_______________________________________________________________ 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.
SATA I/II/III Bidirectional Redriver
with Input Equalization and Preemphasis
MAX4951BE
19-5023; Rev 1; 11/10
General Description
The MAX4951BE dual-channel buffer is ideal to redrive
serial ATA (SATA) I, SATA II, and SATA III signals and
features high electrostatic discharge (ESD) Q8kV Human
Body Model (HBM) protection. The MAX4951BE can be
placed nearly anywhere on the motherboard to over-
come board losses and produce an eSATA-compatible
signal level. This device is SATA specification v.2.6 (gold
standard)-compliant, while overcom ing losses in the
PCB and eSATA connector.
The MAX4951BE features very low standby current for
power-sensitive applications. This device features hard-
ware SATA-drive cable detection, keeping the power low
in standby mode. The device also features an indepen-
dent channel, dynamic power-down mode where power
consumption is reduced when no input signal is present.
The MAX4951BE preserves signal integrity at the receiv-
er by reestablishing full output levels and can reduce
the total system jitter (TJ) by providing input equaliza-
tion. This device features channel-independent digital
preemphasis controls to drive SATA outputs over longer
trace lengths or to meet eSATA specifications. SATA
Out-Of-Band (OOB) signaling is supported using high-
speed OOB signal detection on the inputs and squelch
on the corresponding outputs. Inputs and outputs are all
internally 50I terminated and must be AC-coupled to the
SATA controller IC and SATA device.
The MAX4951BE operates from a single +3.3V (typ)
supply, and is available in a small, 4mm x 4mm TQFN
package with flow-through traces for ease of layout.
This device is specified over the 0NC to +70NC operating
temperature range.
Applications
Laptop Computers
Servers
Desktop Computers
Docking Stations
Data Storage/Workstations
Features
S Single +3.3V Supply Operation
S Low-Power, 500µA (typ) eSATA Cable Detect
S Drive Detection
S Dynamic Power Reduction
Reduced Power Consumption in Active Mode
S Fixed Input Equalization
Permits Longer Traces Leading to the Device
S Selectable Output Preemphasis
Improved Output Eye
S SATA I (1.5Gbps) and SATA II (3.0Gbps)
Compliant
S SATA III (6.0Gbps) Compliant
S Supports eSATA Output Levels
S Supports SATA OOB Signaling
S OOB Detection: 8ns (max)
S Internal Input/Output 50I Termination Resistors
S Inline Signal Traces for Flow-Through Layout
S Space-Saving, 4mm x 4mm TQFN Package with
Exposed Pad
S High ESD Protection on All Pins: ±8kV (HBM)
Ordering Information
+Denotes a lead(Pb)-free/RoHS-compliant package.
*EP = Exposed pad.
EVALUATION KIT
AVAILABLE
PART TEMP RANGE PIN-PACKAGE
MAX4951BECTP+ 0NC to +70NC 20 TQFN-EP*
SATA I/II/III Bidirectional Redriver
with Input Equalization and Preemphasis
MAX4951BE
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.
(All voltages referenced to GND unless otherwise noted.)
VCC .......................................................................-0.3V to +4.0V
AINP, AINM, BINP, BINM, EN, CAD,
PA, PB (Note 1) .......................................-0.3V to (VCC +0.4V)
Short-Circuit Output Current
(BOUTP, BOUTM, AOUTP, AOUTM) ........................... Q30mA
Continuous Current at Inputs
(AINP, AINM, BINP, BINM) ............................................ Q5mA
Continuous Power Dissipation (TA = +70NC)
TQFN (derate 25.6mW/NC above +70NC) ..................2051mW
ESD Protection on All Pins (HBM) .......................................Q8kV
Operating Temperature Range ............................. 0NC to +70NC
Storage Temperature Range ............................ -55NC to +150NC
Lead Temperature (soldering, 10s) ................................+300NC
Soldering Temperature (reflow) ......................................+260NC
ELECTRICAL CHARACTERISTICS
(VCC = +3.0V to +3.6V, CL = 12nF, RL = 50I, TA = 0NC to +70NC, unless otherwise noted. Typical values are at VCC = +3.3V, TA =
+25NC.) (Note 3)
ABSOLUTE MAXIMUM RATINGS
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.
