LT6555
650MHz Gain of 2 Triple
2:1Video Multiplexer
FEATURES
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DESCRIPTIO
650MHz –3dB Small Signal Bandwidth
450MHz –3dB 2V
P-P
Large-Signal Bandwidth
120MHz
±0.1dB
Bandwidth
High Slew Rate: 2200V/µs
Fixed Gain of 2; No External Resistors Required
72dB Channel Separation at 10MHz
50dB Channel Separation at 100MHz
–80dBc 2nd Harmonic Distortion at 10MHz, 2V
P-P
–70dBc 3rd Harmonic Distortion at 10MHz, 2V
P-P
Low Supply Current: 9mA per Amplifier
6.5ns 0.1% Settling Time for 2V Step
I
SS
≤
500µA per Amplifier when Disabled
Differential Gain of 0.033%, Differential
Phase of 0.022°
Wide Supply Range:
±2.25V
(4.5V) to
±6V
(12V)
Available in 24-Lead SSOP and 24-Lead QFN
Packages
The LT
®
6555 is a high speed triple 2:1 video multiplexer
with an internally fixed gain of 2. The individual amplifiers
are optimized for performance with a double terminated
75Ω video load and feature a –3dB 2V
P-P
bandwidth of
450MHz, making them ideal for driving very high resolu-
tion video signals. Separate power supply pins for each
amplifier boost channel separation to 72dB, allowing the
LT6555 to excel in many high speed applications.
While the performance of the LT6555 is optimized for dual
supply operation, it can also be operated with a single
supply as low as 4.5V. Using dual 5V supplies, each
amplifier draws only 9mA. When disabled, the amplifiers
draw less than 500µA and the outputs become high
impedance.
The LT6555 is manufactured on Linear Technology’s
proprietary low voltage complementary bipolar process
and is available in 24-lead SSOP and ultra-compact
24-lead QFN packages.
, LTC and LT are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
APPLICATIO S
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RGB Amplifiers
UXGA Video Multiplexing
LCD Projectors
TYPICAL APPLICATIO
R
INA
G
INA
B
INA
LT6555
75Ω
×2
75Ω
RGB Multiplexer and Line Driver
V
+
75Ω
R
OUT
75Ω
Video Amplitude Transient Response
1.8
1.6
1.4
1.2
75Ω AGND
×2
R
INB
G
INB
B
INB
G
OUT
75Ω
OUTPUT (V)
75Ω
1.0
0.8
0.6
0.4
0.2
0
V
IN
= 0V TO 700mV
V
S
=
±5V
R
L
= 150Ω
T
A
= 25°C
0
2
4
6
8 10 12 14 16 18 20
TIME (ns)
6555 G21
75Ω
75Ω
×2
75Ω
B
OUT
75Ω
SELECT A/B
–0.2
–0.4
75Ω
ENABLE
DGND
V
–
6555 TA01a
U
6555f
U
U
1
LT6555
ABSOLUTE
AXI U RATI GS
Total Supply Voltage (V
+
to V
–
) ............................ 12.6V
Input Current (Note 2) ........................................
±10mA
Output Current (Continuous) .............................
±70mA
EN to DGND Voltage (Note 2) ................................. 5.5V
SEL to DGND Voltage (Note 2) .................................. 8V
Output Short-Circuit Duration (Note 3) ............ Indefinite
Operating Temperature Range (Note 4) ... –40°C to 85°C
Specified Temperature Range (Note 5) .... –40°C to 85°C
PACKAGE/ORDER I FOR ATIO
TOP VIEW
IN1A
DGND
IN2A
V
REF
IN3A
AGND1
IN1B
AGND2
IN2B
1
2
3
4
5
6
7
8
9
G = +2
G = +2
G = +2
23 EN
22 SEL A/B
21 V
+
20 OUT1
19
V
–
LT6555CGN
LT6555IGN
EN
V
+
24 V
+
SEL A/B
DGND
IN2A
IN1A
ORDER PART
NUMBER
V
REF
1
IN3A 2
AGND1 3
V
–
4
IN1B 5
AGND2 6
18 OUT2
17 V
+
16 OUT3
15 V
–
14 V
+
13 V
+
V
+
IN2B
AGND3
IN3B
V
V
AGND3 10
IN3B 11
V
–
12
GN PACKAGE
24-LEAD PLASTIC SSOP
+
–
T
JMAX
= 150°C,
θ
JA
= 90°C/W
Consult LTC Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container.
