General Description
The MAX4951 dual-channel buffer is designed to re-drive
serial-ATA (SATA) I and SATA II signals and is functional
up to 6.0Gbps for next-generation data rates. The
MAX4951 can be placed near an eSATA connector to
overcome board losses and produce an eSATA-compati-
ble signal level.
The MAX4951 preserves signal integrity at the receiver by
reestablishing full output levels, and can reduce the total
system jitter (TJ) by squaring up the signal. This device
features channel-independent digital boost 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 amplitude detection on the
inputs, and squelch on the corresponding outputs. Inputs
and outputs are all internally 50Ωterminated and must be
AC-coupled to the SATA controller IC and SATA device.
The MAX4951 operates from a single +3.3V (typ) sup-
ply 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 0°C to +70°C operat-
ing temperature range.
Applications
Servers
Desktop Computers
Notebook Computers
Docking Stations
Data Storage/Workstations
Features
oSingle +3.3V (typ) Supply Operation
oSupports SATA I (1.5Gbps) and SATA II (3.0Gbps)
oSupports up to 6.0Gbps for Next-Generation
Applications
oMeets SATA I, SATA II Input-/Output-Return Loss
Mask
oSupports eSATA Levels
oSupports SATA Out-of-Band (OOB) Signaling
oInternal Input/Output 50Ω
ΩTermination Resistors
oInline Signal Traces for Flow-Through Layout
oESD Protection on All Pins: ±5.5kV
oSpace-Saving, 4mm x 4mm, TQFN Package
MAX4951
SATA I/SATA II Bidirectional Re-Driver
________________________________________________________________
Maxim Integrated Products
1
Ordering Information
19-4178; Rev 1; 5/09
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.
+
Denotes a lead(Pb)-free/RoHS-compliant package.
*
EP = Exposed pad.
PART TEMP RANGE PIN-PACKAGE
MAX4951CTP+ 0°C to +70°C 20 TQFN-EP*
Pin Configuration
19
20
18
17
7
6
8
HAM
HBP
9
HAP
DAM
DBM
DBP
DAP
1 2
GND
45
15 14 12 11
GND
VCC
BA
BB
EN
VCC
MAX4951
GND GND
3
13
GND
16 10 VCC
VCC
TQFN
4mm x 4mm
TOP VIEW
HBM
*EP
*CONNECT EXPOSED PAD (EP) TO GND.
MAX4951
SATA I/SATA II Bidirectional Re-Driver
2 _______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS
(VCC = +3.0V to +3.6V, CL= 10nF, RL= 50Ω, TA= 0°C to +70°C, unless otherwise noted. Typical values are at VCC = +3.3V, TA= +25°C.)
(Note 3)
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.
(Voltages referenced to GND.)
VCC ........................................................................-0.3V to +4.0V
HAP, HAM, DBP, DBM, EN, BA, BB
(Note 1)...................................................-0.3V to (VCC + 0.3V)
Short-Circuit Output Current
(HBP, HBM, DAP, DAM) .................................................90mA
Continuous Current at Inputs
(HAP, HAM, DBP, DBM) ...............................................±30mA
Continuous Current
(EN, BA, BB) ...................................................................±5mA
Continuous Power Dissipation (TA= +70°C)
20-Pin TQFN (derate 25.6mW/°C above +70°C) ..... 2051mW
Junction-to-Case Thermal Resistance (θJC) (Note 2)
20-Pin TQFN...................................................................6°C/W
Junction-to-Ambient Thermal Resistance (θJA) (Note 2)
20-Pin TQFN.................................................................39°C/W
Operating Temperature Range...............................0°C to +70°C
Storage Temperature Range .............................-55°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°C
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
Operating Power-Supply Range VCC 3.0 3.6 V
BA = BB = VCC 90 125
Operating Supply Current ICC BA = BB = GND 70 100 mA
Standby Supply Current ISTBY EN = GND 7 10 mA
Single-Ended Input Resistance ZRX-SE-DC 40 Ω
Differential Input Resistance ZRX-DIFF-DC 85 100 115 Ω
Single-Ended Output Resistance ZTX-SE-DC 40 Ω
Differential Output Resistance ZTX-DIFF-DC 85 100 115 Ω
AC PERFORMANCE
f = 150MHz to 300MHz -29 -18
f = 300MHz to 600MHz -26 -14
f = 600MHz to 1200MHz -22 -10
f = 1.2GHz to 2.4GHz -18 -8
f = 2.4GHz to 3.0GHz -15 -3
Differential Input Return Loss
(Note 4) RLRX-DIFF
f = 3.0GHz to 5.0GHz -14 -1
dB
f = 150MHz to 300MHz -5
f = 300MHz to 600MHz -5
f = 600MHz to 1200MHz -2
f = 1.2GHz to 2.4GHz -2
f = 2.4GHz to 3.0GHz -2
Common-Mode Input Return Loss
(Note 4) RLRX-CM
f = 3.0GHz to 5.0GHz -1
dB
Note 1: All I/O pins are clamped by internal diodes.
