MAX14955
Single-Lane PCIe Gen III Redriver
with Equalization and Extended
Temperature Operation
Benefits and Features
The MAX14955 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 stripline,
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 MAX14955 is available in a small, 40-pin, 5.0mm x
5.0mm TQFN package with flow-through traces for opti-
mal layout and minimal space requirements. The device
is specified over the -40°C to +85°C extending operating
temperature range.
General Description
●
Fully Integrated for Ease of Use and Design Flexibility
•
Optimized for PCIe Gen III (8.0GT/s), Gen II
(5.0GT/s), Gen I (2.5 GT/s) Compatible
• Four Levels of Input Equalization up to 16dB
• Eight Levels of Output Deemphasis up to 9dB
●
High Level of Performance to Overcome Noise in
Lossy Channels
• Random Jitter: 0.5ps
RMS
(typ)
• Deterministic Jitter: 7ps
P-P
(typ)
• Equalization Permits Placement Up to 30in FR4
● Robust Solution for Harsh Environments
• Industrial Temperature Rated: -40°C to +85°C
• ±4kV Human Body Model (HBM) Protection on All
Pins
•
Housed in a Flow-Through (5mm x 5mm) TQFN
Package for Resistance to Vibration/Shocks
Ordering Information
appears at end of data sheet.
For related parts and recommended products to use with this part, refer
to
www.maximintegrated.com/MAX14955.related.
Applications
●
●
●
●
●
●
Industrial/Embedded PCs
Computer on Modules
Carrier Boards
Test Equipment
Rack Server Industrial PCs
Medical Equipment
Typical Operating Circuit
MAIN BOARD
MIDPLANE
Tx
MAX14955
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.
19-6640; Rev 0; 3/13
MAX14955
Single-Lane PCIe Gen III Redriver
with Equalization and Extended
Temperature Operation
Continuous Power Dissipation (T
A
= +70°C)
TQFN (derate 35.7mW/°C above +70°C)..................2857mW
Operating Temperature Range
........................... -40°C to +85°C
Junction Temperature Range
........................... -40°C to +150°C
Storage Temperature Range
............................ -65°C to +150°C
Lead Temperature (soldering, 10s) ................................. +300°C
Soldering Temperature (reflow)
.......................................+260°C
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 ...........................................................±30mA
Peak Current IN_P, IN_M, OUT_P, OUT_M
(pulsed for 1µs, 1% duty cycle) ..................................±100mA
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 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.
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
= 50Ω on each output, T
A
= -40°C to +85°C, unless otherwise
noted. Typical values are at V
CC
= +3.3V and T
A
= +25°C.) (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
Supply Current
I
CC
EN = 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
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Maxim Integrated
│
2
MAX14955
Single-Lane PCIe Gen III Redriver
with Equalization and Extended
Temperature Operation
(V
CC
= +3.0V to +3.6V, C
CL
= 200nF coupling capacitor on each output, R
L
= 50Ω on each output, T
A
= -40°C to +85°C, unless otherwise
noted. Typical values are at V
CC
= +3.3V and T
A
= +25°C.) (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
Standby Current
I
STBY
EN = GND
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
Electrical Characteristics (continued)
MIN
TYP
57
61
62
75
62
85
92
120
MAX
