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FEATURES

LT6559 Low Cost 5V/5V 300MHz Triple Video Amplifier in 3mm x 3mm QFN DESCRIPTION
The LT(R)6559 is a low cost, high speed, triple amplifier that has been optimized for excellent video performance on a single 5V supply, yet fits in the small footprint of a 3mm x 3mm QFN package. With a -3dB bandwidth of 300MHz, a 0.1dB bandwidth of 150MHz, and a slew rate of 800V/s, the LT6559's dynamic performance is an excellent match for high speed RGB or YPBPR video applications. For multiplexing applications such as KVM switches or selectable video inputs, each channel has an independent high speed enable/disable pin. Each amplifier will turn on in 30ns and off in 40ns. When enabled, each amplifier draws 3.9mA from a 5V supply. The LT6559 operates on a single supply voltage ranging from 4V to 12V, and on split supplies ranging from 2V to 6V. The LT6559 comes in a compact 16-lead 3mm x 3mm QFN package, and operates over a -40C to 85C temperature range. The LT6559 is manufactured on Linear Technology's proprietary complementary bipolar process.
, LT, LTC and LTM are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners.

300MHz Bandwidth on Single 5V and 5V (AV = 1, 2 and -1) 0.1dB Gain Flatness: 150MHz (AV = 1, 2 and -1) High Slew Rate: 800V/s Wide Supply Range: 2V to 6V (Dual Supply) 4V to 12V (Single Supply) 80mA Output Current Low Supply Current: 3.9mA/Amplifier Shutdown Mode Fast Turn-On Time: 30ns Fast Turn-Off Time: 40ns Small 0.75mm Tall 16-Lead 3mm x 3mm QFN Package
APPLICATIONS

RGB/YPBPR Cable Drivers LCD Projectors KVM Switches A/V Receivers MUX Amplifiers Composite Video Cable Drivers ADC Drivers
TYPICAL APPLICATION
3-Input Video MUX Cable Driver
5V A VIN A RG 182
+ -
- 5V VIN B
EN A
CHANNEL SELECT B
Square Wave Response
C 100
1/3 LT6559 RF 301
5V
+
RG 182
EN B 100
75 CABLE VOUT 75
OUTPUT 200mV/DIV
1/3 LT6559
-
- 5V VIN C RG 182 RF 301 5V
+ -
- 5V
EN C 100
TIME (10ns/DIV) RL = 100 RF = RG = 301 f = 10MHz
6559 TA02
1/3 LT6559
6559 TA01
RF 301
6559f
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LT6559 ABSOLUTE MAXIMUM RATINGS
(Note 1)
PACKAGE/ORDER INFORMATION
TOP VIEW OUT R 12 V + 17 11 EN G 10 OUT G 9 5 +IN B 6 -IN B 7 EN B 8 OUT B V- +IN R -IN R EN R 16 15 14 13 *GND 1 -IN G 2 +IN G 3 *GND 4
Total Supply Voltage (V+ to V-) ..............................12.6V Input Current (Note 2)......................................... 10mA Output Current .................................................. 100mA Differential Input Voltage (Note 2) ............................5V Output Short-Circuit Duration (Note 3) ........ Continuous Operating Temperature Range (Note 9) -40C to 85C Specified Temperature Range (Note 4) .. -40C to 85C Storage Temperature Range.................. -65C to 125C Junction Temperature (Note 5) ............................ 125C
UD PACKAGE 16-LEAD (3mm x 3mm) PLASTIC QFN
TJMAX = 125C, JA = 68C/W, JC = 4.2C/W EXPOSED PAD (PIN 17) IS V -, MUST BE SOLDERED TO THE PCB
ORDER PART NUMBER LT6559CUD
UD PART MARKING LCHG
Order Options Tape and Reel: Add #TR Lead Free: Add #PBF Lead Free Tape and Reel: Add #TRPBF Lead Free Part Marking: http://www.linear.com/leadfree/ Consult LTC Marketing for parts specified with wider operating temperature ranges. * Ground pins are not internally connected. For best channel isolation, connect to ground.