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.
MAX4951
SATA I/SATA II Bidirectional Re-Driver
_______________________________________________________________________________________ 3
ELECTRICAL CHARACTERISTICS (continued)
(VCC = +3.0V to +3.6V, CL= 10nF, RL= 50Ω, TA= 0°C to +70°C, unless otherwise noted. Typical values are at VCC = +3.3V, TA= +25°C.)
(Note 3)
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
f = 150MHz to 300MHz -32 -14
f = 300MHz to 600MHz -26 -8
f = 600MHz to 1200MHz -21 -6
f = 1.2GHz to 2.4GHz -16 -6
f = 2.4GHz to 3.0GHz -15 -3
Differential Output Return Loss
(Note 4) RLTX-DIFF
f = 3.0GHz to 5.0GHz -13 -1
dB
f = 150MHz to 300MHz -8
f = 300MHz to 600MHz -5
f = 600MHz to 1200MHz -2
f = 1.2GHz to 2.4GHz -2
f = 2.4GHz to 3.0GHz -2
Common-Mode Output Return Loss
(Note 4) RLTX-CM
f = 3.0GHz to 5.0GHz -1
dB
Differential Input Signal Range VRX-DFF-PP SATA 1.5Gbps/3.0Gbps 220 1600 mVP-P
BA = BB = GND 450 525 650
Differential Output Swing VTX-DFF-PP f = 750MHz BA = BB = VCC 770 930 1144 mVP-P
Propagation Delay tPD 240 ps
Output Rise/Fall Time tR(Notes 4, 5) 60 ps
Deterministic Jitter TTX-DJ-DFF Up to 6.0Gbps (Notes 4, 6) 15 psP-P
Random Jitter TTX-RJ-DFF Up to 6.0Gbps (Notes 4, 6) 1.8 psRMS
OOB Detector Threshold VTH-OOB SATA OOB 50 150 mVP-P
OOB Output Startup/Shutdown Time tOOB (Note 7) 2 5 ns
BA = BB = GND -35
Crosstalk CTK f ≤ 1.5GHz BA = BB = VCC -30 dB
LOGIC INPUT
Input Logic-High VIH 1.4 V
Input Logic-Low VIL 0.6 V
Input Logic Hysteresis VHYST 0.1 V
ESD PROTECTION
All Pins Human Body Model ±5.5 kV
Note 3: All devices are 100% production tested at TA= +70°C. All temperature limits are guaranteed by design.
Note 4: Guaranteed by design.
Note 5: Rise and fall times are measured using 20% and 80% levels.
Note 6: DJ measured using K28.5 pattern; RJ measured using K28.7 pattern.
Note 7: Total time for OOB detection circuit to enable/squelch the output.