80
85
85
100
UNITS
mA
80
110
120
150
120
120
Ω
Ω
kΩ
DC
DC
-150mV ≤ V
IN_CM
≤ +200mV
80
80
50
100
100
Z
TX-DIFF-
DC
Z
RX-HIGH-
IMP-DC
Z
RX-DC
I
TX-SHORT
V
TX-CM-DC-
ACTIVE-IDLE-
DELTA
20
Single-ended (Note 4)
90
25
30
Ω
mA
100
mV
V
TX-
ACTIVE-
DIFF-DC
|(V
OUT_P
- V
OUT_M
)|
|(V
OUT_P
- V
OUT_M
)|
65
65
mV
mV
V
TX-IDLE-
DIFF-DC
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Maxim Integrated
│
3
MAX14955
Single-Lane PCIe Gen III Redriver
with Equalization and Extended
Temperature Operation
(V
CC
= +3.0V to +3.6V, C
CL
= 200nF coupling capacitor on each output, R
L
= 50Ω on each output, T
A
= -40°C to +85°C, unless otherwise
noted. Typical values are at V
CC
= +3.3V and T
A
= +25°C.) (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
Output Deemphasis Ratio, 3.5dB
Output Deemphasis Ratio, 6dB
Output Deemphasis Ratio, 6dB
with Higher Amplitude
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
Electrical Characteristics (continued)
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
1200
1000
0
3.5
6
6
3.5
6
9
9
5
1400
mV
P-P
mV
P-P
dB
dB
dB
dB
dB
dB
dB
dB
dB
V
TX-DIFF-
PP
2 x |(V
OUT_P
- V
OUT_M
)|,
OEQ_2 = OEQ_1 = OEQ_0 = GND
OEQ_2 = OEQ_1 = OEQ_0 = GND,
Figure 1
800
V
TX-DE-
RATIO-0dB
OEQ_2 = OEQ_1 = GND, OEQ_0 = V
CC
,
RATIO-3.5dB
Figure 1
V
TX-DE-
RATIO-6dB
V
TX-DE-
OEQ_2 = OEQ_0 = GND, OEQ_1 = V
CC
,
Figure 1
V
TX-DE-HA-
OEQ_2 = GND, OEQ_1 = OEQ_0 = V
CC
,
RATIO-6dB
Figure 1
Output Deemphasis Ratio, 3.5dB
V
TX-DE-PS-
OEQ_2 = V
CC
, OEQ_1 = OEQ_0 = GND,
with Preshoot
RATIO-3.5dB
Figure 1
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-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
OEQ_2 = OEQ_1 = OEQ_0 = V
CC
,
Figure 1
V
RX-EQ-5dB
INEQ_1 = INEQ_0 = GND (Note 5)
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Maxim Integrated
│
4
MAX14955
Single-Lane PCIe Gen III Redriver
with Equalization and Extended
Temperature Operation
(V
CC
= +3.0V to +3.6V, C
CL
= 200nF coupling capacitor on each output, R
L
= 50Ω on each output, T
A
= -40°C to +85°C, unless otherwise
noted. Typical values are at V
CC
= +3.3V and T
A
= +25°C.) (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
Electrical Idle Entry Delay
SYMBOL
CONDITIONS
MIN
TYP
8
12
16
100
120
(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
7
0.5
5
20
20
23.5
1.5
160
240
MAX
UNITS
dB
dB
dB
mV
P-P
ps
ps
ps
ps
P-P
ps
RMS
ns
Electrical Characteristics (continued)
V
RX-EQ-8dB
INEQ_1 = GND, INEQ_0 = V
CC
(Note 5)
V
RX-EQ-
12dB
INEQ_1 = V
CC
, INEQ_0 = GND (Note 5)
INEQ_1 = INEQ_0 = V
CC
(Note 5)
V
RX-EQ-
16dB
V
TX-CM-AC-
MAX(V
OUT_P
+ V
OUT_M
)/2 - MIN(V
OUT_P
+ V
OUT_M
)/2
PP
t
PD
t
TX-RISE-
FALL
t
TX-RF-
MISMATCH
t
TX-DJ-DD
t
TX-RJ-DD
t
TX-IDLE-
From input to output, D10.2 pattern, data
SET-TO-IDLE
rate = 1GT/s
t
TX-IDLE-
TO-DIFF-
DATA
Electrical Idle Exit Delay
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
50
5
112
112
20
600
100
200
190
ns
Electrical Idle Detect Threshold
Output Voltage During Electrical
Idle (AC)
Receiver-Detect Pulse Amplitude
Receiver-Detect Pulse Width
Receiver-Detect Retry Period
CONTROL LOGIC
Input-Logic Level Low
Input-Logic Level High
Input-Logic Hysteresis
Input Pulldown Resistance
ESD PROTECTION
ESD Voltage
V
TX-IDLE-
THRESH
mV
P-P
V
TX-IDLE-
DIFF-AC-P
mV
P-P
mV
ns
ns
V
TX-RCV-
DETECT
V
IL
V
IH
V
HYST
R
PD
Human Body Model (HBM)
200
1.4
0.1
375
±4
0.6
V
V
V
kΩ
kV
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