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

Single-Lane PCIe Equalizer/Redriver

(VCC = +3.3V, TA = +25NC, unless otherwise noted.)

MAX14950A

Typical Operating Characteristics

DATA RATE = 5Gbps,

INEQ_0 = INEQ_1 = 0, V

0EQ_0 = 0, OEQ_1 = 0, OEQ_2 = 0

600

400

200

0

VOLTAGE (mV)

-200

-400

-600

-200 150100500-50-100-150 TIME (ps)

DATA RATE = 5Gbps,

INEQ_0 = INEQ_1 = 0, V

0EQ_0 = 0, OEQ_1 = 0, OEQ_2 = 0

600

400

200

0

VOLTAGE (mV)

-200

-400

-600

-200 150100500-50-100-150 TIME (ps)

= 200mV

IN

= 200mV

IN

P-P

,

MAX14950A toc01

MAX14950A toc04

DATA RATE = 5Gbps,

INEQ_0 = INEQ_1 = 0, V

0EQ_0 = 0, OEQ_1 = 0, OEQ_2 = 0

600

400

200

0

VOLTAGE (mV)

-200

-400

-600

-200 150100500-50-100-150 TIME (ps)

DATA RATE = 5Gbps,

INEQ_0 = INEQ_1 = 0, V

0EQ_0 = 0, OEQ_1 = 0, OEQ_2 = 0

600

400

200

0

VOLTAGE (mV)

-200

-400

-600

-200 150100500-50-100-150 TIME (ps)

= 200mV

IN

= 200mV

IN

P-P

,

MAX14950A toc02

MAX14950A toc05

DATA RATE = 5Gbps,

INEQ_0 = INEQ_1 = 0, V

0EQ_0 = 0, OEQ_1 = 0, OEQ_2 = 0

600

400

200

0

VOLTAGE (mV)

-200

-400

-600

-200 150100500-50-100-150 TIME (ps)

DATA RATE = 5Gbps,

INEQ_0 = INEQ_1 = 0, V

0EQ_0 = 0, OEQ_1 = 0, OEQ_2 = 0

600

400

200

0

VOLTAGE (mV)

-200

-400

-600

-200 150100500-50-100-150 TIME (ps)

= 200mV

IN

= 200mV

IN

P-P

,

MAX14950A toc03

,

MAX14950A toc06

�� Maxim Integrated Products 7

Single-Lane PCIe Equalizer/Redriver

Typical Operating Characteristics (continued)

(VCC = +3.3V, TA = +25NC, unless otherwise noted.)

DATA RATE = 5Gbps,

INEQ_0 = INEQ_1 = 0, V

0EQ_0 = 0, OEQ_1 = 0, OEQ_2 = 0

600

400

200

0

VOLTAGE (mV)

-200

-400

-600

-200 150100500-50-100-150 TIME (ps)

= 200mV

IN

P-P

,

MAX14950A toc07

600

400

200

VOLTAGE (mV)

-200

-400

-600

DATA RATE = 5Gbps,

INEQ_0 = INEQ_1 = 0, V

IN

0EQ_0 = 0, OEQ_1 = 0, OEQ_2 = 0

0

-200 150100500-50-100-150 TIME (ps)

= 200mV

P-P

,

MAX14950A toc08

MAX14950A

DATA RATE = 5Gbps,

= 500mV

V

IN

0EQ_0 = 0, OEQ_1 = 0, OEQ_2 = 0

600

400

200

0

VOLTAGE (mV)

-200

-400

-600

-200 150100500-50-100-150

P-P

INEQ_0 = 1, INEQ_1 = 0,

TIME (ps)

WITH 6in STRIP LINE,

MAX14950A toc09

DATA RATE = 5Gbps,

= 500mV

V

IN

P-P

INEQ_0 = 1, INEQ_1 = 0,

0EQ_0 = 0, OEQ_1 = 0, OEQ_2 = 0

600

400

200

0

VOLTAGE (mV)

-200

-400

-600

-200 150100500-50-100-150 TIME (ps)

