MAXIM MAX14950A Technical data

19-5965; Rev 0; 6/11

MAX14950A

Single-Lane PCIe Equalizer/Redriver

General Description

The MAX14950A dual equalizer/redriver improves PCI Express® (PCIe) signal integrity by providing programmable input equalization. This feature reduces deterministic jitter and redrives circuitry to reestablish deemphasis, 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 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.

Applications

Servers

Industrial PCs

Test Equipment

Computers

External Graphics Applications

Communications Switchers

Storage Area Networks

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

 Very Low Latency With 160ps (typ) Propagation Delay  PCIe Gen III (8GT/s)-Compliant Input/Output Return Loss

 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.

For related parts and recommended products to use with this part, refer to www.maxim-ic.com/MAX14950A.related.

Typical Operating Circuit

MAIN BOARD

Tx

PCIe

Rx

PCI Express is a registered service mark of PCI-SIG Corporation.

�� Maxim Integrated Products 1

MAX14950A

MIDPLANE

SINGLE DIFFERENTIAL PAIR

CONNECTORS

REMOTE BOARD

Rx

PCIe

Tx

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.

MAX14950A

Single-Lane PCIe Equalizer/Redriver

ABSOLUTE MAXIMUM RATINGS

(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

(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 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 (BJA) ......... 28NC/W

Junction-to-Case Thermal Resistance (BJC) .................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.maxim-ic.com/thermal-tutorial.

Continuous Power Dissipation (TA = +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

ELECTRICAL CHARACTERISTICS

(VCC = +3.0V to +3.6V, C erwise noted. Typical values are at VCC = +3.3V and TA = +25NC.) (Note 3)

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

DC PERFORMANCE

Power-Supply Range V

Supply Current I

= 200nF coupling capacitor on each output, RL = 50I on each output, TA = 0NC to +70NC, unless oth-

CL

CC

OEQ_2 = OEQ_1 = OEQ_0 = GND

OEQ_2 = OEQ_1 = GND, OEQ_0 = V

OEQ_2 = OEQ_0 = GND, OEQ_1 = V

OEQ_2 = GND, OEQ_1 =

CC

EN = V

OEQ_0 = V

CC

OEQ_2 = VCC, OEQ_1 = OEQ_0 = GND

OEQ_2 = OEQ_0 = VCC, OEQ_1 = GND

OEQ_2 = OEQ_1 = VCC, OEQ_0 = GND

OEQ_2 = OEQ_1 = OEQ_0 = V

CC

3.0 3.3 3.6 V

102 135

106 140

107 140

125 160

mA

106 140

132 170

140 180

165 210

�� Maxim Integrated Products 2

Single-Lane PCIe Equalizer/Redriver

ELECTRICAL CHARACTERISTICS (continued)

(VCC = +3.0V to +3.6V, C erwise noted. Typical values are at VCC = +3.3V and TA = +25NC.) (Note 3)

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

Standby Current I

Differential Input Impedance

Differential Output Impedance

Common-Mode Resistance to GND, Input Termination Not Powered

= 200nF coupling capacitor on each output, RL = 50I on each output, TA = 0NC to +70NC, unless oth-