5V ELECTRICAL CHARACTERISTICS
SYMBOL VOS VOS /T IIN+ IIN - en +in -in RIN CIN COUT VINH VINL VOUTH VOUTL VOUTH PARAMETER Input Offset Voltage
The denotes specifications which apply over the specified operating temperature range, otherwise specifications are at TA = 25C. For each amplifier: VCM = 2.5V, VS = 5V, EN = 0V, pulse tested, unless otherwise noted. (Note 4)
CONDITIONS
MIN
TYP 1.5
MAX 10 12 25 30 60 70
UNITS mV mV V/C A A A A nV/Hz pA/Hz pA/Hz M pF pF pF V
Input Offset Voltage Drift Noninverting Input Current

15 10 10
Inverting Input Current
Input Noise Voltage Density Noninverting Input Noise Current Density Inverting Input Noise Current Density Input Resistance Input Capacitance Output Capacitance Input Voltage Range, High Input Voltage Range, Low Maximum Output Voltage Swing, High Maximum Output Voltage Swing, Low Maximum Output Voltage Swing, High
f = 1kHz, RF = 1k, RG = 10, RS = 0 f = 1kHz f = 1kHz VIN = 1V Amplifier Enabled Amplifier Disabled Amplifier Disabled 3.5 RL = 100k RL = 100k RL = 150 RL = 150
4.5 6 25 0.14 2.0 2.5 8.5 4.0 1.0 4.1 3.85 3.65 4.15 0.85 3.95 0.9 1.5
V V V V V
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LT6559 5V ELECTRICAL CHARACTERISTICS
SYMBOL VOUTL CMRR PSRR ROL IOUT IS IEN SR tON tOFF tr, tf tPD os tS dG dP PARAMETER Maximum Output Voltage Swing, Low Common Mode Rejection Ratio Power Supply Rejection Ratio Transimpedance, VOUT/IIN- Maximum Output Current Supply Current per Amplifier Disable Supply Current per Amplifier Enable Pin Current Slew Rate (Note 6) Turn-On Delay Time (Note 7) Turn-Off Delay Time (Note 7) Small-Signal Rise and Fall Time Propagation Delay Small-Signal Overshoot Settling Time Differential Gain (Note 8) Differential Phase (Note 8) AV = 10, RL = 150, VS = 5V RF = RG = 301, RL = 150, VS = 5V RF = RG = 301, RL = 150, VS = 5V RF = RG = 301, RL = 150, VOUT = 1VP-P, VS = 5V RF = RG = 301, RL = 150, VOUT = 1VP-P, VS = 5V RF = RG = 301, RL = 150, VOUT = 1VP-P, VS = 5V 0.1%, AV = -1V, RF = RG = 301, RL = 150, VS = 5V RF = RG = 301, RL = 150, VS = 5V RF = RG = 301, RL = 150, VS = 5V EN Pin Voltage = 4.5V, RL = 150
The denotes specifications which apply over the specified operating temperature range, otherwise specifications are at TA = 25C. For each amplifier: VCM = 2.5V, VS = 5V, EN = 0V, pulse tested, unless otherwise noted. (Note 4)
CONDITIONS RL = 150 RL = 150 VCM = 1.5V to 3.5V VS = 2V to 5V, EN = V - VOUT = 1.5V to 3.5V, RL = 150 RL = 0

MIN
TYP 1.05
MAX 1.15 1.35
UNITS V V dB dB k mA
40 56 40
50 70 80 65 3.9 0.1 30 500 30 40 1.3 2.5 10 25 0.13 0.10 75 100 6.1 100
mA A A V/s ns ns ns ns % ns % DEG
5V ELECTRICAL CHARACTERISTICS
SYMBOL VOS VOS/T IIN en +in -in RIN CIN COUT VINH VINL VOUTH
+
The denotes specifications which apply over the specified operating temperature range, otherwise specifications are at TA = 25C. For each amplifier: VCM = 0V, VS = 5V, EN = 0V, pulse tested, unless otherwise noted. (Note 4)
PARAMETER Input Offset Voltage Input Offset Voltage Drift Noninverting Input Current Inverting Input Current Input Noise Voltage Density Noninverting Input Noise Current Density Inverting Input Noise Current Density Input Resistance Input Capacitance Output Capacitance Input Voltage Range, High Input Voltage Range, Low Maximum Output Voltage Swing, High RL = 100k 4.0 f = 1kHz, RF = 1k, RG = 10, RS = 0 f = 1kHz f = 1kHz VIN = 3.5V Amplifier Enabled Amplifier Disabled Amplifier Disabled VS = 5V 3.5
CONDITIONS
MIN
TYP 1.5 15 10 10 4.5 6 25 1 2.0 2.5 8.5 4.0 -4.0 4.2
MAX 10 25 60
UNITS mV V/C A A nV/Hz pA/Hz pA/Hz M pF pF pF V
IIN-
-3.5
V V
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LT6559 5V ELECTRICAL CHARACTERISTICS