WITH 6in STRIP LINE,

MAX14950A toc10

DATA RATE = 5Gbps,

= 500mV

V

IN

P-P

INEQ_0 = 1, INEQ_1 = 0,

0EQ_0 = 0, OEQ_1 = 0, OEQ_2 = 0

600

400

200

0

VOLTAGE (mV)

-200

-400

-600

-200 150100500-50-100-150 TIME (ps)

WITH 6in STRIP LINE,

MAX14950A toc11

V

IN

600

400

200

0

VOLTAGE (mV)

-200

-400

-600

-200 150100500-50-100-150

DATA RATE = 5Gbps,

= 500mV

WITH 6in STRIP LINE,

P-P

INEQ_0 = 1, INEQ_1 = 0,

0EQ_0 = OEQ_1 = 0, OEQ_2 = 0

TIME (ps)

MAX14950A toc12

�� Maxim Integrated Products 8

Single-Lane PCIe Equalizer/Redriver

Typical Operating Characteristics (continued)

(VCC = +3.3V, TA = +25NC, unless otherwise noted.)

MAX14950A

DATA RATE = 5Gbps,

OUTPUT AFTER 19in

INEQ_1 = 0, V

0EQ_0 = 1, OEQ_1 = 0, OEQ_2 = 0

300

200

100

0

VOLTAGE (mV)

-100

-200

-300

-200 150100500-50-100-150 TIME (ps)

DATA RATE = 5Gbps,

OUTPUT AFTER 19in

INEQ_1 = 0, V

0EQ_0 = 1, OEQ_1 = 0, OEQ_2 = 0

300

200

100

= 200mV

IN

= 200mV

IN

STRIP LINE,

,

P-P

STRIP LINE,

,

P-P

MAX14950A toc13

MAX14950A toc16

DATA RATE = 5Gbps,

OUTPUT AFTER 19in

INEQ_1 = 0, V

0EQ_0 = 1, OEQ_1 = 0, OEQ_2 = 0

300

200

100

0

VOLTAGE (mV)

-100

-200

-300

-200 150100500-50-100-150 TIME (ps)

DATA RATE = 5Gbps,

OUTPUT AFTER 19in

INEQ_1 = 0, V

0EQ_0 = 1, OEQ_1 = 0, OEQ_2 = 0

300

200

100

STRIP LINE,

= 200mV

IN

STRIP LINE,

= 200mV

IN

P-P

DATA RATE = 5Gbps,

OUTPUT AFTER 19in

,

INEQ_1 = 0, V

STRIP LINE,

= 200mV

IN

P-P

,

0EQ_0 = 1, OEQ_1 = 0, OEQ_2 = 0

250

200

MAX14950A toc14

150

100

50

0

-50

VOLTAGE (mV)

-100

-150

-200

-250

-200 150100500-50-100-150 TIME (ps)

MAX14950A toc15

DATA RATE = 5Gbps,

OUTPUT AFTER 19in

,

INEQ_1 = 0, V

STRIP LINE,

= 200mV

IN

P-P

,

0EQ_0 = 1, OEQ_1 = 0, OEQ_2 = 0

300

MAX14950A toc17

200

100

MAX14950A toc18

0

VOLTAGE (mV)

-100

-200

-300

-200 150100500-50-100-150

0

VOLTAGE (mV)

-100

-200

-300

-200 150100500-50-100-150 TIME (ps)

TIME (ps)

0

VOLTAGE (mV)

-100

-200

-300

-200 150100500-50-100-150 TIME (ps)

�� Maxim Integrated Products 9

Single-Lane PCIe Equalizer/Redriver

Typical Operating Characteristics (continued)

(VCC = +3.3V, TA = +25NC, unless otherwise noted.)