The
●
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
S
=
±5V,
R
L
= 150Ω, C
L
= 1.5pF, V
EN
= 0.4V, V
AGND
, V
DGND
, V
VREF
= 0V.
SYMBOL
V
OS
I
IN
R
IN
C
IN
PSRR
I
PSRR
A
V
ERR
A
V
MATCH
V
OUT
PARAMETER
Input Referred Offset Voltage
Input Current
Input Resistance
Input Capacitance
Power Supply Rejection Ratio
Input Current Power Supply Rejection
Gain Error
Gain Matching
Output Voltage Swing
V
IN
=
±1V
f = 100kHz
V
S
=
±2.25V
to
±6V
(Note 6)
V
S
=
±2.25V
to
±6V
(Note 6)
V
OUT
=
±2V,
Nominal Gain 2V/V
Any One Channel to Another
(Note 7)
●
●
●
●
ELECTRICAL CHARACTERISTICS
CONDITIONS
V
IN
= 0V, V
OS
= V
OUT
/2
●
●
●
2
U
U
W
W W
U
W
(Note 1)
Junction Temperature
SSOP ................................................................ 150°C
QFN .................................................................. 125°C
Storage Temperature Range
SSOP ................................................. –65°C to 150°C
QFN ................................................... –65°C to 125°C
Lead Temperature (Soldering, 10 sec)
SSOP ................................................................ 300°C
TOP VIEW
ORDER PART
NUMBER
18 V
+
24 23 22 21 20 19
LT6555CUF
LT6555IUF
25
17 OUT1
16 V–
15 OUT2
14 V
+
13 OUT3
7
8
9 10 11 12
UF PART*
MARKING
6555
UF PACKAGE
24-LEAD (4mm
×
4mm) PLASTIC QFN
T
JMAX
= 125°C,
θ
JA
= 37°C/W,
θ
JC
= 2.6°C/W
EXPOSED PAD (PIN 25) IS V
–
MUST BE SOLDERED TO PCB
MIN
TYP
5
–17
MAX
±16
±24
±45
UNITS
mV
mV
µA
kΩ
pF
dB
100
56
400
1
62
1
±0.33
±4
±2.5
µA/V
%
%
V
V
6555f
±3.15
±3.0
±3.4
LT6555
The
●
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
S
=
±5V,
R
L
= 150Ω, C
L
= 1.5pF, V
EN
= 0.4V, V
AGND
, V
DGND
, V
VREF
= 0V.
SYMBOL
I
S
PARAMETER
Supply Current, Per Amplifier
Supply Current, Disabled, Per Amplifier
I
EN
I
SEL
I
SC
SR
–3dB BW
0.1dB BW
FPBW
Enable Pin Current
Select Pin Current
Output Short-Circuit Current
Slew Rate
Small-Signal –3dB Bandwidth
Gain Flatness
±0.1dB
Bandwidth
Full Power Bandwidth 2V
Full Power Bandwidth 4V
All-Hostile Crosstalk
Selected Channel to Unselected
Channel Crosstalk
Channel Select Output Transient
Channel-to-Channel Select Time
t
S
t
R
, t
F
dG
dP
HD2
HD3
Settling Time
Small-Signal Rise and Fall Time
Differential Gain
Differential Phase
2nd Harmonic Distortion
3rd Harmonic Distortion
CONDITIONS
R
L
=
∞
●
ELECTRICAL CHARACTERISTICS
MIN
TYP
9
MAX
12
14
500
500
UNITS
mA
mA
µA
µA
µA
µA
µA
µA
mA
V/µs
MHz
MHz
MHz
MHz
dB
dB
dB
dB
mV
P-P
ns
ns
ps
%
Deg
dBc
dBc
V
