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Micrel, Inc.
3.3V 10.7Gbps CML LIMITING POST AMPLIFIER W/ TTL SD AND /SD
DESCRIPTION
SY88953L
SY88953L
FEATURES
Single 3.3V power supply Up to 10.7Gbps operation 800mVp-p output swing with 30ps edge rates 28dB voltage gain with 5mVp-p input sensitivity On chip 50 I/O termination Programmable signal detect (SD and /SD) with 6dB hysteresis Chatter-free OC-TTL SD and /SD outputs with internal 5k pull-up resistors can feedback to TTL enable (/EN) input Available in a tiny (3mm x 3mm) 16-pin MLF(R) package or die
APPLICATIONS
OC-192 SDH/SONET 10G Ethernet/Fibre Channel receivers Upto 10.7Gbps proprietary link XFP transceivers Line driver/receiver
The SY88953L high-speed limiting post amplifier is designed for use in fiber-optic receivers. The device connects to typical transimpedance amplifiers (TIAs). The linear signal output from TIAs can contain significant amounts of noise and may vary in amplitude over time. The SY88953L quantizes these signals and outputs CML level waveforms. The SY88953L operates from a single +3.3V power supply, over temperatures ranging from -40C to +85C. With its wide bandwidth and high gain, signals with data rates up to 10.7Gbps and as small as 5mVp-p can be amplified to drive devices with CML inputs. The SY88953L outputs TTL signal-detect (SD and /SD) signals. A programmable signal-detect level set pin (SDLVL) sets the sensitivity of the input amplitude detection. SD asserts high if the input amplitude rises above the threshold set by SDLVL and deasserts low otherwise. /SD is the complementary output of SD. /SD can be fedback to the enable (/EN) input to maintain output stability under a loss of signal condition. /EN deasserts the true output signal without removing the input signal. Typically 6dB SD hysteresis is provided to prevent chattering. The SY88953L also includes an input threshold adjustment to correct pulsewidth distortion.
TYPICAL APPLICATIONS CIRCUIT
SD
VCC
0.1F
VTHP DIN /DIN VTHN
/SD
/EN
DOUT
0.1F
From Transimpedance Amp.
0.1F
SY88953L
SDLVL
/DOUT
To CDR
0.1F
GND
VCC
200k
MicroLeadFrame and MLF are registered trademarks of Amkor Technology, Inc.
M9999-081506 hbwhelp@micrel.com or (408) 955-1690
Rev.: C Amendment: /0
1
Issue Date: August 2006
Micrel, Inc.
SY88953L
PACKAGE/ORDERING INFORMATION
SDLVL
Ordering Information
GND
VTHP
/EN
Part Number
16 15 14 13 12 11 10 9 5 6 7 8
Package Type MLF-16 MLF-16 MLF-16 MLF-16
Operating Range Industrial Industrial Industrial Industrial
Package Marking 953L 953L 953L with Pb-Free bar-line indicator 953L with Pb-Free bar-line indicator
Lead Finish Sn-Pb Sn-Pb Pb-Free NiPdAu Pb-Free NiPdAu
SY88953LMI
DOUT VCC VCC /DOUT
DIN VCC VCC /DIN
1 2 3 4
SY88953LMITR(1) SY88953LMG SY88953LMGTR(1)
Note: 1. Tape and Reel.
VTHN
SD
16-Pin MLF(R)
PIN DESCRIPTION
Pin Number 1 2, 3, 10, 11 4 5 6 Pin Name DIN VCC /DIN VTHN SD Type Data Input Power Supply Data Input Input Open-collector TTL output w/ internal 5k pull-up resistor Open-collector TTL output w/ internal 5k pull-up resistor Ground CML Output CML Output Input TTL Input: Default is high. Input Pin Function True data input w/50 resistor to VCC. Positive power supply. Complementary data input w/50 resistor to VCC. /DIN DC threshold adjustment pin. Signal-Detect: Asserts high when the data input amplitude rises above the threshold set by SDLVL.
7
GND
/SD
/SD
Inverted Signal-Detect: Asserts low when the data input amplitude rises above the threshold set by SDLVL.