MAX14950A

DATA RATE = 5Gbps,

OUTPUT AFTER 19in

INEQ_1 = 0, V

0EQ_0 = 1, OEQ_1 = 0, OEQ_2 = 0

250

200

150

100

50

0

-50

VOLTAGE (mV)

-100

-150

-200

-250

-200 150100500-50-100-150 TIME (ps)

DATA RATE = 8Gbps,

INEQ_0 = INEQ_1 = 0, V

0EQ_0 = 0, OEQ_1 = 0, OEQ_2 = 0

600

400

200

0

VOLTAGE (mV)

-200

-400

-600

-100 -50 0 50 100 TIME (ps)

STRIP LINE,

= 200mV

IN

P-P

= 200mV

DATA RATE = 5Gbps,

OUTPUT AFTER 19in

,

INEQ_1 = 0, V

0EQ_0 = 1, OEQ_1 = 0, OEQ_2 = 0

500

400

MAX14950A toc19

300

200

100

0

-100

VOLTAGE (mV)

-200

-300

-400

-500

-200 150100500-50-100-150

DATA RATE = 8Gbps,

P-P

,

INEQ_0 = INEQ_1 = 0, V

0EQ_0 = 0, OEQ_1 = 0, OEQ_2 = 0

600

400

MAX14950A toc22

200

0

VOLTAGE (mV)

-200

-400

-600

-100 -50 0 50 100

= 200mV

IN

TIME (ps)

STRIP LINE,

P-P

= 200mV

IN

,

INEQ_0 = INEQ_1 = 0, V

= 200mV

IN

P-P

,

0EQ_0 = 0, OEQ_1 = 0, OEQ_2 = 0

DATA RATE = 8Gbps,

600

MAX14950A toc20

400

200

0

VOLTAGE (mV)

-200

-400

-600

-100 -50 0 50 100 TIME (ps)

MAX14950A toc21

DATA RATE = 8Gbps,

P-P

,

INEQ_0 = INEQ_1 = 0, V

= 200mV

IN

P-P

,

0EQ_0 = 0, OEQ_1 = 0, OEQ_2 = 0

600

MAX14950A toc23

400

200

0

VOLTAGE (mV)

-200

-400

-600

-100 -50 0 50 100 TIME (ps)

MAX14950A toc24

�� Maxim Integrated Products 10

Single-Lane PCIe Equalizer/Redriver

Typical Operating Characteristics (continued)

(VCC = +3.3V, TA = +25NC, unless otherwise noted.)

MAX14950A

DATA RATE = 8Gbps,

INEQ_0 = INEQ_1 = 0, V

0EQ_0 = 0, OEQ_1 = 0, OEQ_2 = 0

600

400

200

0

VOLTAGE (mV)

-200

-400

-600

-100 -50 0 50 100 TIME (ps)

DATA RATE = 8Gbps,

INEQ_0 = INEQ_1 = 0, V

0EQ_0 = 0, OEQ_1 = 0, OEQ_2 = 0

800

600

400

200

0

-200

VOLTAGE (mV)

-400

-600

-800

-100 -50 0 50 100 TIME (ps)

= 200mV

IN

= 200mV

IN

P-P

,

DATA RATE = 8Gbps,

INEQ_0 = INEQ_1 = 0, V

0EQ_0 = 0, OEQ_1 = 0, OEQ_2 = 0

600

MAX14950A toc25

400

200

0

VOLTAGE (mV)

-200

-400

-600

-100 -50 0 50 100 TIME (ps)

DATA RATE = 8Gbps, INEQ_0 = 1, INEQ_1 = 0,

= 500mV

V

IN

WITH 6in STRIPLINE,

P-P

0EQ_0 = OEQ_1 = 0, OEQ_2 = 0

600

400

MAX14950A toc28

200

0

VOLTAGE (mV)

-200

-400

-600

-100 -50 0 50 100 TIME (ps)

= 200mV

IN

P-P

,

MAX14950A toc26

MAX14950A toc29

DATA RATE = 8Gbps,

INEQ_0 = INEQ_1 = 0, V

= 200mV

IN

0EQ_0 = 0, OEQ_1 = 0, OEQ_2 = 0

600

400

200

0

VOLTAGE (mV)

-200

-400

-600

-100 -50 0 50 100 TIME (ps)

DATA RATE = 8Gbps, INEQ_0 = 1, INEQ_1 = 0,

= 500mV

V

IN

WITH 6in STRIPLINE,

P-P

0EQ_0 = OEQ_1 = 0, OEQ_2 = 0

600

400

200

0

VOLTAGE (mV)

-200

-400

-600

-100 -50 0 50 100 TIME (ps)

P-P

,

MAX14950A toc27

MAX14950A toc30

�� Maxim Integrated Products 11

Single-Lane PCIe Equalizer/Redriver

Typical Operating Characteristics (continued)

(VCC = +3.3V, TA = +25NC, unless otherwise noted.)