MAX4951
SATA I/SATA II Bidirectional Re-Driver
4 _______________________________________________________________________________________
Typical Operating Characteristics
(VCC = 3.3V, TA= +25°C, all eye diagrams measured using K28.5 pattern.)
BA = BB = GND EYE DIAGRAM
(VRX-DFF-PP = 220mVP-P, 1.5Gbps)
MAX4951 toc01
100mV/div
200ps/div
EYE DIAGRAM VOLTAGE (mV)
400200-400 -200 0
-300
-200
-100
0
100
200
300
-600 600
BA = BB = GND EYE DIAGRAM
(VRX-DFF-PP = 220mVP-P, 3.0Gbps)
MAX4951 toc02
100mV/div
100ps/div
EYE DIAGRAM VOLTAGE (mV)
200100-200 -100 0
-300
-200
-100
0
100
200
300
-300 300
BA = BB = GND EYE DIAGRAM
(VRX-DFF-PP = 220mVP-P, 6.0Gbps)
MAX4951 toc03
100mV/div
50ps/div
EYE DIAGRAM VOLTAGE (mV)
10050-100 -50 0
-300
-200
-100
0
100
200
300
-150 150
BA = BB = GND EYE DIAGRAM
(VRX-DFF-PP = 1600mVP-P, 1.5Gbps)
MAX4951 toc04
100mV/div
200ps/div
EYE DIAGRAM VOLTAGE (mV)
400200-400 -200 0
-300
-200
-100
0
100
200
300
-600 600
BA = BB = GND EYE DIAGRAM
(VRX-DFF-PP = 1600mVP-P, 3.0Gbps)
MAX4951 toc05
100mV/div
100ps/div
EYE DIAGRAM VOLTAGE (mV)
200100-200 -100 0
-300
-200
-100
0
100
200
300
-300 300
BA = BB = GND EYE DIAGRAM
(VRX-DFF-PP = 1600mVP-P, 6.0Gbps)
MAX4951 toc06
100mV/div
50ps/div
EYE DIAGRAM VOLTAGE (mV)
10050-100 -50 0
-300
-200
-100
0
100
200
300
-150 150
BA = BB = VCC EYE DIAGRAM
(VRX-DFF-PP = 220mVP-P, 1.5Gbps)
200ps/div
EYE DIAGRAM VOLTAGE (mV)
4002000-200-400
-400
-200
0
200
400
600
-600
-600 600
MAX4951 toc07
200mV/div
BA = BB = VCC EYE DIAGRAM
(VRX-DFF-PP = 220mVP-P, 6.0Gbps)
MAX4951 toc09
50ps/div
EYE DIAGRAM VOLTAGE (mV)
100500-50-100
-500
-400
-300
-200
-100
0
100
200
300
400
500
-150 150
200mV/div
MAX4951
SATA I/SATA II Bidirectional Re-Driver
_______________________________________________________________________________________ 5
Typical Operating Characteristics (continued)
(VCC = 3.3V, TA= +25°C, all eye diagrams measured using K28.5 pattern.)
BA = BB = VCC EYE DIAGRAM
(VRX-DFF-PP = 1600mVP-P, 1.5Gbps)
MAX4951 toc10
200ps/div
EYE DIAGRAM VOLTAGE (mV)
4002000-200-400-600 600
200mV/div
-400
-200
0
200
400
600
-600
BA = BB = VCC EYE DIAGRAM
(VRX-DFF-PP = 1600mVP-P, 3.0Gbps)
MAX4951 toc11
100ps/div
EYE DIAGRAM VOLTAGE (mV)
2001000-100-200-300 300
200mV/div
-400
-200
0
200
400
600
-600
BA = BB = VCC EYE DIAGRAM
(VRX-DFF-PP = 1600mVP-P, 6.0Gbps)
MAX4951 toc12
50ps/div
EYE DIAGRAM VOLTAGE (mV)
100500-50-100-150 150
200mV/div
-400
-200
0
200
400
600
-600
DIFFERENTIAL INPUT RETURN LOSS
vs. FREQUENCY
FREQUENCY (GHz)
DIFFERENTIAL INPUT RETURN LOSS (dB)
MAX4951 toc13
012345
-45
-40
-35
-30
-25
-20
-15
-10
-5
0
5
MAX4951
SATA MASK
DIFFERENTIAL OUTPUT RETURN LOSS
vs. FREQUENCY
FREQUENCY (GHz)
DIFFERENTIAL OUTPUT RETURN LOSS (dB)
MAX4951 toc14
012345
-45
-40
-35
-30
-25
-20
-15
-10
-5
0
5
MAX4951
SATA MASK
MAX4951
Detailed Description
The MAX4951 consists of two identical buffers that take
SATA input signals and return them to full output levels.
