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General Description
The MAX9210/MAX9214/MAX9220/MAX9222 deserialize
three LVDS serial data inputs into 21 single-ended LVCMOS/LVTTL outputs. A parallel rate LVDS clock received
with the LVDS data streams provides timing for deserialization. The outputs have a separate supply, allowing
1.8V to 5V output logic levels.
The MAX9210/MAX9214/MAX9220/MAX9222 feature
programmable DC balance, which allows isolation
between a serializer and deserializer using AC-coupling.
Each deserializer decodes data transmitted by one of
MAX9209/MAX9213 serializers.
The MAX9210/MAX9214 have rising-edge output
strobes, and when DC balance is not programmed, are
compatible with non-DC-balanced 21-bit deserializers
such as the DS90CR216A and DS90CR218A. The
MAX9220/MAX9222 have falling-edge output strobes.
Two frequency versions and two DC-balance default conditions are available for maximum replacement flexibility
and compatibility with popular non-DC-balanced deserializers. The transition time of the single-ended outputs is
increased on the low-frequency version parts
(MAX9210/MAX9220) for reduced EMI. The LVDS inputs
meet IEC 61000-4-2 Level 4 ESD specification, ±15kV for
Air Discharge and ±8kV Contact Discharge.
The MAX9210/MAX9214/MAX9220/MAX9222 are available in a TSSOP package, and operate over the -40°C to
+85°C temperature range.
Applications
Automotive Navigation Systems
Automotive DVD Entertainment Systems
Digital Copiers
Laser Printers
Features
♦ Programmable DC Balance or Non-DC Balance
♦ DC Balance Allows AC-Coupling for Wider Input
Common-Mode Voltage Range
♦ As Low as 8MHz Operation (MAX9210/MAX9220)
♦ Falling-Edge Output Strobe (MAX9220/MAX9222)
♦ Slower Output Transitions for Reduced EMI
(MAX9210/MAX9220)
♦ High-Impedance Outputs when PWRDWN is Low
Allow Output Busing
♦ Pin Compatible with DS90CR216A/DS90CR218A
(MAX9210/MAX9214)
♦ Fail-Safe Inputs in Non-DC-Balanced Mode
♦ 5V Tolerant PWRDWN Input
♦ PLL Requires No External Components
♦ Up to 1.785Gbps Throughput
♦ Separate Output Supply Pins Allow Interface to
1.8V, 2.5V, 3.3V, and 5V Logic
♦ LVDS Inputs Meet IEC 61000-4-2 Level and ISO
10605 ESD Requirements
♦ LVDS Inputs Conform to ANSI TIA/EIA-644 LVDS
Standard
♦ Low-Profile 48-Lead TSSOP Package
♦ +3.3V Main Power Supply
♦ -40°C to +85°C Operating Temperature Range
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.
VCCto GND...........................................................-0.5V to +4.0V
V
CCO
to GND.........................................................-0.5V to +6.0V
RxIN_, RxCLK IN_ to GND ....................................-0.5V to +4.0V
PWRDWN to GND .................................................-0.5V to +6.0V
DCB/NC to GND.........................................-0.5V to (V
CC
+ 0.5V)
RxOUT_, RxCLK OUT to GND .................-0.5V to (V
The MAX9210/MAX9220 operate at a parallel clock frequency of 8MHz to 34MHz in DC-balanced mode and
10MHz to 40MHz in non-DC-balanced mode. The
MAX9214/MAX9222 operate at a parallel clock frequency
of 16MHz to 66MHz in DC-balanced mode and 20MHz to
85MHz in non-DC-balanced mode. The transition times of
the single-ended outputs are increased on the
MAX9210/MAX9220 for reduced EMI.
DC-balanced or non-DC-balanced operation is controlled by the DCB/NC pin (see Table 1 for DCB/NC
default settings and operating modes). In non-DC-balanced mode, each channel deserializes 7 bits every
cycle of the parallel clock. In DC-balanced mode, 9 bits
are deserialized every clock cycle (7 data bits + 2 DCbalance bits). The highest data rate in DC-balanced
mode for the MAX9214 and MAX9222 is 66MHz x 9 =
594Mbps. In non-DC-balanced mode, the maximum
data rate is 85MHz x 7 = 595Mbps.