MAX14950A

DATA RATE = 8Gbps, INEQ_0 = 1, INEQ_1 = 0,

= 500mV

V

IN

WITH 6in STRIPLINE,

P-P

0EQ_0 = OEQ_1 = 0, OEQ_2 = 0

600

400

200

0

VOLTAGE (mV)

-200

-400

-600

-100 -50 0 50 100 TIME (ps)

DATA RATE = 8Gbps, OUTPUT AFTER

19in STRIPLINE, INEQ_0 = INEQ_1 = 0,

V

= 200mV

IN

P-P

,

0EQ_0 = 1, OEQ_1 = 0, OEQ_2 = 0

300

200

100

0

VOLTAGE (mV)

-100

-200

-300

-100 -50 0 50 100 TIME (ps)

DATA RATE = 8Gbps, INEQ_0 = 1, INEQ_1 = 0,

= 500mV

V

IN

WITH 6in STRIPLINE,

P-P

0EQ_0 = OEQ_1 = 0, OEQ_2 = 0

600

400

MAX14950A toc31

200

0

VOLTAGE (mV)

-200

-400

-600

-100 -50 0 50 100 TIME (ps)

DATA RATE = 8Gbps, OUTPUT AFTER

19in STRIPLINE, INEQ_0 = INEQ_1 = 0,

V

= 200mV

IN

0EQ_0 = 1, OEQ_1 = 0, OEQ_2 = 0

250

200

150

MAX14950A toc34

100

50

0

-100

VOLTAGE (mV)

-150

-100

-200

-250

-100 -50 0 50 100 TIME (ps)

P-P

DATA RATE = 8Gbps, OUTPUT AFTER

19in STRIPLINE, INEQ_0 = INEQ_1 = 0,

V

= 200mV

IN

P-P

,

0EQ_0 = 1, OEQ_1 = 0, OEQ_2 = 0

300

MAX14950A toc32

200

100

0

VOLTAGE (mV)

-100

-200

-300

-100 -50 0 50 100 TIME (ps)

MAX14950A toc33

DATA RATE = 8Gbps, OUTPUT AFTER

19in STRIPLINE, INEQ_0 = INEQ_1 = 0,

,

V

= 200mV

IN

P-P

,

0EQ_0 = 1, OEQ_1 = 0, OEQ_2 = 0

300

200

MAX14950A toc35

100

0

VOLTAGE (mV)

-100

-200

-300

-100 -50 0 50 100 TIME (ps)

MAX14590A toc36

�� Maxim Integrated Products 12

Single-Lane PCIe Equalizer/Redriver

Typical Operating Characteristics (continued)

(VCC = +3.3V, TA = +25NC, unless otherwise noted.)

MAX14950A

DATA RATE = 8Gbps, OUTPUT AFTER

19in STRIPLINE, INEQ_0 = INEQ_1 = 0,

V

= 200mV

IN

0EQ_0 = 1, OEQ_1 = 0, OEQ_2 = 0

250

200

150

100

50

0

-100

VOLTAGE (mV)

-150

-100

-200

-250

-100 -50 0 50 100 TIME (ps)

DATA RATE = 8Gbps, OUTPUT AFTER

19in STRIPLINE, INEQ_0 = INEQ_1 = 0,

V

= 200mV

IN

0EQ_0 = 1, OEQ_1 = 0, OEQ_2 = 0

250

200

150

100

50

0

-100

VOLTAGE (mV)

-150

-100

-200

-250

-100 -50 0 50 100 TIME (ps)

P-P

DATA RATE = 8Gbps, OUTPUT AFTER

19in STRIPLINE, INEQ_0 = INEQ_1 = 0,

,

V

= 200mV

IN

P-P

,

0EQ_0 = 1, OEQ_1 = 0, OEQ_2 = 0

300

MAX14950A toc37

200

100

0

VOLTAGE (mV)

