MAXIM MAX3690

19-4774; Rev 1; 4/99
+3.3V, 622Mbps, SDH/SONET 8:1 Serializer
with Clock Synthesis and TTL Inputs
____________________________Features
The MAX3690 serializer is ideal for converting 8-bitwide, 77Mbps parallel data to 622Mbps serial data in
ATM and SDH/SONET applications. Operating from a
single +3.3V supply, this device accepts TTL clock and
data inputs, and delivers a 3.3V differential PECL serialdata output. A fully integrated PLL synthesizes an internal 622MHz serial clock from a low-speed crystal
reference clock (77.76MHz, 51.84MHz, or 38.88MHz).
The MAX3690 is available in the extended-industrial
temperature range (-40°C to +85°C) in a 32-pin TQFP
package.
♦ Selectable Reference Clock Frequency:
77.76MHz, 51.84MHz, or 38.88MHz
♦ Single +3.3V Supply
♦ 77Mbps (8-bit) Parallel to 622Mbps Serial
Conversion
♦ Clock Synthesis for 622Mbps Serial Data
♦ 200mW Power
♦ TTL Parallel Clock and Data Inputs
♦ Differential 3.3V PECL Serial-Data Output
________________________Applications
Ordering Information
622Mbps SDH/SONET Transmission Systems
PART
622Mbps ATM/SONET Access Nodes
MAX3690ECJ
TEMP. RANGE
PIN-PACKAGE
-40°C to +85°C
32 TQFP
Add/Drop Multiplexers
Digital Cross Connects
Pin Configuration appears at end of data sheet.
Typical Operating Circuit
38.88MHz TTL CRYSTAL
REFERENCE
PCLKI
OVERHEAD
GENERATION
PD0
PD1
PD2
PD3
PD4
PD5
PD6
PD7
PCLKO
VCC = +3.3V
RCLK
VCC
1µF
1µF
CKSET
MAX3690
FIL+
FIL-
GND
SD-
SD+
VCC = +3.3V
VCC = +3.3V
130Ω
130Ω
MAX3668
82Ω
82Ω
THIS SYMBOL REPRESENTS A TRANSMISSION LINE
OF CHARACTERISTIC IMPEDANCE (Z0 = 50Ω).
________________________________________________________________ Maxim Integrated Products
1
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For small orders, phone 1-800-835-8769.
MAX3690
General Description
MAX3690
+3.3V, 622Mbps, SDH/SONET 8:1 Serializer
with Clock Synthesis and TTL Inputs
ABSOLUTE MAXIMUM RATINGS
Terminal Voltage (with respect to GND)
VCC .......................................................................-0.5V to +5V
All Inputs, FIL-, FIL+, PCLKO .................-0.5V to (VCC + 0.5V)
Output Current
PECL Outputs (SD±).......................................................50mA
Continuous Power Dissipation (TA = +85°C)
TQFP (derate 10.2mW/°C above +85°C) .....................663mW
Operating Temperature Range ...........................-40°C to +85°C
Storage Temperature Range .............................-60°C to +160°C
Lead Temperature (soldering, 10sec) .............................+300°C
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.
DC ELECTRICAL CHARACTERISTICS
(VCC = +3.0V to +3.6V, PECL loads = 50Ω ±1% to (VCC - 2V), TA = -40°C to +85°C, unless otherwise noted. Typical values are at
VCC = +3.3V, TA = +25°C.)
PARAMETER
Supply Current
CKSET Input Current
SYMBOL
ICC
ICKSET
CONDITIONS
MIN
TYP
PECL outputs unterminated
60
CKSET = 0 or VCC
MAX
UNITS
100
mA
500
µA
PECL OUTPUTS (SD±)
Output High Voltage
VOH
Output Low Voltage
VOL
TA = 0°C to +85°C
VCC - 1.025
VCC - 0.88
TA = -40°C
VCC - 1.085
VCC - 0.88
TA = 0°C to +85°C
VCC - 1.81
VCC - 1.62
TA = -40°C
VCC - 1.83
VCC - 1.555
V
V
TTL INPUTS AND OUTPUTS (PCLKI, RCLK, PCLKO, PD_)
Input High Voltage
VIH
Input Low Voltage
VIL
2.0
Input High Current
IIH
VIN = VCC
Input Low Current
IIL
VIN = 0
2.4
Output High Voltage
VOH
IOH = 400µA
Output Low Voltage
VOL
IOL = -400µA
V
0.8
V
-10
10
µA
-10
10
µA
V
0.44
V
AC ELECTRICAL CHARACTERISTICS
(VCC = +3.0V to +3.6V, PECL loads = 50Ω ±1% to (VCC - 2V), all TTL thresholds set to VCC/2, TA = -40°C to +85°C, unless otherwise
noted. Typical values are at VCC = +3.3V, TA = +25°C.) (Note 1)
PARAMETER
Serial Clock Rate
SYMBOL
CONDITIONS
MIN
fSCLK
TYP
MAX
622.08
UNITS
MHz
Parallel Data Setup Time
tSU
1200
ps
Parallel Data Hold Time
tH
1000
ps
tSKEW
0
Allowable Parallel Clock Output
to Parallel Clock Input Delay
Output Random Jitter
PECL Differential Output
Rise/Fall Time
Φ0
tR, tF
5.0
ns
11
psRMS
20% to 80%
200
ps
TTL Output Rise Time
tR
CLOAD = 15pF, VOUT = 0.8V to 2.0V
650
ns
TTL Output Fall Time
tF
CLOAD = 15pF, VOUT = 0.8V to 2.0V
550
ns
Note 1: AC characteristics guaranteed by design and characterization.