8, 13, EP 9 12 14 15 16
GND /DOUT DOUT SDLVL /EN VTHP
Device ground. Exposed pad must be soldered to PCB ground for proper electrical and thermal performance. Complementary data output. True data output. Signal-Detect Level Set: A resistor from this pin to VCC sets the threshold for the data input amplitude at which SD will be asserted. Enable: Deasserts true data output when high. DIN DC threshold adjustement pin.
M9999-081506 hbwhelp@micrel.com or (408) 955-1690
2
Micrel, Inc.
SY88953L
Absolute Maximum Ratings(1)
Supply Voltage (VCC) ................................... -0.5V to +4.0V Data Input Voltage (DIN, /DIN) ... (VCC-1.0V) to (VCC+0.5V) Data Output Voltage (DOUT, /DOUT) .................................... .......................................... (VCC-1.0V) to (VCC+0.5V) Data Output Current (DOUT, /DOUT) ........................... 22mA /EN Voltage ............................................................ 0 to VCC SD, /SD Current ........................................................... 5mA SDLVL Voltage ...................................... (VCC-1.3V) to VCC Storage Temperature (TS) ....................... -65C to +150C
Operating Ratings(2)
Supply Voltage (VCC) .................................. +3.0V to +3.6V Ambient Temperature (TA) ......................... -40C to +85C Junction Temperature (TJ) ....................... -40C to +120C Package Thermal Resistance(3) MLF(R) (JA) Still-Air ..................................................... 59C/W (JB) Still-Air .................................................... 32C/W
DC ELECTRICAL CHARACTERISTICS
VCC = 3.0V to 3.6V; RLOAD = 50 to VCC; TA = -40C to +85C; typical values at VCC = 3.3V, TA = 25C Symbol ICC VSDLVL VIH VIL IIH IIL VOH VOL VOH VOL VOFFSET ZO ZO Parameter Power Supply Current SDLVL Voltage /EN Input HIGH Voltage /EN Input LOW Voltage /EN Input HIGH Current /EN Input LOW Current SD, /SD Output HIGH Level SD, /SD Output LOW Level Output HIGH Voltage Output LOW Voltage Differential Output Offset Single-Ended Output Impedance Single-Ended Input Impedance IOL = +2mA 50 to VCC output load 50 to VCC output load VIN = VCC VIN = 0.5V -0.3 2.4 0.5 VCC-0.020 VCC-0.005 VCC VCC-0.560 VCC-0.400 VCC-0.240 80 40 40 50 50 60 60 Condition no output load VCC-1.3 2.0 0.8 20 Min Typ 110 Max 170 VCC Units mA V V V A mA V V V V mV
Note s: 1. Permanent device damage may occur if absolute maximum ratings are exceeded. This is a stress rating only and functional operation is not implied at conditions other than those detailed in the operational sections of this data sheet. Exposure to absolute maximum ratlng conditions for extended periods may affect device reliability. 2. The data sheet limits are not guaranteed if the device is operated beyond the operating ratings. 3. Exposed pad must be soldrered to PCB's ground plane.
M9999-081506 hbwhelp@micrel.com or (408) 955-1690
3
Micrel, Inc.
SY88953L
AC ELECTRICAL CHARACTERISTICS
VCC = 3.0V to 3.6V; RLOAD = 50 to VCC; TA = -40C to +85C; typical values at VCC = 3.3V, TA = 25C Symbol HYS PSRR tOFF tON tr,tf VID VOD VSR AV(Diff) S21 B-3dB Parameter SD Hysteresis Power Supply Rejection Ratio SD, /SD Release Time SD, /SD Assert Time Output Rise/Fall Time Differential Input Voltage Swing Differential Output Voltage Swing SD Sensitivity Range Differential Voltage Gain Single-Ended Small-Signal Gain 3dB Bandwidth VID 50mVPP 5 480 5 22 16 28 22 7.5 800 Condition electrical signal Min 2 Typ 6 35 0.1 0.2 30 0.5 0.5 35 1800 1120 50 Max 8 Units dB dB s s ps mVPP mVPP mVPP dB dB GHz
M9999-081506 hbwhelp@micrel.com or (408) 955-1690
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Micrel, Inc.