This device functions up to 6.0Gbps for next-generation
SATA applications.
Input/Output Terminations
Inputs and outputs are internally 50Ωterminated to VCC
(see the
Functional Diagram/Truth Table
) and must be
AC-coupled to the SATA controller IC and SATA device
for proper operation.
Out-Of-Band Logic
The MAX4951 provides full Out-Of-Band (OOB) signal
support through high-speed amplitude detection cir-
cuitry. SATA OOB differential input signals of 50mVP-P
or less are detected as OFF and not passed to the out-
put. 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 MAX4951. The time for the amplitude detection cir-
cuit to detect an inactive SATA OOB input and squelch
the associated output, or detect an active SATA OOB
input and enable the output, is less than 5ns.
Enable Input
The MAX4951 features an active-high enable input (EN).
EN has an internal pulldown resistor of 70kΩ(typ). When
EN is driven low or left unconnected, the MAX4951
enters low-power standby mode and the buffers are dis-
abled. Drive EN high for normal operation.
Output Boost Selection Inputs
The MAX4951 has two digital control logic inputs, BA
and BB. BA and BB have internal pulldown resistors of
70kΩ(typ). BA and BB control the boost level of their
corresponding buffers (see the
Functional Diagram/
Truth Table
). Drive BA or BB low or leave unconnected
for standard SATA output levels. Drive BA or BB high to
boost the output. The boosted output level compen-
sates for attenuation from longer trace-length cables or
to meet eSATA specifications.
Applications Information
Figure 3 shows a typical application circuit with the
MAX4951 used to drive an eSATA output. The diagram
assumes that the MAX4951 is close to the SATA host
controller. BB is set low to drive standard SATA levels
to the host, and BA is set high to drive eSATA levels to
the device. If the MAX4951 is further from the controller,
set BB high to compensate for attenuation.
SATA I/SATA II Bidirectional Re-Driver
6 _______________________________________________________________________________________
Pin Description
PIN NAME FUNCTION
1 HAP Noninverting Input from Host Channel A
2 HAM Inverting Input from Host Channel A
3, 13, 17,
18, 19 GND Ground
4 HBM Inverting Output to Host Channel B
5 HBP Noninverting Output to Host Channel B
6, 10, 16,
20 VCC Positive Supply Voltage Input. Bypass VCC to GND with 0.1µF and 0.001µF capacitors in parallel and as
close to the device as possible.
7EN
Active-High Enable Input. Drive EN low to put device in standby mode. Drive EN high for normal operation.
EN is internally pulled down.
8BB
Channel-B Boost Enable Input. Drive BB high to enable channel-B output boost. Drive BB low for standard
SATA output level. BB is internally pulled down.
9BA
Channel-A Boost Enable Input. Drive BA high to enable channel-A output boost. Drive BA low for standard
SATA output level. BA is internally pulled down.
11 DBP Noninverting Input from Device Channel B
12 DBM Inverting Input from Device Channel B
14 DAM Inverting Output to Device Channel A
15 DAP Noninverting Output to Device Channel A
—EP
Exposed Pad. Internally connected to GND. EP must be electrically connected to a ground plane for proper
thermal and electrical operation.