-100

-200

-300

-100 -50 0 50 100 TIME (ps)

MAX14950A toc38

DATA RATE = 8Gbps, OUTPUT AFTER

19in STRIPLINE, INEQ_0 = INEQ_1 = 0,

,

V

= 200mV

IN

P-P

,

0EQ_0 = 1, OEQ_1 = 0, OEQ_2 = 0

500

400

MAX14950A toc39

300

200

100

0

-100

VOLTAGE (mV)

-200

-300

-400

-500

-100 -50 0 50 100 TIME (ps)

MAX14950A toc40

�� Maxim Integrated Products 13

MAX14950A

Single-Lane PCIe Equalizer/Redriver

Pin Configuration

TOP VIEW

OUTAM

RXDET

GND

INBP

INBM

GND

25

*EP

8 9 10

21

20 EIHBL

19

EILBLEILAL

18

V

CC

17

EIHBH

16

INEQB0

15

INEQB1

14

OEQB1

13

12

OEQB2

11

V

CC

OUTAP

GND

EIHAL

27282930 26 24 23 22

31

GND

32

V

33

CC

EIHAH

34

OEQA0

35

OEQA1

36

37OEQA2 OEQB0

38

INEQA0

39

INEQA1

40

V

CC

1 2

+

3

MAX14950A

4 5 6 7

GND

INAP

GNDENGND

INAM

TQFN

(5mm x 5mm)

*CONNECT EXPOSED PAD TO GND.

PIN NAME FUNCTION

1, 2, 5, 7, 10,

21, 24, 26,

GND Ground

29, 31

3 INAP Noninverting Input, Channel A 4 INAM Inverting Input, Channel A

6 EN

Enable Input. Drive EN low for standby mode. Drive EN high for normal mode. EN has a 375kI (typ) internal pulldown resistor.

8 OUTBP Noninverting Output, Channel B 9 OUTBM Inverting Output, Channel B

11, 18, 33,

40

12 OEQB2 13 OEQB1 14 OEQB0 15 INEQB1 16 INEQB0

V

CC

Power-Supply Input. Bypass VCC to GND with 0.1FF and 0.01FF capacitors in parallel as close as possible to the device.

Output Deemphasis Control MSB, Channel B. OEQB2 has a 375kI (typ) internal pulldown resistor. Output Deemphasis Bit 1, Channel B. OEQB1 has a 375kI (typ) internal pulldown resistor. Output Deemphasis Control LSB, Channel B. OEQB0 has a 375kI (typ) internal pulldown resistor. Input Equalization Control MSB, Channel B. INEQB1 has a 375kI (typ) internal pulldown resistor. Input Equalization Control LSB, Channel B. INEQB0 has a 375kI (typ) internal pulldown resistor.

OUTBP

OUTBM

GND

Pin Description

�� Maxim Integrated Products 14

Single-Lane PCIe Equalizer/Redriver

Pin Description (continued)

PIN NAME FUNCTION

17 EIHBH

19 EILBL

20 EIHBL

22 INBM Inverting Input, Channel B 23 INBP Noninverting Input, Channel B

25 RXDET

27 OUTAM Inverting Output, Channel A 28 OUTAP Noninverting Output, Channel A

30 EIHAL

32 EILAL

34 EIHAH

35 OEQA0 36 OEQA1 37 OEQA2 38 INEQA0 39 INEQA1

— EP

Electrical Idle High Threshold Increase Control Bit, Channel B. EIHBH has a 375kI (typ) internal pulldown resistor.

Electrical Idle Low Threshold Decrease Control Bit, Channel B. EILBL has a 375kI (typ) internal pulldown resistor.

Electrical Idle High Threshold Decrease Control Bit, Channel B. EIHBL has a 375kI (typ) internal pulldown resistor.

Receiver Detection Control Bit. Toggle RXDET to initiate receiver detection. RXDET has a 375kI (typ) internal pulldown resistor.

Electrical Idle High Threshold Decrease Control Bit, Channel A. EIHAL has a 375kI (typ) internal pulldown resistor.