PACKAGE THERMAL CHARACTERISTICS (Note 2)
TQFN
Junction-to-Ambient Thermal Resistance (qJA) ...........39°C/W
Junction-to-Case Thermal Resistance (qJC) ..................6°C/W
Note 1: All I/O pins are clamped by internal diodes.
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
Operating Power-Supply Range VCC 3.0 3.6 V
Operating Supply Current ICC
PA = PB = VCC;
D10.2 pattern, f = 1.5Gbps 77 92
mA
PA = PB = GND;
D10.2 pattern, f = 1.5Gbps 62 76
Average Supply Current in
Normal Operation
Duty cycle is 25%
active, 75% idle;
D10.2 pattern
Preemphasis on 30
mA
Preemphasis off 26
Standby Supply Current ISTBY EN = GND or CAD = VCC 500 750 FA
Dynamic Power-Down Current IDYNPD 14 20 mA
Single-Ended Input Resistance ZRX-SE-DC Single-ended to VCC (Note 4) 40 50 I
Differential Input Resistance ZRX-DIFF-
DC (Note 4) 85 100 115 I
Single-Ended Output Resistance ZTX-SE-DC Single-ended to VCC (Note 4) 40 50 I
Differential Output Resistance ZTX-DIFF-DC (Note 4) 85 100 115 I
AC PERFORMANCE
Differential Input Return Loss
(Notes 4, 5) RLRX-DIFF
f = 150MHz to 300MHz 18
dB
f = 300MHz to 600MHz 14
f = 600MHz to 1200MHz 10
f = 1.2GHz to 2.4GHz 8
f = 2.4GHz to 3.0GHz 3
f = 3.0GHz to 5.0GHz 1
SATA I/II/III Bidirectional Redriver
with Input Equalization and Preemphasis
MAX4951BE
_______________________________________________________________________________________ 3
ELECTRICAL CHARACTERISTICS (continued)
(VCC = +3.0V to +3.6V, CL = 12nF, RL = 50I, TA = 0NC to +70NC, unless otherwise noted. Typical values are at VCC = +3.3V, TA =
+25NC.) (Note 3)
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
Common-Mode Input Return
Loss (Notes 4, 5) RLRX-CM
f = 150MHz to 300MHz 5
dB
f = 300MHz to 600MHz 5
f = 600MHz to 1200MHz 2
f = 1.2GHz to 2.4GHz 1
f = 2.4GHz to 3.0GHz 1
f = 3.0GHz to 5.0GHz 1
Differential Output Return Loss
(Notes 4, 5) RLTX-DIFF
f = 150MHz to 300MHz 14
dB
f = 300MHz to 600MHz 8
f = 600MHz to 1200MHz 6
f = 1.2GHz to 2.4GHz 6
f = 2.4GHz to 3.0GHz 3
f = 3.0GHz to 5.0GHz 1
Common-Mode Output Return
Loss (Notes 4, 5) RLTX-CM
f = 150MHz to 300MHz 8
dB
f = 300MHz to 600MHz 5
f = 600MHz to 1200MHz 2
f = 1.2GHz to 2.4GHz 1
f = 2.4GHz to 3.0GHz 1
f = 3.0GHz to 5.0GHz 1
Common-Mode to Differential
Input Return Loss (Notes 4, 5)
RLRX-CM-
DM
f = 150MHz to 300MHz 30
dB
f = 300MHz to 600MHz 20
f = 600MHz to 1200MHz 10
f = 1.2GHz to 2.4GHz 10
f = 2.4GHz to 3.0GHz 4
f = 3.0GHz to 5.0GHz 4
Common-Mode to Differential
Output Return Loss (Notes 4, 5)
RLTX-CM-
DM
f = 150MHz to 300MHz 30
dB
f = 300MHz to 600MHz 30
f = 600MHz to 1200MHz 20
f = 1.2GHz to 2.4GHz 10
f = 2.4GHz to 3.0GHz 4
f = 3.0GHz to 5.0GHz 4
Differential Input Signal Range VRX-DFF-PP SATA I, SATA II (Note 4) 225 1600 mVP-P
Differential Output Swing VTX-DFF-PP f = 750MHz (Note 4) PA = PB = GND 425 525 625 mVP-P
Output Preemphasis TX-DFF-PP-
PEDB f = 750MHz PA = PB = VCC 2.8 dB
Input Equalization VRX-DFF-PP = 300mVP-P,
tIN,RISE/FALL = 20ps 2.7 dB
Preemphasis Time Period tPE f = 750MHz PA = PB = VCC 150 ps
Propagation Delay tPD 150 ps
SATA I/II/III Bidirectional Redriver
with Input Equalization and Preemphasis
MAX4951BE
4 ______________________________________________________________________________________
ELECTRICAL CHARACTERISTICS (continued)
(VCC = +3.0V to +3.6V, CL = 12nF, RL = 50I, TA = 0NC to +70NC, unless otherwise noted. Typical values are at VCC = +3.3V, TA =
+25NC.) (Note 3)
Note 3: All devices are 100% production tested at TA = +70°C. All temperature limits are guaranteed by design.