SYMBOL VOUTL VOUTH VOUTL CMRR PSRR ROL IOUT IS IEN SR tON tOFF tr, tf tPD os tS dG dP PARAMETER Maximum Output Voltage Swing, Low Maximum Output Voltage Swing, High Maximum Output Voltage Swing, Low Common Mode Rejection Ratio Power Supply Rejection Ratio Transimpedance, VOUT/IIN- Maximum Output Current Supply Current per Amplifier Disable Supply Current per Amplifier Enable Pin Current Slew Rate (Note 6) Turn-On Delay Time (Note 7) Turn-Off Delay Time (Note 7) Small-Signal Rise and Fall Time Propagation Delay Small-Signal Overshoot Settling Time Differential Gain (Note 8) Differential Phase (Note 8) AV = 10, RL = 150 RF = RG = 301, RL = 150 RF = RG = 301, RL = 150 RF = RG = 301, RL = 150, VOUT = 1VP-P RF = RG = 301, RL = 150, VOUT = 1VP-P RF = RG = 301, RL = 150, VOUT = 1VP-P 0.1%, AV = -1, RF = RG = 301, RL = 150 RF = RG = 301, RL = 150 RF = RG = 301, RL = 150 500 RL = 100k RL = 150 RL = 150 RL = 150 RL = 150 VCM = 3.5V VS = 2V to 5V, EN = V - VOUT = 2V, RL = 150 RL = 0 VOUT = 0V EN Pin Voltage = 4.5V, RL = 150

The denotes specifications which apply over the specified operating temperature range, otherwise specifications are at TA = 25C. For each amplifier: VCM = 0V, VS = 5V, EN = 0V, pulse tested, unless otherwise noted. (Note 4)
CONDITIONS MIN 3.4 3.2 TYP -4.2 3.6 -3.6 42 56 40 52 70 100 100 4.6 0.1 30 800 30 40 1.3 2.5 10 25 0.13 0.10 75 100 6.5 100 -3.4 -3.2 MAX -4.0 UNITS V V V V V dB dB k mA mA A A V/s ns ns ns ns % ns % DEG
Note 1: Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. Exposure to any Absolute Maximum Rating condition for extended periods may affect device reliability and lifetime. Note 2: This parameter is guaranteed to meet specified performance through design and characterization. It has not been tested. Note 3: A heat sink may be required depending on the power supply voltage and how many amplifiers have their outputs short circuited. Note 4: The LT6559 is guaranteed to meet specified performance from 0C to 70C and is designed, characterized and expected to meet these extended temperature limits, but is not tested or QA sampled at -40C and 85C. Note 5: TJ is calculated from the ambient temperature TA and the power dissipation PD according to the following formula: TJ = TA + (PD * 68C/W) Note 6: At 5V, slew rate is measured at 2V on a 3V output signal. At 5V, slew rate is measured from 2V to 3V on a 1.5V to 3.5V output signal. Slew
rate is 100% production tested at 5V for both the rising and falling edge of the B channel. The slew rate of the R and G channels is guaranteed through design and characterization. Note 7: Turn-on delay time (tON) is measured from control input to appearance of 1V at the output, for VIN = 1V. Likewise, turn-off delay time (tOFF) is measured from control input to appearance of 0.5V on the output for VIN = 0.5V. This specification is guaranteed by design and characterization. Note 8: Differential gain and phase are measured using a Tektronix TSG120YC/NTSC signal generator and a Tektronix 1780R Video Measurement Set. The resolution of this equipment is 0.1% and 0.1. Ten identical amplifier stages were cascaded giving an effective resolution of 0.01% and 0.01. Note 9: The LT6559 is guaranteed functional over the operating temperature range of -40C to 85C.
TYPICAL AC PERFORMANCE
VS (V) 5, 5 5, 5 5, 5 AV 1 2 -1 RL () 150 150 150 RF () 365 301 301 RG () 301 301 SMALL SIGNAL -3dB BW (MHz) 300 300 300 SMALL SIGNAL 0.1dB BW (MHz) 150 150 150 SMALL SIGNAL PEAKING (dB) 0.05 0 0
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LT6559 TYPICAL PERFORMANCE CHARACTERISTICS
Closed-Loop Gain vs Frequency (AV = 1)
4 2 GAIN (dB) 0 -2 -4 1M 10M 100M FREQUENCY (Hz) VS = 5V VIN = -10dBm RF = 365 RL = 150 1G
6559 G01
Closed-Loop Gain vs Frequency (AV = 2)
10 8 GAIN (dB) 6 4 2 1M 10M 100M FREQUENCY (Hz) VS = 5V VIN = -10dBm RF = RG = 301 RL = 150 1G
6559 G02
Closed-Loop Gain vs Frequency (AV = -1)
4 2 GAIN (dB) 0 -2 -4 1M 10M 100M FREQUENCY (Hz) VS = 5V VIN = -10dBm RF = RG = 301 RL = 150 1G
6559 G03
Large-Signal Transient Response (AV = 1)
Large-Signal Transient Response (AV = 2)
Large-Signal Transient Response (AV = -1)
OUTPUT (1V/DIV)
OUTPUT (1V/DIV)
VS = 5V VIN = 2.5V RF = 365 RL = 150
TIME (5ns/DIV)
6559 G04
TIME (5ns/DIV) VS = 5V VIN = 1.25V RF = RG = 301 RL = 150
6559 G05
OUTPUT (1V/DIV)