DC Balance
Data coding by the MAX9209/MAX9213 serializers
(which are companion devices to the MAX9210/
MAX9214/MAX9220/MAX9222 deserializers) limits the
imbalance of ones and zeros transmitted on each channel. If +1 is assigned to each binary 1 transmitted and -1
is assigned to each binary 0 transmitted, the variation in
the running sum of assigned values is called the digital
sum variation (DSV). The maximum DSV for the data
channels is 10. At most, 10 more zeros than ones, or 10
more ones than zeros, are transmitted. The maximum
DSV for the clock channel is five. Limiting the DSV and
choosing the correct coupling capacitors maintains differential signal amplitude and reduces jitter due to
droop on AC-coupled links.
To obtain DC balance on the data channels, the serializer parallel data is inverted or not inverted, depending
on the sign of the digital sum at the word boundary.
Two complementary bits are appended to each group
of 7 parallel input data bits to indicate to the MAX9210/
MAX9214/MAX9220/MAX9222 deserializers whether
the data bits are inverted (see Figures 9 and 10). The
deserializer restores the original state of the parallel
data. The LVDS clock signal alternates duty cycles of
4/9 and 5/9, which maintain DC balance.
AC-Coupling Benefits
Bit errors experienced with DC-coupling can be eliminated by increasing the receiver common-mode voltage
range by AC-coupling. AC-coupling increases the common-mode voltage range of an LVDS receiver to nearly
Figure 9. Deserializer Serial Input in Non-DC-Balanced Mode
Figure 10. Deserializer Serial Input in DC-Balanced Mode
Figure 8. Power-Down Delay
PWRDWN
RxCLK IN
RxOUT_
RxCLK OUT
+
RxCLK IN
TxIN14TxIN15
RxIN2
TxIN7TxIN8
RxIN1
0.8V
RPDD
HIGH-Z
TxIN9TxIN13TxIN10TxIN11TxIN12
CYCLE N + 1CYCLE NCYCLE N - 1
TxIN14TxIN15TxIN16TxIN20TxIN17TxIN18TxIN19
TxIN7TxIN8
TxIN14TxIN15TxIN16TxIN20TxIN17TxIN18TxIN19
TxIN7TxIN8TxIN9TxIN13TxIN10TxIN11TxIN12
TxIN1
TxIN0
RxIN0
TxIN_ IS DATA FROM THE SERIALIZER.
TxIN2TxIN6TxIN3TxIN4TxIN5
+
RxCLK IN
DCB2DCA2
RxIN2
DCB1DCA1
RxIN1
DCA0
DCB0
RxIN0
TxIN_, DCA_, AND DCB_ ARE DATA FROM THE SERIALIZER.
the voltage rating of the capacitor. The typical LVDS driver output is 350mV centered on an offset voltage of
1.25V, making single-ended output voltages of 1.425V
and 1.075V. An LVDS receiver accepts signals from 0 to
2.4V, allowing approximately ±1V common-mode difference between the driver and receiver on a DC-coupled
link (2.4V - 1.425V = 0.975V and 1.075V - 0V = 1.075V).
Common-mode voltage differences may be due to
ground potential variation or common-mode noise. If
there is more than ±1V of difference, the receiver is not
guaranteed to read the input signal correctly and may
cause bit errors. AC-coupling filters low-frequency
ground shifts and common-mode noise and passes
high-frequency data. A common-mode voltage difference up to the voltage rating of the coupling capacitor
(minus half the differential swing) is tolerated. DC-balanced coding of the data is required to maintain the differential signal amplitude and limit jitter on an
AC-coupled link. A capacitor in series with each output
of the LVDS driver is sufficient for AC-coupling.
However, two capacitors—one at the serializer output
and one at the deserializer input—provide protection in
case either end of the cable is shorted to a high voltage.
Applications Information
Selection of AC-Coupling Capacitors
Voltage droop and the DSV of transmitted symbols
cause signal transitions to start from different voltage
levels. Because the transition time is finite, starting the
signal transition from different voltage levels causes
timing jitter. The time constant for an AC-coupled link
needs to be chosen to reduce droop and jitter to an
acceptable level.