CL

OEQ_2 = OEQ_1 = OEQ_0 = GND

OEQ_2 = OEQ_1 = GND, OEQ_0 = V

OEQ_2 = OEQ_0 = GND, OEQ_1 = VCC

OEQ_2 = GND, OEQ_1 =

STBY

EN = GND

OEQ_0 = V

OEQ_2 = VCC, OEQ_1 = OEQ_0 = GND

OEQ_2 = OEQ_0 = VCC, OEQ_1 = GND

OEQ_2 = OEQ_1 = VCC, OEQ_0 = GND

OEQ_2 = OEQ_1 = OEQ_0 = V

CC

Z

RX-DIFF-

DC

Z

TX-DIFF-

DC

Z

RX-HIGH-

IMP-DC

DC 80 100 120

-150mV P V

IN_CM

P +200mV

CC

MAX14950A

57 80

61 85

62 85

75 100

62 80

85 110

92 120

120 150

50

mA

I

kI

Common-Mode Resistance to GND, Input Termination Powered

Output Short-Circuit Current I

Common-Mode Delta, Between Active and Idle States

DC Output Offset, During Active State

DC Output Offset, During Electrical Idle

�� Maxim Integrated Products 3

Z

RX-DC

TX-SHORT

V

TX-CMDC-ACTIVEIDLE-DELTA

V

TXACTIVEDIFF-DC

V

TX-IDLE-

DIFF-DC

20 25 30

I

Single-ended (Note 4) 90 mA

100 mV

|(V

OUT_P

- V

)| 50 mV

OUT_M

)| 50 mV

OUT_M

Single-Lane PCIe Equalizer/Redriver

ELECTRICAL CHARACTERISTICS (continued)

(VCC = +3.0V to +3.6V, C erwise noted. Typical values are at VCC = +3.3V and TA = +25NC.) (Note 3)

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

AC PERFORMANCE (Note 4)

Input Return Loss, Differential RL

Input Return Loss, Common Mode

Output Return Loss, Differential RL

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

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, 3dB

= 200nF coupling capacitor on each output, RL = 50I on each output, TA = 0NC to +70NC, unless oth-

CL

f = 0.05GHz to 1.25GHz 10 dB

RX-DIFF

f = 1.25GHz to 2.5GHz 8 dB

f = 2.5GHz to 4GHz 5 dB

RL

RX-CM

f = 0.05GHz to 2.5GHz 6 dB

f = 2.5GHz to 4GHz 4 dB

f = 0.05GHz to 1.25GHz 10 dB

TX-DIFF

f = 1.25GHz to 2.5GHz 8 dB

f = 2.5GHz to 4GHz 4 dB

RL

TX-CM

V

RX-DIFF-

PP

V

TX-DIFF-

PP

V

TX-DE-

RATIO-0dB

V

TX-DE-

RATIO-

3.5dB

V

TX-DE-

RATIO-6dB

V

TX-DE-HA-

RATIO-6dB

V

TX-DE-

PS-RATIO-

3.5dB

V

TX-DE-PS-

RATIO-6dB

V

TX-DE-PS-

RATIO-9dB

V

TX-DE-PS-

HA-RATIO-

9dB

V

RX-EQ-

3dB

f = 0.05GHz to 2.5GHz 6 dB

f = 2.5GHz to 4GHz 4 dB

2 x |(V

OUT_P

- V

OUT_M

)|,

OEQ_2 = OEQ_1 = OEQ_0 = GND

OEQ_2 = OEQ_1 = OEQ_0 = GND, Figure 1

OEQ_2 = OEQ_1 = GND, OEQ_0 = VCC, Figure 1

OEQ_2 = OEQ_0 = GND, OEQ_1 = VCC, Figure 1

OEQ_2 = GND, OEQ_1 = OEQ_0 = VCC, Figure 1

OEQ_2 = VCC, OEQ_1 = OEQ_0 = GND, Figure 1

OEQ_2 = OEQ_0 = VCC, OEQ_1 = GND, Figure 1

OEQ_2 = OEQ_1 = VCC, OEQ_0 = GND, Figure 1

OEQ_2 = OEQ_1 = OEQ_0 = VCC, Figure 1

INEQ_1 = INEQ_0 = GND (Note 5) 3 dB

MAX14950A

100 1200 mV

800 1000 1300 mV

0 dB

3.5 dB

6 dB

3.5 dB

6 dB

9 dB

P-P

�� Maxim Integrated Products 4

MAX14950A

Single-Lane PCIe Equalizer/Redriver

ELECTRICAL CHARACTERISTICS (continued)

