div
200mV/div
1501000 50-100 -50-150
-600
-400
-200
0
200
400
600
MAX4969 toc06
VIN = 500mVP-P WITH 6in STRIPLINE,
5GT/s, ODE_ = 01, INEQ_ = 00
50ps/div
200mV/div
1501000 50-100 -50-150
-600
-400
-200
0
200
400
600
MAX4969 toc05
VIN = 200mVP-P, 5GT/s,
ODE_ = 11, INEQ_ = 00
50ps/div
200mV/div
1501000 50-100 -50-150
-600
-400
-200
0
200
400
600
MAX4969 toc04
VIN = 200mVP-P, 5GT/s,
ODE_ = 10, INEQ_ = 00
50ps/div
200mV/div
1501000 50-100 -50-150
-600
-400
-200
0
200
400
600
MAX4969 toc03
VIN = 200mVP-P, 5GT/s,
ODE_ = 01, INEQ_ = 00
50ps/div
200mV/div
1501000 50-100 -50-150
-600
-400
-200
0
200
400
600
MAX4969 toc02
VIN = 200mVP-P, 5GT/s,
ODE_ = 00, INEQ_ = 00
50ps/div
100mV/div
1501000 50-100 -50-150
-500
-400
-300
-200
-100
0
100
200
300
400
500
MAX4969 toc01
PCIe, Single Lane, 2:1/1:2 Multiplexer and
Redriver with Equalization
MAX4969
6
Typical Operating Characteristics (continued)
(VCC = +3.3V, TA = +25NC, unless otherwise noted.)
VIN = 500mVP-P, 5GT/s, ODE_ = 11,
INEQ_ = 00, AFTER 19in STRIPLINE
50ps/div
100mV/div
1501000 50-100 -50-150
-300
-200
-100
0
100
200
300
MAX4969 toc10
VIN = 500mVP-P, 5GT/s, ODE_ = 01,
INEQ_ = 00, AFTER 19in STRIPLINE
50ps/div
200mV/div
1501000 50-100 -50-150
-600
-400
-200
0
200
400
600
MAX4969 toc09
VIN = 500mVP-P, 5GT/s, ODE_ = 01,
INEQ_ = 00, AFTER 6in STRIPLINE
50ps/div
200mV/div
1501000 50-100 -50-150
-600
-400
-200
0
200
400
600
MAX4969 toc08
VIN = 500mVP-P WITH 19in STRIPLINE,
5GT/s, ODE_ = 01, INEQ_ = 11
50ps/div
200mV/div
1501000 50-100 -50-150
-600
-400
-200
0
200
400
600
MAX4969 toc07
PCIe, Single Lane, 2:1/1:2 Multiplexer and
Redriver with Equalization
MAX4969
7
Pin Description
PIN NAME FUNCTION
1, 17, 22,
38 VCC Power-Supply Input. Bypass VCC to GND with 1FF and 0.01FF capacitors in parallel as close to the
device as possible, recommended on each VCC pin.
2 INEQ1 Channel 1 Input Equalization Control MSB. See Table 2. INEQ1 is internally pulled down by a 60kI
(typ) resistor.
3 INEQ0 Channel 1 Input Equalization Control LSB. See Table 2. INEQ0 is internally pulled down by a 60kI
(typ) resistor.
4, 7, 11, 14,
23, 26, 29,
31, 34, 37
GND Ground
5 INP Channel 1 Noninverting Input
6 INM Channel 1 Inverting Input
8 SEL1 Channel 1 Active Output Selection Input. Drive SEL1 low to activate A outputs. Drive SEL high to
activate B outputs. SEL1 is internally pulled down by a 60kI (typ) resistor.
9 SEL2 Channel 2 Active Input Selection Input. Drive SEL2 low to activate A inputs. Drive SEL high to acti-
vate B inputs. SEL2 is internally pulled down by a 60kI (typ) resistor.
10 EN Enable Input. Drive EN low for reduced power standby mode. Drive EN high for normal operation.
EN is internally pulled down by a 60kI (typ) resistor.
12 OUTP Channel 2 Noninverting Output
13 OUTM Channel 2 Inverting Output
15 ODE1 Channel 2 Output Deemphasis Control MSB. See Table 1. ODE1 is internally pulled down by a 60kI
(typ) resistor.
16 ODE0 Channel 2 Output Deemphasis Control LSB. See Table 1. ODE0 is internally pulled down by a 60kI
(typ) resistor.