SY88953L
TYPICAL OPERATING CHARACTERISTICS
120 100
SD Assert and Deassert Levels vs. SDLVL
DIN OFFSET (VCC - mV)
3.3V TA = 25C 10Gbps Pattern 223-1 Assert
0 -50 -100 -150 -200 -250 -300 0
DIN OFFSET vs. VTH
INPUT (mVp-p)
80 60 40
Deassert 20 0 -1 -0.8 -0.6 -0.4 -0.2 SDLVL=VCC - V 0.0
1.0
2.0 VTH (V)
3.0
4.0
(5mV/div.)
23ns
TIME (20ps/div.)
23.15ns
Example of Using VTH to Cancel Effect of Pulse Width Distortion
(3.3V, 27C, 10Gbps) 30mVPP Differential Input
M9999-081506 hbwhelp@micrel.com or (408) 955-1690
5
Micrel, Inc.
SY88953L
DETAILED DESCRIPTION
The SY88953L high-speed limiting post amplifier operates from a single +3.3V power supply, over temperatures from -40C to +85C. Signals with data rates up to 10.7Gbps and as small as 5mVp-p can be amplified. Figure 1 shows the allowed input voltage swing. The SY88953L generates SD and /SD outputs. SDLVL sets the sensitivity of the input amplitude detection. The SY88953L also includes an input threshold adjustment to correct pulsewidth distortion Input Amplifier/Buffer Figure 2 shows a simplified schematic of the SY88953L's input stage. The high-sensitivity of the input amplifier allows signals as small as 5mVp-p to be detected and amplified. The input amplifier allows input signals as large as 1800mVpp. Input signals are linearly amplified with a typically 28dB differential voltage gain. Since it is a limiting amplifier, the SY88953L outputs typically 800mV PP voltage-limited waveforms for input signals that are greater than 32mVp-p. Applications requiring the SY88953L to operate with highgain should have the upstream TIA placed as close as possible to the SY88953L's input pins to ensure the best performance of the device. Threshold Adjustment The SY88953L's duty cycle can be controlled by forcing an offset at either input using VTHP or VTHN. Typically, only one of the inputs is required to be adjusted, depending on the required direction of the pulse width adjustment. The SY88953L implements current source based offset control of the inputs. "Typical Operating Characteristics" shows the offset applied to the input for a given VTH voltage. This feature is disabled by simply setting VTH to GND. Output Buffer The SY88953L's CML output buffer is designed to drive 50 lines. The output buffer requires appropriate termination for proper operation. An external 50 resistor to VCC for each output pin provides this. Figure 3 shows a simplified schematic of the output stage and includes an appropriate termination method. Of course, driving a downstream device that is internally terminated with 50 to VCC eliminates the need for external termination. As noted in the previous section, the amplifier outputs typically 800mVp-p waveforms across 25 total loads. The output buffer thus switches typically 16mA tail-current. Signal-Detect The SY88953L generates chatter-free signal-detect (SD and /SD) open-collector TTL outputs with internal 5k pullup resistors as shown in Figure 4. SD is used to determine that the input amplitude is large enough to be considered a valid input. SD asserts high if the input amplitude rises above the threshold set by SDLVL and deasserts low otherwise. /SD is the complementary output of SD. /SD asserts low if the input amplitude rises above the threshold set by SDLVL and deasserts high otherwise. /SD can be fed back to the enable (/EN) input to maintain output stability under a loss of signal condition. /EN deasserts the true output signal without removing the input signals. Typically 6dB SD hysteresis is provided to prevent chattering. Signal-Detect Level Set A programmable signal-detect level set pin (SDLVL) sets the threshold of the input amplitude detection. Connecting an external resistor between VCC and SDLVL sets the voltage at SDLVL. This voltages ranges from VCC to VCC-1.3V. The external resistor creates a voltage divider between VCC and VCC-1.3V as shown in Figure 5. If desired, an appropriate external voltage may be applied rather than using a resistor. The smaller the external resistor, implying a smaller voltage difference from SDLVL to VCC, the smaller the SD sensitivity. Hence, larger input amplitude is required to assert SD. "Typical Operating Characteristics" shows the relationship between the input amplitude detection sensitivity and the SDLVL voltage. Hysteresis The SY88953L provides typically 6dB SD electrical hysteresis. By definition, a power ratio measured in dB is 10log(power ratio). Power is calculated as V2IN/R for an electrical signal. Hence the same ratio can be stated as 20log(voltage ratio). While in linear mode, the electrical voltage input changes linearly with the optical power and hence the ratios change linearly. Therefore, the optical hysteresis in dB is half the electrical hysteresis in dB given in the datasheet. The SY88953L provides typically 3dB SD optical hysteresis. As the SY88953L is an electrical device, this datasheet refers to hysteresis in electrical terms. With 6dB SD hysteresis, a voltage factor of two is required to assert or deassert SD.