Note 2: All TTL thresholds set to VCC / 2.
2
_______________________________________________________________________________________
+3.3V, 622Mbps, SDH/SONET 8:1 Serializer
with Clock Synthesis and TTL Inputs
PARALLEL DATA SETUP TIME
vs. TEMPERATURE
65
60
55
50
-65
-70
-75
-80
-85
-25
0
25
50
75
100
-40 -25
0
255
250
245
240
25
50
75
-40
85
SERIAL DATA RANDOM JITTER
(RCLKI = 77.76MHz)
0
25
50
75
85
SERIAL-DATA OUTPUT EYE DIAGRAM
(622Mbps, PRBS)
ALLOWED PCLKO to PCLKI SKEW
vs. TEMPERATURE
MAX3690-07
15
MAX3690-05
-25
TEMPERATURE (°C)
TEMPERATURE (¡C)
TEMPERATURE (°C)
VCC = 3.3V
260
230
-95
-50
265
235
-90
45
270
MAX3690-03
MAX3690-02
-60
MAX3690-08
SUPPLY CURRENT (mA)
70
-55
PARALLEL DATA SETUP TIME (ps)
MAX3690-01
75
PARALLEL DATA HOLD TIME
vs. TEMPERATURE
PARALLEL DATA HOLD TIME (ps)
SUPPLY CURRENT vs. TEMPERATURE
10
TIME (ns)
2mV/
div
100mV/
div
5
0
RJ = 4.66psRMS
5ps/div
TEMPERATURE (°C)
-5
0
-50
0
50
100
200ps/div
TEMPERATURE (°C)
_______________________________________________________________________________________
3
MAX3690
__________________________________________Typical Operating Characteristics
(VCC = +3.3V, TA = +25°C, unless otherwise noted.)
MAX3690
+3.3V, 622Mbps, SDH/SONET 8:1 Serializer
with Clock Synthesis and TTL Inputs
______________________________________________________________Pin Description
PIN
NAME
FUNCTION
1–8
PD0–PD7
9, 10, 17,
18, 19, 24,
25, 26,
31, 32
GND
11
PCLKO
12, 13, 16,
21, 28, 29
VCC
+3.3V Supply Voltage
14
SD-
Inverting PECL Serial-Data Output
15
SD+
Noninverting PECL Serial-Data Output
TTL Parallel-Data Inputs. Data is clocked in on the PCLKI signal’s positive transition.
Ground
TTL Parallel-Clock Output. Use positive transition of PCLKO to clock the overhead management
circuit.
Reference Clock Rate Programming Pin.
CKSET = open: Reference clock rate = 77.76MHz
CKSET = 20kΩ to GND: Reference clock rate = 51.84MHz
CKSET = GND: Reference clock rate = 38.88MHz
20
CKSET
22
FIL-
Filter Capacitor Input. Connect a 1µF capacitor between FIL- and VCC.
23
FIL+
Filter Capacitor Input. Connect a 1µF capacitor between FIL- and VCC.
27
RCLK
TTL Reference-Clock Input. Connect a crystal reference clock (77.76MHz, 51.84MHz or 38.88MHz) to
the RCLK input. The active edge is the positive transitioning edge.
30
PCLKI
TTL Parallel-Clock Input. Connect the incoming parallel-data-clock signal to the PCLKI input. The
active edge is the positive transitioning edge.
