MAX14950A
Single-Lane PCIe Equalizer/Redriver
General Description
The MAX14950A dual equalizer/redriver improves PCI
Express
®
(PCIe) signal integrity by providing program-
mable input equalization. This feature reduces deter-
ministic jitter and redrives circuitry to reestablish deem-
phasis, which compensates for circuit-board loss at high
frequencies. The device permits optimal placement of
key PCIe components and allows for longer runs of strip-
line, microstrip, or cable.
The device contains two identical channels capable
of equalizing PCIe Gen III (8GT/s), Gen II (5GT/s), and
Gen I (2.5GT/s) signals and features electrical idle and
receiver detection.
The MAX14950A is available in a small, 40-pin, 5.0mm
x 5.0mm TQFN package with flow-through traces for
optimal layout and minimal space requirements. It is
specified over the 0NC to +70NC commercial operating
temperature range.
Benefits and Features
S
Innovative Design Eliminates Need for Costly
External Components
Single +3.3V Supply Operation
S
Increased Design Flexibility for Backward-
Compatible Applications
Optimized for PCIe Gen III (8GT/s) and
Gen II (5GT/s) Signals and Compatible with
Gen I (2.5GT/s) Signals
S
High Level of Integration for Performance
Random Jitter: 0.5ps
RMS
, Deterministic
Jitter: 7ps
p-p
Four-Level-Programmable Input Equalization
Eight-Level-Programmable Output Emphasis
Electrical Idle Detection
Receiver Detection Permits Completely
Transparent Operation
S
Ideal for Space-Sensitive Applications
On-Chip 50I Input/Output Terminations
40-Pin, 5.0mm x 5.0mm TQFN Packaging
Ordering Information
appears at end of data sheet.
Applications
Servers
Test Equipment
External Graphics Applications
Communications Switchers
Storage Area Networks
For related parts and recommended products to use with this part,
refer to
www.maximintegrated.com/MAX14950A.related.
Typical Operating Circuit
MAIN BOARD
MIDPLANE
Tx
MAX14950A
PCIe
Rx
SINGLE DIFFERENTIAL PAIR
Tx
PCIe
SINGLE DIFFERENTIAL PAIR
Rx
REMOTE BOARD
CONNECTORS
PCI Express is a registered service mark of PCI-SIG Corporation.
For pricing, delivery, and ordering information, please contact Maxim Direct at
1-888-629-4642, or visit Maxim Integrated’s website at www.maximintegrated.com.
19-5965; Rev 1; 4/13
MAX14950A
Single-Lane PCIe Equalizer/Redriver
ABSOLUTE MAXIMUM RATINGS
(Voltages referenced to GND.)
V
CC
.......................................................................-0.3V to +4.0V
All Other Pins (Note 1) ............................. -0.3V to (V
CC
+ 0.3V)
Continuous Current IN_P, IN_M,
OUT_P, OUT_M ...........................................................
Q30mA
Peak Current IN_P, IN_M, OUT_P, OUT_M
(pulsed for 1Fs, 1% duty cycle) ................................
Q100mA
Note 1:
All I/O pins are clamped by internal diodes.
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional opera-
tion 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.
Continuous Power Dissipation (T
A
= +70NC)
TQFN (derate 35.7mW/NC above +70NC)..................2857mW
Operating Temperature Range ............................. 0NC to +70NC
Junction Temperature Range........................... -40NC to +150NC
Storage Temperature Range............................ -65NC to +150NC
Lead Temperature (soldering, 10s) ................................+300NC
Soldering Temperature (reflow) ......................................+260NC
PACKAGE THERMAL CHARACTERISTICS (Note 2)
TQFN
Junction-to-Ambient Thermal Resistance (B
JA
) ......... 28NC/W
Junction-to-Case Thermal Resistance (B
JC
) .................2NC/W
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.maximintegrated.com/thermal-tutorial.