18 INEQA1 Channel 2 Input A Equalization Control MSB. See Table 2. INEQA1 is internally pulled down by a
60kI (typ) resistor.
19 INEQA0 Channel 2 Input A Equalization Control LSB. See Table 2. INEQA0 is internally pulled down by a
60kI (typ) resistor.
20 INEQB1 Channel 2 Input B Equalization Control MSB. See Table 2. INEQB1 is internally pulled down by a
60kI (typ) resistor.
21 INEQB0 Channel 2 Input B Equalization Control LSB. See Table 2. INEQB0 is internally pulled down by a
60kI (typ) resistor.
24 INBM Channel 2 Inverting Input B
25 INBP Channel 2 Noninverting Input B
27 INAM Channel 2 Inverting Input A
28 INAP Channel 2 Noninverting Input A
30 RX_DET Receiver Detection Control Bit. Toggle RX_DET to initiate receiver detection. RX_DET is internally
pulled down by a 60kI (typ) resistor.
32 OUTBM Channel 1 Inverting Output B
33 OUTBP Channel 1 Noninverting Output B
35 OUTAM Channel 1 Inverting Output A
36 OUTAP Channel 1 Noninverting Output A
39 ODEB0 Channel 1 Output B Deemphasis Control LSB. See Table 1. ODEB0 is internally pulled down by a
60kI (typ) resistor.
PCIe, Single Lane, 2:1/1:2 Multiplexer and
Redriver with Equalization
MAX4969
8
Pin Description
Functional Diagram
MAX4969
VCC
VCC
CHANNEL 1
CONTROL
GLOBAL CONTROL
ODEB0
OUTAP
OUTAM
OUTBP
OUTBM
INAP
INAM
INBP
INBM
ODEB1
ODEA0
ODEA1
INEQ1
INEQ0
SEL1
EN
RX_DET
INP
INM
CHANNEL 2
CONTROL
SEL2
ODE1
GND
ODE0
INEQA1
INEQA0
INEQB1
INEQB0
OUTP
OUTM
VCC
VCC
PIN NAME FUNCTION
40 ODEB1 Channel 1 Output B Deemphasis Control MSB. See Table 1. ODEB1 is internally pulled down by a
60kI (typ) resistor.
41 ODEA0 Channel 1 Output A Deemphasis Control LSB. See Table 1. ODEA0 is internally pulled down by a
60kI (typ) resistor.
42 ODEA1 Channel 1 Output A Deemphasis Control MSB. See Table 1. ODEA1 is internally pulled down by a
60kI (typ) resistor.
— EP Exposed Pad. Internally connected to GND. Connect EP to a large ground plane to maximize ther-
mal performance. EP is not intended as an electrical connection point.
PCIe, Single Lane, 2:1/1:2 Multiplexer and
Redriver with Equalization
MAX4969
9
Detailed Description
The MAX4969 is an active 2:1/1:2 multiplexer designed
to equalize and redrive PCIe signals up to 5.0GT/s. The
MAX4969 features PCIe-required electrical idle and
receiver detection on each channel, and improves signal
integrity at the receiver through independent program-
mable input equalization and output deemphasis.
Enable Input (EN)
The MAX4969 features an active-high enable input (EN).
EN has an internal pulldown resistor of 60kI (typ). When
EN is driven low or left unconnected, the MAX4969
enters reduced power standby mode and the redrivers
are disabled. Drive EN high for normal operation.
Active Input/Output Select (SEL1, SEL2)
SEL1 selects the active output for channel 1 and SEL2
selects the active input for channel 2. Drive SEL1 or
SEL2 low or leave unconnected to activate A inputs or
outputs. Drive SEL1 or SEL2 high to activate B inputs or
outputs. SEL1 and SEL2 have internal pulldown resistors
of 60kI (typ).
Programmable Output Deemphasis
(ODE_0, ODE_1)
The MAX4969 features independent programmable out-
put deemphasis capable of providing 0dB, 3.5dB, or
6dB deemphasis on any channel. When both ODE_0 and
ODE_1 are driven low or left unconnected, the output is
in low-swing mode (750mV typ) (see Table 1). ODE0,
ODE1, ODEA0, ODEA1, ODEB0, and ODEB1 have inter-
nal pulldown resistors of 60kI (typ).