_______________Detailed Description
The MAX3690 serializer comprises an 8-bit parallel
input register, an 8-bit shift register, control and timing
logic, a PECL output buffer, TTL input/output buffers,
and a frequency-synthesizing PLL (consisting of a
phase/frequency detector, loop filter/amplifier, voltagecontrolled oscillator, and programmable prescaler).
This device converts 8-bit-wide, 77Mbps parallel data
to 622Mbps serial data (Figure 1).
The PLL synthesizes an internal 622MHz reference
used to clock the output shift register. This clock is
generated by locking onto the external crystal reference clock signal (RCLK) operating at either
77.76MHz, 51.84MHz, or 38.88MHz. The incoming par-
4
allel data is clocked into the MAX3690 on the rising
transition of the parallel-clock-input signal (PCLKI). The
control and timing logic ensure proper operation if the
parallel-input register is latched within a window of time
that is defined with respect to the parallel-clock-output
signal (PCLKO). PCLKO is the synthesized 622MHz
internal serial-clock signal divided by eight. Parallelclock output to parallel-clock-input delay (skew) must
be observed. Figure 2 shows the timing diagram.
PECL Outputs
The serial-data PECL outputs (SD+, SD-) require 50Ω
DC termination to (VCC - 2V). See the Alternative PECLOutput Termination section.
_______________________________________________________________________________________
+3.3V, 622Mbps, SDH/SONET 8:1 Serializer
with Clock Synthesis and TTL Inputs
PD6
TTL
TTL
PD5
PD4
TTL
TTL
TTL
PD1
PD0
8-BIT
PARALLEL
INPUT
REGISTER
TTL
PD3
PD2
TTL
TTL
PCLKI
TTL
PRESCALER
CKSET
RCLK
MAX3690
PD7
SHIFT
PHASE/FREQ
DETECT
TTL
VCO
CONTROL
LATCH
8-BIT
SHIFT
REGISTER
PECL
SDOH
SDOL
TTL
MAX3690
FIL+ FIL-
PCLKO
Figure 1. Functional Diagram
PCLKO
tSKEW
PCLKI
tSU
PD_
tH
VALID PARALLEL DATA
SD
D7
D6
D5
D4
D3
D2
D1
D0
NOTE: PD7 = D7, PD6 = D6, PD5 = D5, PD4 = D4, PD3 = D3, PD2 = D2, PD1 = D1, PD0 = D0
Figure 2. Timing Diagram
_______________________________________________________________________________________
5
MAX3690
+3.3V, 622Mbps, SDH/SONET 8:1 Serializer
with Clock Synthesis and TTL Inputs
__________Applications Information
+3.3V
Alternative PECL-Output Termination
Figure 3 shows alternative PECL-output-termination
methods. Use Thevenin-equivalent termination when a
(VCC - 2V) termination voltage is not available. If AC
coupling is necessary, be sure that the coupling
capacitor is placed following the 50Ω or Theveninequivalent DC termination.
130Ω
130Ω
MAX3690
Layout Techniques
SD+
Z0 = 50Ω
SD-
Z0 = 50Ω
For best performance, use good high-frequency layout
techniques. Filter voltage supplies and keep ground
connections short. Use multiple vias where possible.
Also, use controlled-impedance transmission lines to
interface with the MAX3690 data outputs.
PECL
INPUTS
82Ω
82Ω
MAX3690
SD+
Z0 = 50Ω
SD-
Z0 = 50Ω
50Ω
HIGHIMPEDENCE
INPUTS
50Ω
VCC - 2V
Figure 3. Alternative PECL-Output Termination
6
_______________________________________________________________________________________
+3.3V, 622Mbps, SDH/SONET 8:1 Serializer
with Clock Synthesis and TTL Inputs
24
23
22
21
20
19
18
17
GND
FIL+
FILVCC
CKSET
GND
GND
GND
TOP VIEW
MAX3690
Pin Configuration
MAX3690
16
15
14
13
12
11
10
9
VCC
SD+
SDVCC
VCC
PCLKO
GND
GND
1
2
3
4
5
6
7
8
25
26
27
28
29
30
31
32
PD0
PD1
PD2
PD3
PD4
PD5
PD6
PD7
GND
GND
RCLK
VCC
VCC
PCLKI
GND
GND
TQFP
_______________________________________________________________________________________
7
+3.3V, 622Mbps, SDH/SONET 8:1 Serializer
with Clock Synthesis and TTL Inputs
TQFPPO.EPS
MAX3690
Package Information
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.
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© 1999 Maxim Integrated Products
Printed USA
is a registered trademark of Maxim Integrated Products.