The RC network for an AC-coupled link consists of the
LVDS receiver termination resistor (RT), the LVDS driver
output resistor (RO), and the series AC-coupling capacitors (C). The RC time constant for two equal-value
series capacitors is (C x (RT + RO))/2 (Figure 12). The
RC time constant for four equal-value series capacitors
is (C x (RT + RO))/4 (Figure 13).
RTis required to match the transmission line impedance (usually 100Ω) and ROis determined by the LVDS
driver design (the minimum differential output resistance of 78Ω for the MAX9209/MAX9213 serializers is
used in the following example). This leaves the capacitor selection to change the system time constant.
In the following example, the capacitor value for a
droop of 2% is calculated. Jitter due to this droop is
then calculated assuming a 1ns transition time:
C = - (2 x tBx DSV)/(ln (1 - D) x (RT+ RO)) (Eq 1)
where:
C = AC-coupling capacitor (F).
t
B
= bit time (s).
DSV = digital sum variation (integer).
ln = natural log.
D = droop (% of signal amplitude).
RT= termination resistor (Ω).
RO= output resistance (Ω).
Equation 1 is for two series capacitors (Figure 12). The
bit time (t
B
) is the period of the parallel clock divided by
9. The DSV is 10. See equation 3 for four series capacitors (Figure 13).
The capacitor for 2% maximum droop at 8MHz parallel
rate clock is:
C = - (2 x tBx DSV)/(ln (1 - D) x (RT+ RO))
C = - (2 x 13.9ns x 10)/(ln (1 - 0.02) x (100Ω + 78Ω))
C = 0.0773µF
Jitter due to droop is proportional to the droop and
transition time:
tJ= tTx D (Eq 2)
where:
t
J
= jitter (s).
tT= transition time (s) (0 to 100%).
D = droop (% of signal amplitude).
Jitter due to 2% droop and assumed 1ns transition time is:
tJ= 1ns x 0.02
tJ= 20ps
MAX9209
Figure 12. Two Capacitors per Link, AC-Coupled, DC-Balanced Mode
The transition time in a real system depends on the frequency response of the cable driven by the serializer.
The capacitor value decreases for a higher frequency
parallel clock and for higher levels of droop and jitter.
Use high-frequency, surface-mount ceramic capacitors.
Equation 1 altered for four series capacitors (Figure 13) is:
C = - (4 x tBx DSV)/(ln (1 - D) x (RT+ RO)) (Eq 3)
Fail-Safe
The MAX9210/MAX9214/MAX9220/MAX9222 have failsafe LVDS inputs in non-DC-balanced mode (Figure 1).
Fail-safe drives the outputs low when the corresponding LVDS input is open, undriven and shorted, or
undriven and parallel terminated. The fail-safe on the
LVDS clock input drives all outputs low. Fail-safe does
not operate in DC-balanced mode.
Input Bias and Frequency Detection
In DC-balanced mode, the inverting and noninverting
LVDS inputs are internally connected to +1.2V through
42kΩ (min) to provide biasing for AC-coupling (Figure 1).
A frequency-detection circuit on the clock input detects
when the input is not switching, or is switching at low
frequency. In this case, all outputs are driven low. To
prevent switching due to noise when the clock input is
not driven, bias the clock input to differential +15mV by
connecting a 10kΩ ±1% pullup resistor between the
noninverting input and VCC, and a 10kΩ ±1% pulldown
resistor between the inverting input and ground. These
bias resistors, along with the 100Ω ±1% tolerance termination resistor, provide +15mV of differential input.
However, the +15mV bias causes degradation of
RSKM proportional to the slew rate of the clock input.
For example, if the clock transitions 250mV in 500ps,
the slew rate of 0.5mV/ps reduces RSKM by 30ps.
Unused LVDS Data Inputs
In non-DC-balanced mode, leave unused LVDS data
inputs open. In non-DC balanced mode, the input failsafe circuit drives the corresponding outputs low and no
pullup or pulldown resistors are needed. In DC-balanced
mode, at each unused LVDS data input, pull the inverting
input up to V
CC
using a 10kΩ resistor, and pull the nonin-
verting input down to ground using a 10kΩ resistor. Do
not connect a termination resistor. The pullup and pulldown resistors drive the corresponding outputs low and
prevent switching due to noise.