EN
= 4V, R
L
=
∞
V
EN
= Open, R
L
=
∞
V
EN
= 0.4V
V
EN
= 4V
V
SEL
= 0.4V
V
SEL
= 4V
R
L
= 0Ω, V
IN
=
±1V
±1V
on
±2.5V
Output Step (Note 8)
V
OUT
= 200mV
P-P
V
OUT
= 200mV
P-P
V
OUT
= 2V
P-P
(Note 9)
V
OUT
= 4V
P-P
(Note 9)
f = 10MHz, V
IN
= 1V
P-P
f = 100MHz, V
IN
= 1V
P-P
f = 10MHz, V
IN
= 1V
P-P
f = 100MHz, V
IN
= 1V
P-P
INA = INB = 0V
INA = –1V, INB = 1V
from 50% SEL to V
OUT
= 0V
0.1% of V
FINAL
, V
STEP
= 2V
10% to 90%, V
OUT
= 400mV
P-P
(Note 10)
(Note 10)
f = 10MHz, V
OUT
= 2V
P-P
f = 10MHz, V
OUT
= 2V
P-P
●
●
●
●
●
●
●
47
42
–200
–75
–50
–50
±50
1600
–95
–21
–5
–1
±105
2200
650
120
250
350
175
–72
–50
–80
–55
200
8
6.5
520
0.033
0.022
–80
–70
Note 1:
Absolute Maximum Ratings are those values beyond which the life
of a device may be impaired.
Note 2:
This parameter is guaranteed to meet specified performance
through design and characterization. It is not production tested.
Note 3:
As long as output current and junction temperature are kept below
the Absolute Maximum Ratings, no damage to the part will occur.
Depending on the supply voltage, a heat sink may be required.
Note 4:
The LT6555C is guaranteed functional over the operating
temperature range of –40°C to 85°C.
Note 5:
The LT6555C is guaranteed to meet specified performance from
0°C to 70°C. The LT6555C is designed, characterized and expected to
meet specified performance from –40°C and 85°C but is not tested or QA
sampled at these temperatures. The LT6555I is guaranteed to meet
specified performance from –40°C to 85°C.
Note 6:
In order to follow the constraints for 4.5V operation for PSRR
and I
PSRR
testing at
±2.25V,
the DGND pin is set to V
–
, the EN pin is set
to V
–
+ 0.4V, and the SEL pin is set to either V
–
+ 0.4V or V
–
+ 4V. At
±6V
and all other cases, DGND is set to ground and the EN and SEL pins are
referenced from it.
Note 7:
The V
REF
pin is set to 1V when testing positive swing and –1V
when testing negative swing to ensure that the internal input clamps do
not limit the output swing.
Note 8:
Slew rate is 100% production tested using both inputs of
channel 2. Slew rates of channels 1 and 3 are guaranteed through
design and characterization.
Note 9:
Full power bandwidth is calculated from the slew rate:
FPBW = SR/(π • V
P-P
)
Note 10:
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 better than 0.05%
and 0.05°. Nine identical amplifier stages were cascaded giving an
effective resolution of better than 0.0056% and 0.0056%.