(VCC = +3.0V to +3.6V, C erwise noted. Typical values are at VCC = +3.3V and TA = +25NC.) (Note 3)

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

Input Equalization, 5dB

Input Equalization, 7dB

Input Equalization, 9dB

Output Common-Mode Voltage

Propagation Delay t

Rise/Fall Time

Rise/Fall Time Mismatch

Output Skew Same Pair t

Deterministic Jitter t

Random Jitter t

Electrical Idle Entry Delay

Electrical Idle Exit Delay

Electrical Idle Detect Threshold (Note 7)

Output Voltage During Electrical Idle (AC)

Receiver-Detect Pulse Amplitude

Receiver-Detect Pulse Width 100 ns

Receiver-Detect Retry Period 200 ns

= 200nF coupling capacitor on each output, RL = 50I on each output, TA = 0NC to +70NC, unless oth-

CL

V

RX-EQ-

5dB

V

RX-EQ-

7dB

V

RX-EQ-

9dB

V

TX-CM-

AC-PP

PD

t

TX-RISE-

FALL

t

TX-RF-

MISMATCH

SK

TX-DJ-DD

TX-RJ-DD

t

TX-IDLESET-TO-

IDLE

t

TX-IDLE-

TO-DIFF-

DATA

INEQ_1 = GND, INEQ_0 = V

(Note 5) 5 dB

CC

INEQ_1 = VCC, INEQ_0 = GND (Note 5) 7 dB

INEQ_1 = INEQ_0 = V

MAX(V V

OUT_M

OUT_P

)/2

+ V

OUT_M

(Note 5) 9 dB

CC

)/2 - MIN(V

OUT_P

+

100 mV

120 160 240 ps

(Note 6) 20 ps

(Note 6) 3 ps

5 ps

K28.5 pattern, AC-coupled, RL = 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

10.5 23.5 ps

1.5 ps

5 ns

EIL_L = EIH_H = EIH_L = GND 65 175

V

TX-IDLE-

THRESH

V

TX-IDLE-

DIFF-AC-P

V

TX-RCV-

DETECT

EIL_L = EIH_L = GND, EIH_H = V

EIL_L = EIH_H = GND, EIH_L = V

CC

EIL_L = VCC, EIH_H = EIH_L = GND

EIL_L = EIH_H = VCC, EIH_L = GND

|(V

OUT_P

- V

)| 20 mV

OUT_M

Voltage change in positive direction 600 mV

85 215

25 155

V

50 175

IH

20 165

IL

80 205

IH

50 195

IL

mV

P-P

RMS

P-P

�� Maxim Integrated Products 5

MAX14950A

Single-Lane PCIe Equalizer/Redriver

ELECTRICAL CHARACTERISTICS (continued)

(VCC = +3.0V to +3.6V, C erwise noted. Typical values are at VCC = +3.3V and TA = +25NC.) (Note 3)

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

CONTROL LOGIC

Input-Logic Level Low V

Input-Logic Level High V

Input-Logic Hysteresis V

Input Pulldown Resistance R

ESD PROTECTION

ESD Voltage Human Body Model (HBM) ±4 kV

Note 3: All devices are 100% production tested at TA = +70NC. Specifications over operating temperature range are guaranteed

by design.

Note 4: Guaranteed by design, unless otherwise noted. Note 5: Equivalent to same amount of deemphasis driving the input. Note 6: Rise and fall times are measured using 20% and 80% levels. Note 7: Electrical idle detect threshold is measured using D10.2 pattern and data rate = 1GT/s.

= 200nF coupling capacitor on each output, RL = 50I on each output, TA = 0NC to +70NC, unless oth-

CL

IL

IH

HYST

PD

1.4 V

0.1 V

200 375 kI

0.6 V

Figure 1. Illustration of Output Deemphasis

V

LOW_P-P

DE(dB) = 20 log

V

HIGH_P- P

V

LOW_P-P

HIGH_P-P

�� Maxim Integrated Products 6