TIME (5ns/DIV) VS = 5V VIN = 2.5V RF = RG = 301 RL = 150
6559 G06
2nd and 3rd Harmonic Distortion vs Frequency
30 TA = 25C 40 RF = RG = 301 RL = 150 50 VS = 5V VOUT = 2VPP 60 HD2 70 80 90 100 110 1 10 100 1000 10000 100000 FREQUENCY (kHz)
6559 G07
Maximum Undistorted Output Voltage vs Frequency
8 7 OUTPUT VOLTAGE (VP-P) AV = +1 6 5 4 3 2 1 TA = 25C RF = 301 RL = 150 VS = 5V 10 FREQUENCY (MHz) 100
6559 G08
PSRR vs Frequency
80 70
AV = +2 PSRR (dB)
60 50 40 30 20 10 TA = 25C RF = RG = 301 RL = 150 AV = +2 100k 1M 10M FREQUENCY (Hz) 100M
6559 G09
DISTORTION (dB)
- PSRR
+ PSRR
HD3
0 10k
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LT6559 TYPICAL PERFORMANCE CHARACTERISTICS
Input Voltage Noise and Current Noise vs Frequency
1000 INPUT NOISE (nV/Hz OR pA/Hz) 100 RF = RG = 301 AV = +2 VS = 5V 100 OUTPUT IMPEDANCE () 10
Output Impedance vs Frequency
100k OUTPUT IMPEDANCE (DISABLED) ()
Output Impedance (Disabled) vs Frequency
RF = 365 AV = +1 VS = 5V 10k
- IN 10 EN +IN
1
1k
0.1
1 10 30 100 300 1k 3k 10k 30k 100k FREQUENCY (Hz)
6559 G10
0.01 10k
100k
1M 10M FREQUENCY (Hz)
100M
6559 G11
100 100k
1M 10M FREQUENCY (Hz)
100M
6559 G12
Maximum Capacitive Load vs Feedback Resistor
1000 OUTPUT SERIES RESISTANCE () 40
Capacitive Load vs Output Series Resistor
RF = RG = 301 VS = 5V OVERSHOOT < 2% SUPPLY CURRENT (mA) 30 6 5 4
Supply Current per Amplifier vs Supply Voltage
EN = V -
CAPACITIVE LOAD (pF)
100
EN = 0V 3 2 1
20
10 RF = R G AV = +2 VS = 5V PEAKING 5dB 900 1500 2100 2700 FEEDBACK RESISTANCE () 3300
6559 G13
10
1 300
0 10 100 CAPACITIVE LOAD (pF) 1000
6559 G14
0 0 1 2 7 3 5 6 4 SUPPLY VOLTAGE ( V) 8 9
6559 G15
Output Voltage Swing vs Temperature
5 4 OUTPUT VOLTAGE SWING (V) ENABLE PIN CURRENT (A) 3 2 1 0 -1 -2 -3 -4 -5 50 25 0 75 100 -50 -25 AMBIENT TEMPERATURE (C) 125 RL = 100k RL = 150 RL = 100k RL = 150 - 20 - 10
Enable Pin Current vs Temperature
POSITIVE SUPPLY CURRENT PER AMPLIFIER (mA) VS = 5V EN = 0V - 30 - 40 EN = -5V - 50 - 60 - 70 - 80 - 50 - 25 5.00 4.75 4.50 4.25 4.00 3.75 3.50 3.25
Positive Supply Current per Amplifier vs Temperature
VS = 5V EN = - 5V
EN = 0
50 100 25 75 0 AMBIENT TEMPERATURE (C)
125
3.00 -50 -25
0 50 75 100 25 AMBIENT TEMPERATURE (C)
125
6559 G16
6559 G17
6559 G18
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LT6559 TYPICAL PERFORMANCE CHARACTERISTICS
Input Offset Voltage vs Temperature
3.0 2.5 INPUT OFFSET VOLTAGE (mV) 2.0 1.5 1.0 0.5 0 - 0.5 -1.0 - 50 - 25 50 75 100 25 AMBIENT TEMPERATURE (C) 0 125 INPUT BIAS CURRENT (A) VS = 5V 15 12 IB+ 9 6 3 0 -3 -6 -50 -25
Input Bias Currents vs Temperature
VS = 5V IB-
50 100 25 75 0 AMBIENT TEMPERATURE (C)
125
6559 G19
6559 G20
All Hostile Crosstalk
0 -10 ALL HOSTILE CROSSTALK (dB) -20 -30 -40 -50 -60 -70 -80 -90 -100 100k 1M 10M FREQUENCY (Hz) 100M 500M
6559 G21
All Hostile Crosstalk (Disabled)
-10 -20 ALL HOSTILE CROSSTALK (dB) -30 -40 -50 -60 -70 -80 -90 -100 -110 100k 1M 10M FREQUENCY (Hz) 100M 500M
6559 G24
RF = RG = 301 RL = 150 AV = +2 R G B
RF = RG = 301 RL = 150 AV = +2 R G B
Propagation Delay
Rise Time and Overshoot
|| os = 10%
INPUT 100mV/DIV OUTPUT 200mV/DIV
VOUT 200mV/DIV
|
tPD = 2.5ns
|
6559 G22
TIME (500ps/DIV) AV = +2 RL = 150 RF = RG = 301
| t r = 1.3ns | TIME (500ps/DIV) AV = +2 RL = 150 RF = RG = 301
6559 G23
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LT6559 PIN FUNCTIONS
GND (Pins 1, 4): Ground. Not connected internally. -IN G (Pin 2): Inverting Input of G Channel Amplifier. +IN G (Pin 3): Noninverting Input of G Channel Amplifier. +IN B (Pin 5): Noninverting Input of B Channel Amplifier. -IN B (Pin 6): Inverting Input of B Channel Amplifier. EN B (Pin 7): B Channel Enable Pin. Logic low to enable. OUT B (Pin 8): B Channel Output. V - (Pin 9): Negative Supply Voltage, Usually Ground or -5V. OUT G (Pin 10): G Channel Output. EN G (Pin 11): G Channel Enable Pin. Logic low to enable. V+ (Pin 12): Positive Supply Voltage, Usually 5V. OUT R (Pin 13): R Channel Output. EN R (Pin 14): R Channel Enable Pin. Logic low to enable. -IN R (Pin 15): Inverting Input of R Channel Amplifier. +IN R (Pin 16): Noninverting Input of R Channel Amplifier. Exposed Pad (Pin 17): V -. Must Be Soldered to the PCB.