Electrical Idle Low Threshold Decrease Control Bit, Channel A. EILAL has a 375kI (typ) internal pulldown resistor.

Electrical Idle High Threshold Increase Control Bit, Channel A. EIHAH has a 375kI (typ) internal pulldown resistor.

Output Deemphasis Control LSB, Channel A. OEQA0 has a 375kI (typ) internal pulldown resistor. Output Deemphasis Control Bit 1, Channel A. OEQA1 has a 375kI (typ) internal pulldown resistor. Output Deemphasis Control MSB, Channel A. OEQA2 has a 375kI (typ) internal pulldown resistor. Input Equalization Control LSB, Channel A. INEQA0 has a 375kI (typ) internal pulldown resistor. Input Equalization Control MSB, Channel A. INEQA1 has a 375kI (typ) internal pulldown resistor.

Exposed Pad. Internally connected to GND. Connect EP to a large ground plane to maximize thermal performance and ground conductivity to the device. Do not use EP as the only GND connection.

MAX14950A

�� Maxim Integrated Products 15

MAX14950A

Single-Lane PCIe Equalizer/Redriver

Functional Diagram

EN RXDET OEQ_2

INEQ_0 INEQ_1

IN_P

IN_M

RECEIVER DETECT

MANAGER

OUT_P

EQUALIZER

OUTPUT

ENABLE

R

HI

ELECTRICAL IDLE

DETECTOR

EIH_L EIH_HEIL_L

OEQ_0

EQUALIZER

OEQ_1

OUT_M

MAX14950A

Detailed Description

The MAX14950A dual equalizer/redriver supports Gen III (8GT/s), Gen II (5GT/s), and Gen I (2.5GT/s) PCIe data rates. The device contains two identical drivers with idle/receive detect on each lane and equalization/ deemphasis/preshoot to compensate for circuit board loss. Programmable input equalization circuitry reduces deterministic jitter, improving signal integrity. The device features programmable output deemphasis/preshoot, permitting optimal placement of key PCIe components and longer runs of stripline, microstrip, or cable.

�� Maxim Integrated Products 16

Programmable Input Equalization

Programmable input equalization for channel A is controlled by two bits: INEQA1 and INEQA0 and for channel B is controlled by two bits: INEQB1 and INEQB0 (Table 1.)

Table 1. Input Equalization

INEQ�1 INEQ�0 INPUT EQUALIZATION (dB)

0 0 3 0 1 5 1 0 7 1 1 9

MAX14950A

Single-Lane PCIe Equalizer/Redriver

Table 2. Output Deemphasis/Preshoot

OUTPUT

OEQ�2 OEQ�1 OEQ�0

0 0 0 0 0 0 1 3.5 0 1 0 6 0 1 1 6 1 0 0 3.5 1 0 1 6 1 1 0 9 1 1 1 91 Yes

1

Peak-to-peak swing is 1.0V.

2

Peak-to-peak swing is 1.2V.

3

Peak-to-peak swing is 0.9V.

DEEMPHASIS

RATIO (dB)

1

2

1

3

PRESHOOT

No No No

No Yes Yes Yes

Table 3. Receiver Detection Input Function

RXDET EN DESCRIPTION

X 0 Receiver detection is inactive

Following a rising edge of EN

signal, indefinite retry until a

X 1

Rising/Falling

Edge

X = Don’t care.

receiver is detected for at least

one channel. Retries stop a

few times after any channel is

detected.

1 Initiate receiver detection

Programmable Output Deemphasis

Programmable output deemphasis/preshoot for channel A is controlled by the three bits: OEQA2, OEQA1, OEQA0 and channel B is controlled by the three bits: OEQB2, OEQB1, OEQB0 (Table 2.)

Receiver Detection

The device features receiver detection on each channel. Upon initial power-up, if EN is high, receiver detection initializes. Receiver detection can also be initiated on a rising or falling edge of the RXDET input when EN is high. During this time, the part remains in low-power standby mode and the outputs are squelched, despite the logichigh state of EN. Until a channel has detected a receiver, the receiver detection repeats indefinitely on each channel. If a channel detects a receiver, the other channel is limited to a few retries. Upon receiver detection, input common-mode termination and electrical idle detection are enabled (Table 3.)