Note 4: This specification meets SATA v.2.6, gold standard.
Note 5: Guaranteed by design.
Note 6: Rise and fall times are measured using 20% and 80% levels.
Note 7: For SATA 2.0, refer to SATA 2.6-Gold Specification, page 111, Figure 191.
Note 8: For SATA 3.0, refer to SATA Revision 3.0 Release Candidate, page 222, Figure 124.
Note 9: DJ measured using a K28.5 pattern; RJ measured using a D10.2 pattern.
Note 10: Total time for OOB detection circuit to enable/squelch the output.
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
Output Rise/Fall Time
(Notes 5, 6) tR, tF
PA = PB = GND
SATA I/II (Note 7) 67 130
ps
PA = PB = GND
SATA III (Note 8) 40 68
Deterministic Jitter (Notes 5, 9) tTX-DJ-DD PA = PB = GND 20 psP-P
Random Jitter (Notes 5, 9) tTX-RJ-DD PA = PB = GND 1.5 psRMS
OOB Detector Threshold SATA OOB pattern, f = 750MHz 50 150 mVP-P
OOB Output Startup/Shutdown
Time (Note 10) 4 8 ns
OOB Differential-Offset Delta rVOOB,DFF Difference between OOB and active-mode
output offset -120 120 mV
OOB Common-Mode Delta rVOOB,CM Difference between OOB and active com-
mon-mode voltage -15 +15 mV
OOB Output Disable VOOB,OUT VIN < 50mVP-P, output voltage in squelch 30 mVP-P
LOGIC INPUT
Input Logic-High VIH 1.4 V
Input Logic-Low VIL 0.6 V
Input Logic Hysteresis VHYST 0.1 V
Input Pullup Resistance RPU Pin: CAD 200 330 kI
Input Pulldown Resistance RPD Pins: EN, PA, PB 200 330 kI
ESD PROTECTION
All Pins HBM Q8kV
SATA I/II/III Bidirectional Redriver
with Input Equalization and Preemphasis
MAX4951BE
_______________________________________________________________________________________ 5
Typical Operating Characteristics
(TA = +25°C, unless otherwise noted.)
VIN = 220mVP-P, 6.0Gbps, PA = 1, PB = 1
50ps/div
EYE DIAGRAM VOLTAGE (200mV/div)
100500-50-100
-400
-200
0
200
400
-150 150
MAX4951BE toc09
VIN = 220mVP-P, 3.0Gbps, PA = 1, PB = 1
100ps/div
EYE DIAGRAM VOLTAGE (200mV/div)
2001000-100-200
-400
-200
0
200
400
-300 300
MAX4951BE toc08
VIN = 220mVP-P, 1.5Gbps, PA = 1, PB = 1
200ps/div
EYE DIAGRAM VOLTAGE (200mV/div)
4002000-200-400
-400
-200
0
200
400
-600 600
MAX4951BE toc07
VIN = 1600mVP-P, 6.0Gbps, PA = 0, PB = 0
50ps/div
EYE DIAGRAM VOLTAGE (200mV/div)
100500-50-100
-200
0
200
-150 150
MAX4951BE toc06
VIN = 1600mVP-P, 3.0Gbps, PA = 0, PB = 0
100ps/div
EYE DIAGRAM VOLTAGE (200mV/div)
2001000-100-200
-200
0
200
-300 300
MAX4951BE toc05
VIN = 1600mVP-P, 1.5Gbps, PA = 0, PB = 0
200ps/div
EYE DIAGRAM VOLTAGE (200mV/div)
4002000-200-400
-200
0
200
-600 600
MAX4951BE toc04
VIN = 220mVP-P, 6.0Gbps, PA = 0, PB = 0
50ps/div
EYE DIAGRAM VOLTAGE (200mV/div)
100500-50-100
-200
0
200
-150 150
MAX4951BE toc03
VIN = 220mVP-P, 3.0Gbps, PA = 0, PB = 0
100ps/div
EYE DIAGRAM VOLTAGE (200mV/div)
2001000-100-200
-200
0
200
-300 300
MAX4951BE toc02
VIN = 220mVP-P, 1.5Gbps, PA = 0, PB = 0
200ps/div
EYE DIAGRAM VOLTAGE (200mV/div)
4002000-200-400
-200
0
200
-600 600
MAX4951BE toc01
SATA I/II/III Bidirectional Redriver
with Input Equalization and Preemphasis
MAX4951BE
6 ______________________________________________________________________________________
Typical Operating Characteristics (continued)
(TA = +25°C, unless otherwise noted.)