APPLICATIONS INFORMATION
Feedback Resistor Selection The small-signal bandwidth of the LT6559 is set by the external feedback resistors and the internal junction capacitors. As a result, the bandwidth is a function of the supply voltage, the value of the feedback resistor, the closed-loop gain and the load resistor. Optimized for 5V and single-supply 5V operation, the LT6559 has a -3dB bandwidth of 300MHz at gains of +1, -1, or +2. Refer to the resistor selection guide in the Typical AC Performance table. Capacitance on the Inverting Input Current feedback amplifiers require resistive feedback from the output to the inverting input for stable operation. Take care to minimize the stray capacitance between the output and the inverting input. Capacitance on the inverting input to ground will cause peaking in the frequency response and overshoot in the transient response. Capacitive Loads The LT6559 can drive many capacitive loads directly when the proper value of feedback resistor is used. The required value for the feedback resistor will increase as load capacitance increases and as closed-loop gain decreases. Alternatively, a small resistor (5 to 35) can be put in series with the output to isolate the capacitive load from the amplifier output. This has the advantage that the amplifier bandwidth is only reduced when the capacitive load is present. The disadvantage is that the gain is a function of the load resistance. Power Supplies The LT6559 will operate from single or split supplies from 2V (4V total) to 6V (12V total). It is not necessary to use equal value split supplies, however the offset voltage and inverting input bias current will change. The offset voltage changes about 600V per volt of supply mismatch. The inverting bias current will typically change about 2A per volt of supply mismatch. Slew Rate Unlike a traditional voltage feedback op amp, the slew rate of a current feedback amplifier is dependent on the amplifier gain configuration. In a current feedback amplifier, both the input stage and the output stage have slew rate limitations. In the inverting mode, and for gains of 2 or more in the noninverting mode, the signal amplitude between the input pins is small and the overall slew rate is that of the output stage. For gains less than 2 in the noninverting mode, the overall slew rate is limited by the input stage. The input slew rate of the LT6559 is approximately 600V/s and is set by internal currents and capacitances. The output slew rate is set by the value of the feedback resistor and
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LT6559 APPLICATIONS INFORMATION
internal capacitance. At a gain of 2 with 301 feedback and gain resistors and 5V supplies, the output slew rate is typically 800V/s. Larger feedback resistors will reduce the slew rate as will lower supply voltages. Enable/Disable Each amplifier of the LT6559 has a unique high impedance, zero supply current mode which is controlled by its own EN pin. These amplifiers are designed to operate with CMOS logic; the amplifiers draw 0.1A of current when these pins are high or floated. To activate each amplifier, its EN pin is normally pulled to a logic low. However, supply current will vary as the voltage between the V+ supply and EN is varied. As seen in Figure 1, +IS does vary with (V+ - VEN), particularly when the voltage difference is less than 3V. For normal operation, it is important to keep the EN pin at least 3V below the V+ supply. If a V+ of less than 3V is used, for the amplifier to remain enabled at all times the EN pin should be tied to the V - supply. The enable pin current is approximately 30A when activated. If using CMOS open-drain logic, an external 1k pull-up resistor is recommended to ensure that the LT6559 remains disabled regardless of any CMOS drain-leakage currents.