M9999-081506 hbwhelp@micrel.com or (408) 955-1690
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Micrel, Inc.
SY88953L
DATA+
2.5mV (Min.) VIS(mVp-p) 900mV (Max.)
DATA-
(DATA+) - (DATA-)
5mVp-p (Min.) VID(mVp-p) 1800mVp-p (Max.)
Figure 1. VIS and VID Definitions
VCC
VCC
VCC RLOAD 50 50
50
50 DIN 0.1F /DIN 0.1F VTHP VTHN
ESD STRUCTURE
50 Q /Q
Z0 = 50
AC-coupling capacitors
50
Z0 = 50 AC-coupling capacitors
GND
GND
ESD STRUCTURE
Figure 2. Input Structure
Figure 3. Output Structure
VCC RSDLVL SDLVL
VCC 5k SD
3k
VCC -1.3V
Figure 4. SD, /SD Output Structure
Figure 5. SDLVL Setting Circuit
M9999-081506 hbwhelp@micrel.com or (408) 955-1690
7
Micrel, Inc.
SY88953L
FUNCTIONAL BLOCK DIAGRAM
VTHP
VCC
GND VCC 501/2 VCC 501/2 DOUT /DOUT
DIN 501/2 /DIN VCC 501/2 TTL Buffer /EN Amplifier Amplifier
Amplifier
Level Detect SD /SD
TTL Buffer
VTHN
SDLVL
DESIGN PROCEDURE
Layout and PCB Design Since the SY88953L is a high-frequency component, performance can be largely determined by the board layout and design. A common problem with high-gain amplifiers is the feedback from the large swing outputs to the input via the power supply. The SY88953L's ground pins should be connected to the circuit board ground. Use multiple PCB vias close to the part to connect to ground. Avoid long, inductive runs which can degrade performance.
M9999-081506 hbwhelp@micrel.com or (408) 955-1690
8
Micrel, Inc.
SY88953L
16-PIN MicroLeadFrame(R) (MLF-16)
Package EP- Exposed Pad
Die
CompSide Island
Heat Dissipation Heat Dissipation VEE Heavy Copper Plane VEE Heavy Copper Plane
PCB Thermal Consideration for 16-Pin MLF(R) Package (Always solder, or equivalent, the exposed pad to the PCB) Package Notes: 1. Package meets Level 2 qualification. 2. All parts are 100% baked and dry-packaged before shipment. 3. Exposed pads must be soldered to a ground for proper thermal management.
MICREL, INC. 2180 FORTUNE DRIVE SAN JOSE, CA 95131 USA
TEL
+ 1 (408) 944-0800
FAX
+ 1 (408) 474-1000
WEB
http://www.micrel.com
The information furnished by Micrel in this datasheet is believed to be accurate and reliable. However, no responsibility is assumed by Micrel for its use. Micrel reserves the right to change circuitry and specifications at any time without notification to the customer. Micrel Products are not designed or authorized for use as components in life support appliances, devices or systems where malfunction of a product can reasonably be expected to result in personal injury. Life support devices or systems are devices or systems that (a) are intended for surgical implant into the body or (b) support or sustain life, and whose failure to perform can be reasonably expected to result in a significant injury to the user. A Purchaser's use or sale of Micrel Products for use in life support appliances, devices or systems is at Purchaser's own risk and Purchaser agrees to fully indemnify Micrel for any damages resulting from such use or sale. (c) 2005 Micrel, Incorporated. M9999-081506 hbwhelp@micrel.com or (408) 955-1690
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