COMMON-MODE TO DIFFERENTIAL OUTPUT
RETURN LOSS vs. FREQUENCY
MAX4951BE toc18
FREQUENCY (GHz)
MAGNITUDE (dB)
431 2
-60
-70
-50
-40
-30
-20
-10
0
-80
0 5
MASK
COMMON-MODE TO DIFFERENTIAL INPUT
RETURN LOSS vs. FREQUENCY
MAX4951BE toc17
FREQUENCY (GHz)
MAGNITUDE (dB)
431 2
-60
-50
-40
-30
-20
-10
0
-70
0 5
MASK
COMMON-MODE OUTPUT RETURN LOSS
vs. FREQUENCY
MAX4951BE toc16
FREQUENCY (GHz)
MAGNITUDE (dB)
431 2
-35
-40
-30
-25
-20
-15
-10
-5
0
-45
0 5
MASK
COMMON-MODE INPUT RETURN LOSS
vs. FREQUENCY
MAX4951BE toc15
FREQUENCY (GHz)
MAGNITUDE (dB)
431 2
-50
-40
-30
-20
-10
0
-60
0 5
MASK
DIFFERENTIAL OUTPUT RETURN LOSS
vs. FREQUENCY
MAX4951BE toc14
FREQUENCY (GHz)
MAGNITUDE (dB)
431 2
-30
-25
-20
-15
-10
-5
0
-35
0 5
MASK
DIFFERENTIAL INPUT RETURN LOSS
vs. FREQUENCY
MAX4951BE toc13
FREQUENCY (GHz)
MAGNITUDE (dB)
431 2
-35
-30
-25
-20
-10
-15
-5
0
-40
0 5
MASK
VIN = 1600mVP-P, 6.0Gbps, PA = 1, PB = 1
50ps/div
EYE DIAGRAM VOLTAGE (200mV/div)
100500-50-100
-400
-200
0
200
400
-150 150
MAX4951BE toc12
VIN = 1600mVP-P, 3.0Gbps, PA = 1, PB = 1
100ps/div
EYE DIAGRAM VOLTAGE (200mV/div)
2001000-100-200
-400
-200
0
200
400
-300 300
MAX4951BE toc11
VIN = 1600mVP-P, 1.5Gbps, PA = 1, PB = 1
200ps/div
EYE DIAGRAM VOLTAGE (200mV/div)
4002000-200-400
-400
-200
0
200
400
-600 600
MAX4951BE toc10
SATA I/II/III Bidirectional Redriver
with Input Equalization and Preemphasis
MAX4951BE
_______________________________________________________________________________________ 7
Typical Operating Characteristics (continued)
(TA = +25°C, unless otherwise noted.)