(V
CC
= +3.0V to +3.6V, C
CL
= 200nF coupling capacitor on each output, R
L
= 50I on each output, T
A
= 0NC to +70NC, unless oth-
erwise noted. Typical values are at V
CC
= +3.3V and T
A
= +25NC.) (Note 3)
PARAMETER
DC PERFORMANCE
Power-Supply Range
V
CC
OEQ_2 = OEQ_1 = OEQ_0
= GND
OEQ_2 = OEQ_1 = GND,
OEQ_0 = V
CC
OEQ_2 = OEQ_0 = GND,
OEQ_1 = V
CC
OEQ_2 = GND, OEQ_1 =
OEQ_0 = V
CC
OEQ_2 = V
CC
, OEQ_1 =
OEQ_0 = GND
OEQ_2 = OEQ_0 = V
CC
,
OEQ_1 = GND
OEQ_2 = OEQ_1 = V
CC
,
OEQ_0 = GND
OEQ_2 = OEQ_1 = OEQ_0
= V
CC
3.0
3.3
102
106
107
125
106
132
140
165
3.6
135
140
140
160
mA
140
170
180
210
V
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
ELECTRICAL CHARACTERISTICS
Supply Current
I
CC
EN = V
CC
Maxim Integrated
2
MAX14950A
Single-Lane PCIe Equalizer/Redriver
ELECTRICAL CHARACTERISTICS (continued)
(V
CC
= +3.0V to +3.6V, C
CL
= 200nF coupling capacitor on each output, R
L
= 50I on each output, T
A
= 0NC to +70NC, unless oth-
erwise noted. Typical values are at V
CC
= +3.3V and T
A
= +25NC.) (Note 3)
PARAMETER
SYMBOL
CONDITIONS
OEQ_2 = OEQ_1 = OEQ_0
= GND
OEQ_2 = OEQ_1 = GND,
OEQ_0 = V
CC
OEQ_2 = OEQ_0 = GND,
OEQ_1 = V
CC
OEQ_2 = GND, OEQ_1 =
OEQ_0 = V
CC
OEQ_2 = V
CC
, OEQ_1 =
OEQ_0 = GND
OEQ_2 = OEQ_0 = V
CC
,
OEQ_1 = GND
OEQ_2 = OEQ_1 = V
CC
,
OEQ_0 = GND
OEQ_2 = OEQ_1 = OEQ_0
= V
CC
Differential Input Impedance
Differential Output Impedance
Common-Mode Resistance to
GND, Input Termination Not
Powered
Common-Mode Resistance to
GND, Input Termination Powered
Output Short-Circuit Current
Common-Mode Delta, Between
Active and Idle States
DC Output Offset, During Active
State
DC Output Offset, During
Electrical Idle
Z
RX-DIFF-
DC
MIN
TYP
57
61
62
75
62
85
92
120
MAX
80
85
85
100
UNITS
Standby Current
I
STBY
EN = GND
mA
80
110
120
150
120
120
I
I
DC
DC
80
80
100
100
Z
TX-DIFF-
DC
Z
RX-HIGH-
IMP-DC
-150mV
P
V
IN_CM
P
+200mV
50
kI
Z
RX-DC
I
TX-SHORT
V
TX-CM-
DC-ACTIVE-
IDLE-DELTA
20
Single-ended (Note 4)
90
25
30
I
mA
100
mV
V
TX-
ACTIVE-
DIFF-DC
|(V
OUT_P
- V
OUT_M
)|
|(V
OUT_P
- V
OUT_M
)|
65
mV
V
TX-IDLE-
DIFF-DC
65
mV
Maxim Integrated
3
MAX14950A
Single-Lane PCIe Equalizer/Redriver
ELECTRICAL CHARACTERISTICS (continued)
(V
CC
= +3.0V to +3.6V, C
CL
= 200nF coupling capacitor on each output, R
L
= 50I on each output, T
A
= 0NC to +70NC, unless oth-
erwise noted. Typical values are at V
CC
= +3.3V and T
A
= +25NC.) (Note 3)
PARAMETER
AC PERFORMANCE (Note 4)
f = 0.05GHz to 1.25GHz
Input Return Loss, Differential
Input Return Loss, Common
Mode
Output Return Loss, Differential
Output Return Loss, Common
Mode
Redriver-Operation Differential
Input-Signal Range
Full-Swing Differential Output
Voltage (No Deemphasis)
Output Deemphasis Ratio, 0dB
RL
RX-DIFF
f = 1.25GHz to 2.5GHz
f = 2.5GHz to 4GHz
RL
RX-CM
f = 0.05GHz to 2.5GHz
f = 2.5GHz to 4GHz
f = 0.05GHz to 1.25GHz
RL
TX-DIFF
f = 1.25GHz to 2.5GHz
f = 2.5GHz to 4GHz
RL
TX-CM
V