Figure 13. Four Capacitors per Link, AC-Coupled, DC-Balanced Mode
TxIN
PWRDWN
TxCLK IN
MAX9209
MAX9213
7
(7 + 2):1
7
(7 + 2):1
7
(7 + 2):1
PLL
21:3 SERIALIZER3:21 DESERIALIZER
HIGH-FREQUENCY CERAMIC
SURFACE-MOUNT CAPACITORS
TxOUT
TxCLK OUT
RxIN
100Ω
100Ω
100Ω
100Ω
RxCLK IN
MAX9210
MAX9214
MAX9220
MAX9222
1:(9 - 2)
1:(9 - 2)
1:(9 - 2)
PLL
7
7
RxOUT
7
PWRDWN
RxCLK OUT
PWRDWN
Driving PWRDWN low puts the outputs in high impedance, stops the PLL, and reduces supply current to
50µA or less. Driving PWRDWN high drives the outputs
low until the PLL locks. The outputs of two deserializers
can be bused to form a 2:1 mux with the outputs controlled by PWRDWN. Wait 100ns between disabling one
deserializer (driving PWRDWN low) and enabling the
second one (driving PWRDWN high) to avoid contention of the bused outputs.
Input Clock and PLL Lock Time
There is no required timing sequence for the application or reapplication of the parallel rate clock (RxCLK
IN) relative to PWRDWN, or to a power-supply ramp for
proper PLL lock. The PLL lock time is set by an internal
counter. The maximum time to lock is 32,800 clock
periods. Power and clock should be stable to meet the
lock time specification. When the PLL is locking, the
outputs are low.
Power-Supply Bypassing
There are separate on-chip power domains for digital
circuits, outputs, PLL, and LVDS inputs. Bypass each
VCC, V
CCO
, PLL VCC, and LVDS VCCpin with high-frequency, surface-mount ceramic 0.1µF and 0.001µF
capacitors in parallel as close to the device as possible, with the smallest value capacitor closest to the
supply pin.
Cables and Connectors
Interconnect for LVDS typically has a differential impedance of 100Ω. Use cables and connectors that have
matched differential impedance to minimize impedance
discontinuities.
Twisted-pair and shielded twisted-pair cables offer
superior signal quality compared to ribbon cable and
tend to generate less EMI due to magnetic field canceling effects. Balanced cables pick up noise as common
mode, which is rejected by the LVDS receiver.
Board Layout
Keep the LVTTL/LVCMOS outputs and LVDS input signals separated to prevent crosstalk. A four-layer printedcircuit board (PCB) with separate layers for power,
ground, LVDS inputs, and digital signals is recommended.
ESD Protection
The MAX9210/MAX9214/MAX9220/MAX9222 ESD tolerance is rated for IEC 61000-4-2, Human Body Model and
ISO 10605 standards. IEC 61000-4-2 and ISO 10605
specify ESD tolerance for electronic systems. The IEC
61000-4-2 discharge components are CS= 150pF and
R
D
= 330Ω (Figure 14). For IEC 61000-4-2, the LVDS
inputs are rated for ±8kV Contact Discharge and ±15kV
Air Discharge. The Human Body Model discharge components are CS= 100pF and RD= 1.5kΩ (Figure 15). For
the Human Body Model, all pins are rated for ±5kV
Contact Discharge. The ISO 10605 discharge components are CS= 330pF and RD= 2kΩ (Figure 16). For ISO
10605, the LVDS inputs are rated for ±8kV Contact
Discharge and ±25kV Air Discharge.
5V Tolerant Input
PWRDWN is 5V tolerant and is internally pulled down to
GND. DCB/NC is not 5V tolerant. The input voltage
range for DCB/NC is nominally ground to VCC.
Normally, DCB/NC is connected to VCCor ground.
Figure 16. ISO 10605 Contact Discharge ESD Test Circuit
Skew margin (RSKM) is the time allowed for degradation of the serial data sampling setup and hold times by
sources other than the deserializer. The deserializer
sampling uncertainty is accounted for and does not
need to be subtracted from RSKM. The main outside
contributors of jitter and skew that subtract from RSKM
are interconnect intersymbol interference, serializer
pulse position uncertainty, and pair-to-pair path skew.