EYE HEIGHT vs. OUTPUT LENGTH,
PA = 1, PB = 1 (7.5in OF INPUT TRACE)
MAX4951BE toc24
LENGTH (in)
EYE HEIGHT (mV)
252015105
50
100
150
200
250
300
350
400
450
500
0
0 30
VIN = 1VP-P
6Gbps,
NONTRANSITION BITS
3Gbps,
NONTRANSITION BITS
6Gbps,
TRANSITION BITS
3Gbps,
TRANSITION BITS
DETERMINISTIC JITTER vs. OUTPUT LENGTH,
PA = 1, PB = 1
MAX4951BE toc23
LENGTH (in)
DETERMINISTIC JITTER (psP-P)
252015105
5
10
15
20
25
30
35
40
45
0
0 30
VIN = 1VP-P, 7.5in OF INPUT TRACE
3Gbps
6Gbps
EYE HEIGHT vs. OUTPUT LENGTH,
PA = 0, PB = 0 (7.5in OF INPUT TRACE)
MAX4951BE toc22
LENGTH (in)
EYE HEIGHT (mV)
252015105
50
100
150
200
250
300
350
400
450
500
0
0 30
VIN = 1VP-P
6Gbps,
TRANSITION BITS
6Gbps,
NONTRANSITION BITS
3Gbps,
NONTRANSITION BITS
3Gbps,
TRANSITION BITS
DETERMINISTIC JITTER vs. OUTPUT LENGTH,
PA = 0, PB = 0
MAX4951BE toc21
LENGTH (in)
DETERMINISTIC JITTER (psP-P)
252015105
20
40
60
80
100
120
140
0
0 30
3Gbps
6Gbps
VIN = 1VP-P, 7.5in OF INPUT TRACE
EYE HEIGHT vs. INPUT LENGTH,
PA = 0, PB = 0
MAX4951BE toc20
LENGTH (in)
EYE HEIGHT (mV)
5040302010
100
200
300
400
500
600
0
0 60
VIN = 1VP-P 3Gbps, NONTRANSITION BITS
6Gbps,
NONTRANSITION BITS
6Gbps,
TRANSITION BITS 3Gbps,
TRANSITION BITS
DETERMINISTIC JITTER vs. INPUT LENGTH,
PA = 0, PB = 0
MAX4951BE toc19
LENGTH (in)
DETERMINISTIC JITTER (psP-P)
5040302010
50
100
150
200
250
300
0
0 60
VIN = 1VP-P
3Gbps
6Gbps
SATA I/II/III Bidirectional Redriver
with Input Equalization and Preemphasis
MAX4951BE
8 ______________________________________________________________________________________
Pin Configuration
Pin Description
19
20
18
17
7
6
8
AINM
BOUTP
9
AINP
AOUTM
BINM
BINP
AOUTP
1 2
CAD
4 5
15 14 12 11
GND
VCC
PA
PB
EN
+VCC
GND GND
3
13
GND
16 10 VCC
VCC
TQFN
(4mm × 4mm)
TOP VIEW
BOUTM
*EP
*CONNECT EXPOSED PAD (EP) TO GND.
MAX4951BE
PIN NAME FUNCTION
1 AINP Noninverting Input from Host Channel A
2 AINM Inverting Input from Host Channel A
3, 13, 17, 19 GND Ground
4 BOUTM Inverting Output to Host Channel B
5 BOUTP Noninverting Output to Host Channel B
6, 10, 16, 20 VCC Positive Supply Voltage Input. Bypass VCC to GND with 1FF and 0.01FF capacitors in parallel as
close to the device as possible.
7 EN Active-High Enable Input. Drive EN low to put the device in standby mode. Drive EN high for nor-
mal operation. EN is internally pulled down with a 330kW (typ) resistor.
8 PB Channel B Preemphasis Enable Input. Drive PB high to enable channel B output preemphasis. Drive
PB low for standard SATA output level. PB is internally pulled down with a 330kW (typ) resistor.
9 PA Channel A Preemphasis Enable Input. Drive PA high to enable channel A output preemphasis. Drive
PA low for standard SATA output level. PA is internally pulled down with a 330kW (typ) resistor.
11 BINP Noninverting Input from Device Channel B
12 BINM Inverting Input from Device Channel B
14 AOUTM Inverting Output to Device Channel A
15 AOUTP Noninverting Output to Device Channel A
18 CAD Active-Low Cable-Detect Input. Drive CAD high to put the device in standby mode. Drive CAD low
for normal operation. CAD is internally pulled up with a 330kI (typ) resistor.
— EP Exposed Pad. Internally connected to GND. EP must be electrically connected to a ground plane
for proper thermal and electrical operation.
SATA I/II/III Bidirectional Redriver
with Input Equalization and Preemphasis
MAX4951BE
_______________________________________________________________________________________ 9
Detailed Description
The MAX4951BE consists of two identical buffers that
take SATA input signals and return them to full output
levels while withstanding high ESD Q8kV (HBM) protec-
tion. This device meets SATA I/II specifications and can
meet SATA III specifications.
Input/Output Terminations
Inputs and outputs are internally 50I terminated to VCC
(see the Functional Diagram/Truth Table) and must be
AC-coupled to the SATA controller IC and SATA device
for proper operation.