RX-DIFF-
PP
SYMBOL
CONDITIONS
MIN
9
8
5
6
4
10
8
4
6
4
100
TYP
MAX
UNITS
dB
dB
dB
dB
dB
dB
dB
dB
dB
dB
f = 0.05GHz to 2.5GHz
f = 2.5GHz to 4GHz
1400
1000
0
1400
mV
P-P
mV
P-P
dB
V
TX-DIFF-
PP
OEQ_2 = OEQ_1 = OEQ_0 = GND
OEQ_2 = OEQ_1 = OEQ_0 = GND,
Figure 1
OEQ_2 = OEQ_1 = GND, OEQ_0 = V
CC
,
Figure 1
OEQ_2 = OEQ_0 = GND, OEQ_1 = V
CC
,
Figure 1
800
V
TX-DE-
RATIO-0dB
Output Deemphasis Ratio, 3.5dB
V
TX-DE-
RATIO-
3.5dB
3.5
dB
Output Deemphasis Ratio, 6dB
Output Deemphasis Ratio, 6dB
with Higher Amplitude
Output Deemphasis Ratio, 3.5dB
with Preshoot
Output Deemphasis Ratio, 6dB
with Preshoot
Output Deemphasis Ratio, 9dB
with Preshoot
Output Deemphasis Ratio,
9dB with Preshoot and Higher
Amplitude
Input Equalization, 5dB
V
TX-DE-
RATIO-6dB
6
6
dB
dB
V
TX-DE-HA-
OEQ_2 = GND, OEQ_1 = OEQ_0 = V
CC
,
RATIO-6dB
Figure 1
V
TX-DE-
PS-RATIO-
3.5dB
OEQ_2 = V
CC
, OEQ_1 = OEQ_0 = GND,
Figure 1
3.5
dB
V
TX-DE-PS-
OEQ_2 = OEQ_0 = V
CC
, OEQ_1 = GND,
RATIO-6dB
Figure 1
V
TX-DE-PS-
OEQ_2 = OEQ_1 = V
CC
, OEQ_0 = GND,
RATIO-9dB
Figure 1
V
TX-DE-PS-
HA-RATIO-
9dB
6
9
dB
dB
OEQ_2 = OEQ_1 = OEQ_0 = V
CC
,
Figure 1
INEQ_1 = INEQ_0 = GND (Note 5)
9
dB
V
RX-EQ-
5dB
5
dB
Maxim Integrated
4
MAX14950A
Single-Lane PCIe Equalizer/Redriver
ELECTRICAL CHARACTERISTICS (continued)
(V
CC
= +3.0V to +3.6V, C
CL
= 200nF coupling capacitor on each output, R
L
= 50I on each output, T
A
= 0NC to +70NC, unless oth-
erwise noted. Typical values are at V
CC
= +3.3V and T
A
= +25NC.) (Note 3)
PARAMETER
Input Equalization, 8dB
Input Equalization, 12dB
Input Equalization, 16dB
Output Common-Mode Voltage
Propagation Delay
Rise/Fall Time
Rise/Fall Time Mismatch
Deterministic Jitter
Random Jitter
SYMBOL
V
RX-EQ-
8dB
CONDITIONS
INEQ_1 = GND, INEQ_0 = V
CC
(Note 5)
INEQ_1 = V
CC
, INEQ_0 = GND (Note 5)
INEQ_1 = INEQ_0 = V
CC
(Note 5)
MAX(V
OUT_P
+ V
OUT_M
)/2 - MIN(V
OUT_P
+
V
OUT_M
)/2
MIN
TYP
8
12
16
MAX
UNITS
dB
dB
dB
V
RX-EQ-
12dB
V
RX-EQ-
16dB
V
TX-CM-
AC-PP
100
90
160
240
mV
P-P
ps
ps
t
PD
t
TX-RISE-
FALL
(Note 6)
(Note 6)
K28.5 pattern, AC-coupled, R
L
= 50I, no
deemphasis, no preshoot, data rate = 8GT/s
D10.2 pattern, no deemphasis, no
preshoot, data rate = 8GT/s
From input to output, D10.2 pattern, data
rate = 1GT/s
From input to output, D10.2 pattern, data
rate = 1GT/s
D10.2 pattern, data rate = 1GT/s (Note 3)
D10.2 pattern, data rate = 1GT/s to 8GT/s
|(V
OUT_P
- V
OUT_M
)|
Voltage change in positive direction
20
20
7
0.5
23.5
1.5
t
TX-RF-
MISMATCH
ps
ps
P-P
ps
RMS
ns
t
TX-DJ-DD
t
TX-RJ-DD
t
TX-IDLE-
SET-TO-
IDLE
Electrical Idle Entry Delay
5
Electrical Idle Exit Delay
t
TX-IDLE-
TO-DIFF-
DATA
5
ns
Electrical Idle Detect Threshold
V
TX-IDLE-
THRESH
50
112
112
190
mV
P-P
Output Voltage During Electrical
Idle (AC)
Receiver-Detect Pulse Amplitude
V
TX-IDLE-
DIFF-AC-P
20
600
mV
P-P
mV
V
TX-RCV-
DETECT
Maxim Integrated
5
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