5.0 4.5 4.0 3.5 +IS (mA) 3.0 2.5 2.0 1.5 1.0 0.5 0 0 1 2 4 3 V + - VEN (V) 5 6 7
6559 F01
The enable/disable times are very fast when driven from standard 5V CMOS logic. Each amplifier enables in about 30ns (50% point to 50% point) while operating on 5V supplies (Figure 2). Likewise, the disable time is approximately 40ns (50% point to 50% point) (Figure 3).
2V OUTPUT 0V
5V EN 0V VS = 5V VIN = 1V RF = 301 RG = 301 RL = 100
6559 F02
Figure 2. Amplifier Enable Time, AV = 2
2V OUTPUT 0V
TA = 25C V + = 5V V - = 0V
V - = - 5V VS = 5V VIN = 1V RF = 301 RG = 301 RL = 100
6559 F03
5V EN 0V
Figure 3. Amplifier Disable Time, AV = 2
Differential Input Signal Swing To avoid any breakdown condition on the input transistors, the differential input swing must be limited to 5V. In normal operation, the differential voltage between the input pins is small, so the 5V limit is not an issue. In the disabled mode however, the differential swing can be the same as the input swing, and there is a risk of device breakdown if the input voltage range has not been properly considered.
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Figure 1. +IS vs (V+ - VEN)
9
LT6559 TYPICAL APPLICATIONS
3-Input Video MUX Cable Driver The application on the first page of this data sheet shows a low cost, 3-input video MUX cable driver. The scope photo below (Figure 4) displays the cable output of a 30MHz square wave driving 150. In this circuit the active amplifier is loaded by the sum of RF and RG of each disabled amplifier. Resistor values have been chosen to keep the total back termination at 75 while maintaining a gain of 1 at the 75 load. The switching time between any two channels is approximately 32ns when both enable pins are driven (Figure 5). When building the board, care was taken to minimize trace lengths at the inverting inputs. The ground plane was also pulled a few millimeters away from RF and RG on both sides of the board to minimize stray capacitance. Using the LT6559 to Drive LCD Displays Driving a variety of XGA and UXGA LCD displays can be a difficult problem because they are usually a capacitive load of over 300pF, and require fast settling. The LT6559 is particularly well suited for driving these LCD displays because it can drive large capacitive loads with a small series resistor at the output, minimizing settling time. As seen in Figure 6, at a gain of +3 with a 16.9 output series resistor and a 330pF load, the LT6559 is capable of settling to 0.1% in 30ns for a 6V step.
EN A
EN B OUTPUT 200mV/DIV OUTPUT
RL = 150 RF = RG = 301 f = 10MHz
5ns/DIV
6559 F04
VS = 5 VINA = VINB = 2VP-P at 3.58MHz
20ns/DIV
6559 F05
Figure 4. Square Wave Response
Figure 5. 3-Input Video MUX Switching Response (AV = 2)
VIN
VOUT
VS = 5 RF = 301
20ns/DIV CL = 330pF RG = 150 RS = 16.9
6559 F06
Figure 6. Large-Signal Pulse Response
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LT6559 TYPICAL APPLICATIONS
Buffered RGB to YPBPR Conversion An LT6559 and an LT1395 can be used to map RGB signals into YPBPR "component" video as shown in Figure 7. The LT1395 performs a weighted inverting addition of all three inputs. The LT1395 output includes an amplification of the R input by: - 324 = - 0 . 30 1 . 07k The amplification of the G input is by: - 324 = - 0 . 59 549 Finally, the B input is amplified by: - 324 = - 0 . 11 2 . 94k Therefore, the LT1395 output is: -0.3R - 0.59G - 0.11B = -Y. This output is further scaled and inverted by -301/150 = -2 by LT6559 section A2, thus producing 2Y. With the division by two that occurs due to the termination resistors, the desired Y signal is generated at the load. The LT6559 section A1 provides a gain of 2 for the R signal, and performs a subtraction of 2Y from the section A2 output. The output resistor divider provides a scaling factor of 0.71 and forms the 75 back-termination resistance. Thus, the signal seen at the terminated load is the desired 0.71(R - Y) = PR. The LT6559 section A3 provides a gain of 2 for the B signal, and also performs a subtraction of 2Y from the section A2 output. The output resistor divider provides a scaling factor of 0.57 and forms the 75 back-termination resistance. Thus the signal seen at the terminated load is the desired 0.57(B - Y) = PB. For this circuit to develop a normal sync on the Y signal, a normal sync must be inserted on each of the R, G, and B inputs. Alternatively, additional circuitry could be added to inject sync directly at the Y output with controlled current pulses.