Functional Diagram/Truth Table
Note: PA, PB, EN are internally pulled down to GND by 330k
W
resistors. CAD is internally pulled up to
VCC by a 330k
W
resistor.
X = Don’t care.
VCC
VCC
50Ω50Ω
VCC
50Ω50Ω
VCC
50Ω50Ω
VCC
50Ω50Ω
CONTROL LOGIC
AOUTP
AINP
AOUTM
AINM
BINM
BOUTM
BINP
BOUTP
PB EN CADPA
GND
MAX4951BE
EN CAD STATUS
0 0 Low-Power Standby
0 1 Low-Power Standby
1 0 Active
1 1 Low-Power Standby
EN PA PB CHANNEL A CHANNEL B
0 X X Standby Standby
1 0 0 Standard SATA Standard SATA
1 1 0 Preemphasis Standard SATA
1 0 1 Standard SATA Preemphasis
1 1 1 Preemphasis Preemphasis
SATA I/II/III Bidirectional Redriver
with Input Equalization and Preemphasis
MAX4951BE
10 _____________________________________________________________________________________
OOB Signal Detection
The MAX4951BE provides full OOB signal support
through high-speed, OOB-detection circuitry. SATA
OOB differential input signals of 50mVP-P or less are
detected as OFF and are not passed to the output. This
prevents the system from responding to unwanted noise.
SATA OOB differential input signals of 150mVP-P or more
are detected as on and passed to the output. This allows
OOB signals to transmit through the MAX4951BE. The
time for the OOB-detection circuit to detect an inactive
SATA OOB input and squelch the associated output,
or to detect an active SATA OOB input and enable the
output, is less than 4ns (typ).
Enable Input
The MAX4951BE features an active-high enable input
(EN). EN has an internal pulldown resistor of 330kI
(typ). When EN is driven low or left unconnected, the
MAX4951BE enters low-power standby mode and the
buffers are disabled, reducing the supply current to
500FA (typ). Drive EN high for normal operation.
Cable-Detect Input
The MAX4951BE features an active-low, cable-detect
input (CAD). CAD has an internal pullup resistor of
330kI (typ). When CAD is driven high or left uncon-
nected, the MAX4951BE enters low-power standby
mode and the buffers are disabled, reducing supply
current to 500FA (typ). This signal is normally driven low
by inserting an eSATA cable into a properly wired socket
(see Figure 3). If the cable-detect feature is not desired,
simply ground this pin.
Dynamic Power-Down Mode
The MAX4951BE features a dynamic power-down mode
where the device shuts down the major power consump-
tion circuitry. The MAX4951BE detects whether the input
signal does not exist for a 4Fs (typ) duration. Normal
power and normal operation resume when a signal
above the OOB-threshold level is detected at the input.
This function is implemented separately for both chan-
nels.
Output Preemphasis Selection Inputs
The MAX4951BE has two preemphasis-control logic
inputs, PA and PB. PA and PB have internal pulldown
resistors of 330kI (typ). PA and PB enable preemphasis
to the outputs of their corresponding buffers (see the
Functional Diagram/Truth Table). Drive PA or PB low
or leave unconnected for standard SATA output levels.
Drive PA or PB high to provide preemphasis to the out-
put. The preemphasis output signal compensates for
attenuation from longer trace lengths or to meet eSATA
specifications.
ESD Protection
As with all Maxim devices, ESD protection structures are
incorporated on all pins to protect against electrostatic
discharges encountered during handling and assembly.
The MAX4951BE is protected against ESD Q8kV (HBM).
The ESD struc tures withstand Q8kV in normal opera-
tion and powered down states. After an ESD event, the
MAX4951BE continues to function without latchup.
HBM
The MAX4951BE is characterized for Q8kV ESD pro-
tection using the HBM (MIL-STD-883, Method 3015).
Figure 1 shows the HBM and Figure 2 shows the cur-
rent waveform it generates when discharged into a
low-impedance state. This model con sists of a 100pF
capacitor charged to the ESD voltage of interest that is
then discharged into the device through a 1.5kI resistor.