Programmable Input Equalization
(INEQ_0, INEQ_1)
The MAX4969 features independent programmable
input equalization capable of providing 0dB, 3.5dB, or
6dB of high-frequency equalization on any channel (see
Table 2.) INEQ0, INEQ1, INEQA0, INEQA1, INEQB0, and
INEQB1 have internal pulldown resistors of 60kI (typ).
Receiver Detection (RX_DET)
The MAX4969 features receiver detection on each chan-
nel. Receiver detection initializes on the rising edge
of EN, or upon initial power-up if EN is high. Receiver
detection can also be initiated on a rising or falling edge
of the RX_DET, SEL1, or SEL2 inputs when EN is high.
During this time, the part remains in reduced power
standby mode and the outputs are squelched, despite
the logic-high state of EN. Once started, receiver detec-
tion repeats indefinitely on each channel. Once a receiv-
er is detected on one of the channels, up to 216 more
attempts are made on the other channel. Upon receiver
detection, channel output and electrical idle detection
are enabled (see Table 3). RX_DET has an internal pull-
down resistor of 60kI (typ).
Electrical Idle Detection
The MAX4969 features electrical idle detection to pre-
vent unwanted noise from being redriven at the output.
If the MAX4969 detects that the differential input has
fallen below VTX-IDLE-THRESH, the MAX4969 squelches
the output. For differential input signals that are above
VTX-IDLE-THRESH, the MAX4969 turns on the output and
redrives the signal.
Table 1. Output Deemphasis
Table 3. Receiver Detection
Table 2. Input Equalization
X = Don’t Care
X = Don’t Care
ODE_1 ODE_0 OUTPUT DEEMPHASIS
(dB)
0 0 0, low swing
0 1 0, full swing
1 0 3.5, full swing
1 1 6, full swing
INEQ_1 INEQ_0 INPUT EQUALIZATION
(dB)
0 X 0
1 0 3.5
1 1 6
RX_DET/
SEL1/SEL2 EN DESCRIPTION
X 0 Receiver detection inactive
0 1 Following a rising or falling edge; indefinite retry until receiver detected
Rising or falling edge 1 Initiate receiver detection
1 1 Following a rising or falling edge; indefinite retry until receiver detected
PCIe, Single Lane, 2:1/1:2 Multiplexer and
Redriver with Equalization
MAX4969
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied.
Maxim reserves the right to change the circuitry and specifications without notice at any time.
10 Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600
© 2009 Maxim Integrated Products Maxim is a registered trademark of Maxim Integrated Products, Inc.
Applications Information
Layout
Circuit board layout and design can significantly affect
the performance of the MAX4969. Use good high-fre-
quency design techniques, including minimizing ground
inductance and using controlled-impedance transmis-
sion lines on data signals. It is recommended to run
receive and transmit on different layers to minimize
crosstalk and to place 1FF and 0.01FF power-supply
bypass capacitors in parallel as close to VCC as possible
on each VCC pin. Always connect VCC to a power plane.
Exposed Pad Package
The exposed-pad, 42-pin TQFN package incorporates
features that provide a very low thermal resistance path
for heat removal from the IC. The exposed pad on the
MAX4969 must be soldered to the circuit board ground
plane for proper thermal performance. For more informa-
tion on exposed-pad packages, refer to Application Note
862: HFAN-08.1: Thermal Considerations of QFN and
Other Exposed-Paddle Packages.
Power-Supply Sequencing
Caution: Do not exceed the absolute maximum rat-
ings because stresses beyond the listed ratings may
cause permanent damage to the device.
Proper power-supply sequencing is recommended for
all devices. Always apply GND then VCC before apply-
ing signals, especially if the signal is not current limited.
Chip Information
PROCESS: BiCMOS
Package Information
For the latest package outline information and land pat-
terns, go to www.maxim-ic.com/packages. Note that
a “+”, “#”, or “-” in the package code indicates RoHS
status only. Package drawings may show a different suf-
fix character, but the drawing pertains to the package
regardless of RoHS status.
Typical Application Circuit
MAX4969
IN
OUT
Tx
OUTA
OUTB
INA
INB
Rx
PCIe
HOST
Rx
Tx
PCIe
DEVICE B
Rx
Tx
PCIe
DEVICE A
PACKAGE TYPE PACKAGE CODE DOCUMENT NO.
42 TQFN-EP T423590+1 21-0181