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
MAX4951 must be soldered to GND for proper thermal
and electrical 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
.
Layout
Use controlled-impedance transmission lines to inter-
face with the MAX4951 high-speed inputs and outputs.
Place power-supply decoupling capacitors as close as
possible to VCC.
ESD Protection
As with all Maxim devices, ESD-protection structures
are incorporated on all pins to protect against electro-
static discharges encountered during handling and
assembly. The MAX4951 is protected against ESD up
to ±5.5kV (Human Body Model) without damage. The
ESD structures withstand ±5.5kV in all states: normal
operation and powered down. After an ESD event, the
MAX4951 continues to function without latchup.
MAX4951
SATA I/SATA II Bidirectional Re-Driver
_______________________________________________________________________________________ 7
Functional Diagram/Truth Table
VCC
VCC
50Ω
50Ω
VCC
50Ω
50Ω
VCC
50Ω
50Ω
VCC
50Ω
50Ω
CONTROL LOGIC
MAX4951
DAP
HAP
DAM
HAM
DBM
HBM
DBP
HBP
BB ENBA
GND
X = Don’t Care
MAX4951
EN BA BB CHANNEL A CHANNEL B
0 X X Standby Standby
1 0 0 Standard SATA Standard SATA
1 1 0 Boost Standard SATA
1 0 1 Standard SATA Boost
1 1 1 Boost Boost
MAX4951
Human Body Model
The MAX4951 is characterized for ±5.5kV ESD protec-
tion using the Human Body Model (MIL-STD-883,
Method 3015). Figure 1 shows the Human Body Model
and Figure 2 shows the current waveform it generates
when discharged into a low impedance. This model
consists of a 100pF capacitor charged to the ESD volt-
age of interest that is then discharged into the device
through a 1.5kΩresistor.
Power-Supply Sequencing
Caution: Do not exceed the absolute maximum rat-
ings because stresses beyond the listed ratings
may 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.
SATA I/SATA II Bidirectional Re-Driver
8 _______________________________________________________________________________________
Figure 2. Human Body Current Waveform
IP 100%
90%
36.8%
tRL TIME
tDL
CURRENT WAVEFORM
PEAK-TO-PEAK RINGING
(NOT DRAWN TO SCALE)
Ir
10%
0
0
AMPS
CHARGE-CURRENT
LIMIT RESISTOR
DISCHARGE
RESISTANCE
STORAGE
CAPACITOR
Cs
100pF
RC
1MΩ
RD
1500Ω
HIGH-
VOLTAGE
DC
SOURCE
DEVICE
UNDER
TEST
Figure 1. Human Body ESD Test Model
MAX4951
SATA I/SATA II Bidirectional Re-Driver
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 _____________________
9
© 2009 Maxim Integrated Products Maxim is a registered trademark of Maxim Integrated Products, Inc.
MAX4951
EN
GPIO
+3.3V
0.001µF0.1µF
GNDBB
BA
+3.3V
SATA HOST
CONTROLLER
eSATA DEVICE CONNECTOR
Rx
Tx
10nF (X7R)
10nF (X7R)
10nF (X7R)
10nF (X7R)
10nF (X7R)
10nF (X7R)
10nF (X7R)
10nF (X7R)
HAP
HAM
HBM
HBP
DAP
DAM
DBM
DBP
Tx
Rx
Figure 3. Typical Application Circuit
Package Information
For the latest package outline information, go to
www.maxim-ic.com/packages.
PACKAGE TYPE PACKAGE CODE DOCUMENT NO.
20 TQFN-EP T2044-2 21-0139
Chip Information
PROCESS: BiCMOS
Revision History
REVISION
NUMBER
REVISION
DATE DESCRIPTION PAGES
CHANGED
0 6/08 Initial release —
1 5/09 Updated Features, Electrical Characteristics table, Applications Information
section, and added ESD Protection and Human Body Model sections. 1, 3, 6, 7, 8