Figure 1. Human Body ESD Test Model Figure 2. Human Body Current Waveform
CHARGE-CURRENT
LIMIT RESISTOR
DISCHARGE
RESISTANCE
STORAGE
CAPACITOR
CS
100pF
RC
1MΩ
RD
1500Ω
HIGH-
VOLTAGE
DC
SOURCE
DEVICE
UNDER
TEST
IP 100%
90%
36.8%
tRL TIME
tDL
CURRENT WAVEFORM
PEAK-TO-PEAK RINGING
(NOT DRAWN TO SCALE)
Ir
10%
0
0
AMPS
SATA I/II/III Bidirectional Redriver
with Input Equalization and Preemphasis
MAX4951BE
______________________________________________________________________________________ 11
Applications Information
Figure 3 shows a typical application with the MAX4951BE
used to drive an eSATA output. The diagram assumes
that the MAX4951BE is close to the SATA host controller.
PB is set low to drive standard SATA levels to the host,
and PA is set high to drive eSATA levels to the device.
If the MAX4951BE is further from the controller, set PB
high to compensate for attenuation. The MAX4951BE is
backward-pin-compatible with MAX4951 (see Figure 4).
Exposed-Pad Package
The exposed-pad, 20-pin TQFN package incorporates
features that provide a very low thermal resistance path
for heat removal from the IC. The exposed pad on the
MAX4951BE must be soldered to GND for proper ther-
mal and electrical performance. For more information on
exposed-pad packages, refer to Application Note 862:
HFAN-08.1: Thermal Considerations of QFN and Other
Exposed-Paddle Packages.
Layout
Use controlled-impedance transmission lines to interface
with the MAX4951BE high-speed inputs and outputs.
Place power-supply decoupling capacitors as close as
possible to VCC pin.
Power-Supply Sequencing
Caution: Do not exceed the absolute maximum rat-
ings because stresses beyond the listed ratings can
cause permanent damage to the device.
Proper power-supply sequencing is recommended for
all devices. Always apply VCC before applying signals,
especially if the signal is not current limited.
Figure 3. Typical Application Circuit for MAX4951BE Driving an eSATA Output
EN
GPIO
+3.3V
0.01µF1µF
GNDPB
VCC
PA
VCC
SATA HOST
CONTROLLER
eSATA
DEVICE
CONNECTOR
Rx
1
4
5
6
7 OR 1*
*PINS 1 AND 7 CAN BE INTERCHANGED DEPENDING ON THE LAYOUT.
2
3
Tx
10nF (X7R)
10nF (X7R)
10nF (X7R)
10nF (X7R)
10nF (X7R)
10nF (X7R)
10nF (X7R)
10nF (X7R)
AINP
AINM
BOUTM
BOUTP
AOUTP
AOUTM
BINM
BINP
CAD
Tx
Rx
MAX4951BE
SATA I/II/III Bidirectional Redriver
with Input Equalization and Preemphasis
MAX4951BE
12 _____________________________________________________________________________________
Chip Information
PROCESS: BiCMOS
Package Information
For the latest package outline information and land patterns,
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.
Figure 4. Typical Application Circuit for Backward Pin Compatibility with the MAX4951
+3.3V
0.01µF
*PINS 1 AND 7 CAN BE INTERCHANGED DEPENDING ON THE LAYOUT.
1µF
VCC
SATA HOST
CONTROLLER
eSATA
DEVICE
CONNECTOR
Rx
1
4
5
6
7 OR 1*
2
3
Tx
10nF (X7R)
10nF (X7R)
10nF (X7R)
10nF (X7R)
10nF (X7R)
10nF (X7R)
10nF (X7R)
10nF (X7R)
AINP
AINM
BOUTM
BOUTP
AOUTP
AOUTM
BINM
BINP
Tx
Rx
MAX4951BE
EN
GPIO
GNDPBPA
VCC
CAD
PACKAGE
TYPE
PACKAGE
CODE
OUTLINE
NO.
LAND
PATTERN NO.
20 TQFN-EP T2044+2 21-0139 90-0036
SATA I/II/III Bidirectional Redriver
with Input Equalization and Preemphasis
MAX4951BE
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 13
© 2010 Maxim Integrated Products Maxim is a registered trademark of Maxim Integrated Products, Inc.
Revision History
REVISION
NUMBER
REVISION
DATE DESCRIPTION PAGES
CHANGED
0 10/09 Initial release —
1 11/10 Deleted the “Meets SATA I, II Input/Output-Return Loss Mask” feature from the
Features section, deleted the “Top Mark” column from the Ordering Information 1