V
CCO
Output Supply and Power Dissipation
The outputs have a separate supply (V
CCO
) for interfacing
to systems with 1.8V to 5V nominal input logic levels. The
DC Electrical Characteristics table gives the maximum
supply current for V
CCO
= 3.6V with 8pF load at several
switching frequencies with all outputs switching in the
worst-case switching pattern. The approximate incremental supply current for V
CCO
other than 3.6V with the same
8pF load and worst-case pattern can be calculated using:
I
I
= CTVI 0.5fCx 21 (data outputs)
+ C
TVIfC
x 1 (clock output)
where:
II= incremental supply current.
CT= total internal (C
INT
) and external (CL) load capacitance.
V
I
= incremental supply voltage.
f
C
= output clock switching frequency.
The incremental current is added to (for V
CCO
> 3.6V)
or subtracted from (for V
CCO
< 3.6V) the DC Electrical
Characteristics table maximum supply current. The
internal output buffer capacitance is C
INT
= 6pF. The
worst-case pattern switching frequency of the data outputs is half the switching frequency of the output clock.
In the following example, the incremental supply current is
calculated for V
II= (14pF x 1.9V x 0.5 x 34MHz x 21) + (14pF x 1.9V x
34MHz).
II= 9.5mA + 0.9mA = 10.4mA.
The maximum supply current in DC-balanced mode for
V
CC
= V
CCO
= 3.6V at fC= 34MHz is 106mA (from the
DC Electrical Characteristics table). Add 10.4mA to get
the total approximate maximum supply current at V
CCO
= 5.5V and VCC= 3.6V.
If the output supply voltage is less than V
CCO
= 3.6V,
the reduced supply current can be calculated using the
same formula and method.
At high switching frequency, high supply voltage, and
high capacitive loading, power dissipation can exceed
the package power dissipation rating. Do not exceed
the maximum package power dissipation rating. See
the Absolute Maximum Ratings for maximum package
power dissipation capacity and temperature derating.
Rising- or Falling-Edge Output Strobe
The MAX9210/MAX9214 have a rising-edge output
strobe, which latches the parallel output data into the
next chip on the rising edge of RxCLK OUT. The
MAX9220/MAX9222 have a falling-edge output strobe,
which latches the parallel output data into the next chip
on the falling edge of RxCLK OUT. The deserializer output strobe polarity does not need to match the serializer input strobe polarity. A deserializer with rising or
falling edge output strobe can be driven by a serializer
with a rising edge input strobe.
(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information,
go to www.maxim-ic.com/packages
.)
N
MARKING
AAA23A
1
TOP VIEW
b
A2
e
D
SIDE VIEW
NOTES:
1. DIMENSIONS D & E ARE REFERENCE DATUMS AND DO NOT INCLUDE MOLD FLASH.
2. MOLD FLASH OR PROTRUSIONS NOT TO EXCEED 0.15MM ON D SIDE, AND 0.25MM ON E SIDE.
3. CONTROLLING DIMENSION: MILLIMETERS.
4. THIS PART IS COMPLIANT WITH JEDEC SPECIFICATION MO-153, VARIATIONS, ED (48L), EE (56L).
5. "N" REFERS TO NUMBER OF LEADS.
6. THE LEAD TIPS MUST LIE WITHIN A SPECIFIED ZONE. THIS TOLERANCE ZONE IS DEFINED BY TWO PARALLEL
PLANES. ONE PLANE IS THE SEATING PLANE, DATUM (-C-), THE OTHER PLANE IS AT THE SPECIFIED DISTANCE
FROM (-C-) IN THE DIRECTION INDICATED.
7. MARKING IS FOR PACKAGE ORIENTATION REFERENCE ONLY.
8. NUMBER OF LEADS SHOWN ARE FOR REFERENCE ONLY.
HE
BOTTOM VIEW
SEE DETAIL A
A1
A
SEATING
PLANE
0.25
()
L
C
L
END VIEW
PARTING
LINE
DETAIL A
c
WITH PLATING
BASE METAL
SECTION C-C
PACKAGE OUTLINE,
48 & 56L TSSOP, 6.1mm BODY
b
b1
21-0155
48L TSSOP.EPS
c1
c
1
C
1
MAX9210/MAX9214/MAX9220/MAX9222
Programmable DC-Balance
21-Bit Deserializers
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 ____________________ 17