75 SOURCES R R11 80.6
+
1.07k A1 1/3 LT6559
105 PR 301 261
-
549
G R12 86.6 B R13 76.8 324 2.94k
A2 1/3 LT6559
ALL RESISTORS 1% VS = 3V TO 5V
A3 1/3 LT6559
Figure 7. RGB to YPBPR Conversion
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+
-
Y = 0.30R + 0.59G + 0.11B PB = 0.57 (B - Y) PR = 0.71 (R - Y)
+
-
+
-
LT1395
150
301
301
75 Y 301
301 133 PB 174
6559 F07
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LT6559 TYPICAL APPLICATIONS
YPBPR to RGB Conversion Two LT6559s can be used to map the YPBPR "component" video into the RGB color space as shown in Figure 8. The Y input is properly terminated with 75 and buffered with a gain of 2 by amplifier A2. The PR input is terminated and buffered with a gain of 2.8 by amplifier A1. The PB input is terminated and buffered with a gain of 3.6 by amplifier A3. Amplifier B1 performs an equally weighted addition of amplifiers A1 and A2 outputs, thereby producing 2(Y + 1.4PR), which generates the desired R signal at the terminated load due to the voltage division by 2 caused by the termination resistors. Amplifier B3 forms the equally weighted addition of amplifiers A2 and A3 outputs, thereby producing 2(Y + 1.8PB), which generates the desired B signal at the terminated load. Amplifier B2 performs a weighted summation of all three inputs. The PB signal is amplified overall by: - 301 * 3 . 6 = 2(- 0 . 34) 1 . 54k The PR signal is amplified overall by: - 301 * 2 . 8 = 2(- 0 . 71) 590 The Y signal is amplified overall by: 1k 301 * 1+ * 2 = 2(1) 1k + 698 590 || 1 . 54k Therefore the amplifier B2 output is: 2(Y - 0.34PB - 0.71PR) which generates the desired G signal at the terminated load. The sync present on the Y input is reconstructed on all three R, G, and B outputs.
301 301
-
165 301 1k B1 1/3 LT6559
75 R
+
R = Y + 1.40PR G = Y - 0.34PB - 0.71 PR B = Y + 1.77PB ALL RESISTORS 1% VS = 3V TO 5V
-
A1 1/3 LT6559 PR 75
1k
+
590 301 301 1.54k 301
-
A2 1/3 LT6559 Y 75 118 301 698
-
B2 1/3 LT6559
75 G
+
1k 301
+
301
- -
A3 1/3 LT6559 PB 75 1k B3 1/3 LT6559
75 B
+
+
1k
6559 F08
Figure 8. YPBPR to RGB Conversion
6559f
12
LT6559 TYPICAL APPLICATIONS
Application (Demo) Boards The DC1063A demo board has been created for evaluating the LT6559 and is available directly from Linear Technology. It has been designed as an RGB video buffer/cable driver, using standard VGA 15-pin D-Sub (HD-15) connectors for input and output signals. All sync signals are also passed directly from the input to the output, so the LT6559's performance can be determined by applying a 5V supply to the DC1063A demo board and then inserting the board between a computer's analog video output and a monitor. Schematics for the DC1063A demo board can be found on the back page of this datasheet. As seen in the DC1063A schematic, each amplifier is configured in a gain of 2, with a 75 back-termination resulting in a final gain of 1. Each input is properly terminated for 75 input impedance with AC coupling capacitors at each input and output. Additionally, for proper operation, the positive input of each amplifier is biased to mid-supply with a high impedance resistor divider. As seen below, the DC1063A is a 2-sided board.