Electrical Idle Detection

The device features electrical idle detection to prevent unwanted noise from being redriven at the output. When the device detects the differential input has fallen below the electrical idle low threshold, it squelches the output. For differential input signals that are above the electrical idle high threshold, the device turns on the output and redrives the signal. Electrical idle threshold is set independently for each channel. Drive the EIHAL, EILAL, and EIHAH for channel A and drive EIHBL, EILBL, and EIHBH for channel B as shown in Table 4 to set the electrical idle high and low threshold limits. There is little variation in output common-mode voltage between electrical idle and redrive modes.

Table 4. Electrical Idle Detection Limits Threshold Setting

EIL�L EIH�H EIH�L THRESHOLD LOW LIMIT (typ) (mV) THRESHOLD HIGH LIMIT (typ) (mV)

0 0 0 118 120 0 0 1 88 90 0 1 0 148 150 0 1 1 Not Valid Not Valid 1 0 0 92 107 1 0 1 Not Valid Not Valid 1 1 0 125 135 1 1 1 Not Valid Not Valid

�� Maxim Integrated Products 17

MAX14950A

Single-Lane PCIe Equalizer/Redriver

Applications Information

Layout

Circuit board layout and design can significantly affect the performance of the device. Use good high-frequency design techniques, including minimizing ground inductance and using controlled-impedance transmission lines on data signals. Power-supply decoupling capacitors must be placed as close as possible to V connect V run receive and transmit on different layers to minimize crosstalk.

to a power plane. It is recommended to

CC

Exposed-Pad Package

The exposed-pad, 40-pin TQFN package incorporates features that provide a very low thermal resistance path for heat removal from the IC. The exposed pad on the device must be soldered to the circuit board ground plane for proper thermal performance. For more information on exposed-pad packages, refer to Maxim Application Note HFAN-08.1: Thermal Considerations of QFN and Other Exposed-Paddle Packages.

Power-Supply Sequencing

Caution: Do not exceed the absolute maximum ratings because stresses beyond the listed ratings could cause permanent damage to the device.

Proper power-supply sequencing is recommended for all devices. Always apply GND then V signals, especially if the signal is not current limited.

before applying

CC

. Always

CC

Ordering Information

PART TEMP RANGE PIN-PACKAGE

MAX14950ACTL+

+Denotes a lead(Pb)-free/RoHS-compliant package. *EP = Exposed pad.

0NC to +70NC

40 TQFN-EP*

Chip Information

PROCESS: BiCMOS

Package Information

For the latest package outline information and land patterns (footprints), 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 suffix character, but the drawing pertains to the package regardless of RoHS status.

PACKAGE

TYPE

40 TQFN-EP T4055+2

PACKAGE

CODE

OUTLINE

NO.

21-0140 90-0002

LAND

PATTERN NO.

�� Maxim Integrated Products 18

MAX14950A

Single-Lane PCIe Equalizer/Redriver

Revision History

REVISION

NUMBER

0 6/11 Initial release —

REVISION

DATE

DESCRIPTION

PAGES

CHANGED

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.

Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 19

©

2011 Maxim Integrated Products Maxim is a registered trademark of Maxim Integrated Products, Inc.

MAXIM MAX14950A Technical data

Specifications and Main Features

Frequently Asked Questions

User Manual

General Description

Applications

Benefits and Features

Typical Operating Circuit

ABSOLUTE MAXIMUM RATINGS

ELECTRICAL CHARACTERISTICS

Figure 1. Illustration of Output Deemphasis

Typical Operating Characteristics

Pin Configuration

Pin Description

Functional Diagram

Detailed Description

Programmable Input Equalization

Table 1. Input Equalization

Table 2. Output Deemphasis/Preshoot

Table 3. Receiver Detection Input Function

Programmable Output Deemphasis

Receiver Detection

Electrical Idle Detection

Table 4. Electrical Idle Detection Limits Threshold Setting

Applications Information

Layout

Exposed-Pad Package

Ordering Information

Chip Information

Package Information

Revision History