6559 F09
Figure 9. DC1063A Component Locator
6559 F10
6559 F11
Figure 10. DC1063A Top Side
Figure 11. DC1063A Bottom Side
6559f
13
LT6559 SIMPLIFIED SCHEMATIC, each amplifier
V+
+IN
-IN
OUT
EN
V-
6559 SS
6559f
14
LT6559 PACKAGE DESCRIPTION
UD Package 16-Lead Plastic QFN (3mm x 3mm)
(Reference LTC DWG # 05-08-1691)
0.70 0.05
3.50 0.05 1.45 0.05 2.10 0.05 (4 SIDES)
PACKAGE OUTLINE 0.25 0.05 0.50 BSC RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS 0.75 0.05 BOTTOM VIEW--EXPOSED PAD R = 0.115 TYP 15 16 0.40 0.10 1 1.45 0.10 (4-SIDES) 2 PIN 1 NOTCH R = 0.20 TYP OR 0.25 x 45 CHAMFER
3.00 0.10 (4 SIDES) PIN 1 TOP MARK (NOTE 6)
(UD16) QFN 0904
0.200 REF 0.00 - 0.05 NOTE: 1. DRAWING CONFORMS TO JEDEC PACKAGE OUTLINE MO-220 VARIATION (WEED-2) 2. DRAWING NOT TO SCALE 3. ALL DIMENSIONS ARE IN MILLIMETERS 4. DIMENSIONS OF EXPOSED PAD ON BOTTOM OF PACKAGE DO NOT INCLUDE MOLD FLASH. MOLD FLASH, IF PRESENT, SHALL NOT EXCEED 0.15mm ON ANY SIDE 5. EXPOSED PAD SHALL BE SOLDER PLATED 6. SHADED AREA IS ONLY A REFERENCE FOR PIN 1 LOCATION ON THE TOP AND BOTTOM OF PACKAGE
0.25 0.05 0.50 BSC
6559f
Information furnished by Linear Technology Corporation is believed to be accurate and reliable. However, no responsibility is assumed for its use. Linear Technology Corporation makes no representation that the interconnection of its circuits as described herein will not infringe on existing patent rights.
15
LT6559 TYPICAL APPLICATION
DC1063A Demo Circuit Schematic
JP1 ENABLE 2mm RED C10 100nF C11 4.7F E1 5V
C1 22F
R4 3.32k
R10 301 16
12
14 13 R16 75
C7 220F
1 2 3
C4 22F
R11 301 C2 22F
R2 78.7
R7 3.32k
C5 22F
R13 301 C3 22F
HD-15-M
HD-15-F
RELATED PARTS
PART NUMBER LT1203/LT1205 LT1204 LT1399 LT1675/LT1675-1 LT1806/LT1807 LT1809/LT1810 LT6550/LT6551 LT6553 LT6554 LT6555 LT6556 LT6557 LT6558 DESCRIPTION 150MHz Video Multiplexers 4-Input Video MUX with Current Feedback Amplifier 300MHz Triple Current Feedback Amplifier Triple/Single 2:1 Buffered Video Mulitplexer Single/Dual 325MHz Rail-to-Rail In/Out Op Amp Single/Dual 180MHz Rail-to-Rail In/Out Op Amp 3.3V Triple and Quad Video Buffers 650MHz Gain of 2 Triple Video Amplifier 650MHz Gain of 1 Triple Video Amplifier 650MHz Gain of 2 Triple 2:1 Video Multiplexor 750MHz Gain of 1 Triple 2:1 Video Multiplexor Same Pinout as the LT6553 but Optimized for High Impedance Loads 500MHz Gain of 2 Single-Supply Triple Video Amplifier Optimized for Single 5V Supply, 2200V/s Slew Rate, Input Bias Control 550MHz Gain of 1 Single-Supply Triple Video Amplifier Optimized for Single 5V Supply, 2200V/s Slew Rate, Input Bias Control
6559f LT 0606 * PRINTED IN USA
COMMENTS 2:1 and Dual 2:1 MUXs with 25ns Switch Time Cascadable Enable 64:1 Multiplexing 400MHz Bandwidth, 0.1dB Flatness >100MHz 0.1dB Gain Flatness to 150MHz, Shutdown 2.5ns Switching Time, 250MHz Bandwidth Low Distortion, Low Noise Low Distortion, Low Noise 110MHz Gain of 2 Buffers in MS Package Same Pinout as the LT6553 but Optimized for High Impedance Loads
LT1395/LT1396/LT1397 Single/Dual/Quad Current Feedback Amplifiers
16 Linear Technology Corporation
(408) 432-1900 FAX: (408) 434-0507
1630 McCarthy Blvd., Milpitas, CA 95035-7417
www.linear.com
(c) LINEAR TECHNOLOGY CORPORATION 2006
6559 TA03
VIDEO IN J1 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
R3 78.7
R9 3.32k
C6 22F
R15 301
H SYNC V SYNC
+
-
6
+
-
2
9
R8 3.32k
R14 301 12 5
7 8 VIDEO OUT J2 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
U1:C LT6559
+
+
-
9 R6 3.32k R12 301 3 E2 GROUND 12 11 10 R17 75 C8 220F GREEN U1:B LT6559 9 R18 75 C9 220F BLUE
R1 78.7
R5 3.32k
15
+
+
U1:A LT6559
+

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