6555f
3
LT6555
TYPICAL PERFOR A CE CHARACTERISTICS
Supply Current per Amplifier
vs Temperature
12
10
SUPPLY CURRENT (mA)
SUPPLY CURRENT (mA)
SUPPLY CURRENT (mA)
V
EN
= 0V
V
EN
= 0.4V
8
6
4
2
V
EN
= 4V
0
–55 –35 –15
5 25 45 65 85 105 125
TEMPERATURE (°C)
6555 G01
Input Referred Offset Voltage
vs Temperature
15
10
V
S
=
±5V
V
IN
= 0V
INPUT BIAS CURRENT (µA)
OFFSET VOLTAGE (mV)
EN PIN CURRENT (µA)
5
0
–5
–10
–15
–55 –35 –15
5 25 45 65 85 105 125
TEMPERATURE (°C)
6555 G04
Maximum Output Voltage Swing
vs V
REF
Pin Voltage
4
3
T
A
= –55°C
HIGH SWING
OUTPUT VOLTAGE (V)
T
A
= 25°C
T
A
= 125°C
4
5
OUTPUT VOLTAGE (V)
OUTPUT VOLTAGE (V)
2
1
0
–1
–2
–3 LOW SWING
–4
V
S
=
±5V
R
L
= 150Ω
T
A
= 125°C
T
A
= 25°C
T
A
= –55°C
–2 –1.5 –1 –0.5 0 0.5 1
V
REF
PIN VOLTAGE (V)
1.5
2
0
0
10 20 30 40 50 60 70 80 90 100
SOURCE CURRENT (mA)
6555 G08
4
U W
V
S
=
±5V
R
L
=
∞
V
IN
= 0V
6555 G07
Supply Current per Amplifier
vs Supply Voltage
12
10
8
6
4
2
0
V
EN
, V
IN
, V
DGND
, V
SEL
= 0V
T
A
= 25°C
12
10
Supply Current per Amplifier
vs EN Pin Voltage
V
S
=
±5V
R
L
=
∞
V
IN
= 0V
T
A
= –55°C
8
T
A
= 25°C
6
T
A
= 125°C
4
2
0
0
1
2
3 4 5 6 7 8 9 10 11 12
TOTAL SUPPLY VOLTAGE (V)
6555 G02
0
0.5
1.0 1.5 2.0 2.5 3.0
EN PIN VOLTAGE (V)
3.5
4.0
6555 G03
Input Bias Current
vs Temperature
0
–5
–10
–15
–20
V
IN
= –1.5V
–25
–30
–35
–40
–55 –35 –15
5 25 45 65 85 105 125
TEMPERATURE (°C)
6555 G05
EN Pin Current vs EN Pin Voltage
0
–20
V
S
=
±5V
V
DGND
= 0V
V
S
=
±5V
V
IN
= 0V
V
IN
= 1.5V
–40
–60
–80
T
A
= 25°C
–100
–120
–140
0
1
3
2
EN PIN VOLTAGE (V)
4
5
6555 G06
T
A
= 125°C
T
A
= –55°C
Output Voltage Swing
vs I
LOAD
(Output High)
V
REF
INPUT
CLAMPING
V
S
=
±5V
V
IN
= 2V
V
VREF
= 0V
Output Voltage Swing
vs I
LOAD
(Output Low)
0
V
S
=
±5V
V
IN
= –2V
V
VREF
= 0V
T
A
= 125°C
T
A
= 25°C
T
A
= –55°C
–2
–1
3
2
T
A
= 125°C
1
T
A
= 25°C
T
A
= –55°C
–3
–4
V
REF
INPUT
CLAMPING
–5
0
10 20 30 40 50 60 70 80 90 100
SINK CURRENT (mA)
6555 G09
6555f
LT6555
TYPICAL PERFOR A CE CHARACTERISTICS
Input Noise Spectral Density
INPUT NOISE VOLTAGE (nV/√Hz OR pA/√Hz)
1000
V
S
=
±5V
T
A
= 25°C
1000
POWER SUPPLY REJECTION RATIO (dB)
INPUT IMPEDANCE (kΩ)
100
i
n
10
e
n
1
0.001
0.01
0.1
1
FREQUENCY (kHz)
Frequency Response
vs Output Amplitude
9
8
7
6
V
S
=
±5V
R
L
= 150Ω
T
A
= 25°C
NORMALIZED GAIN (dB)
GAIN (dB)
GAIN (dB)
5
4
3
2
1
0
0.1
1
10
100
FREQUENCY (MHz)
1000
6555 G13
V
OUT
= 200mV
P-P
V
OUT
= 2V
P-P
V
OUT
= 4V
P-P
Crosstalk vs Frequency
V
S
=
±5V
V
OUT
= 2V
P-P
–20 R
L
= 150Ω
T
A
= 25°C
AMPLITUDE (dB)
AMPLITUDE (dB)
–40
–60
–80
0
0
–40
–60
–80
DRIVE IN A,
SELECT IN B
DRIVE IN B,
SELECT IN A
DISTORTION (dBc)
WORST
ADJACENT
ALL
CHANNELS
DRIVEN
–100
–120
0.1
1
10
100
FREQUENCY (MHz)
U W
10
6555 G10
6555 G16
Input Impedance vs Frequency
V
S
=
±5V
V
IN
= 0V
T
A
= 25°C
70
60
Input Referred PSRR
vs Frequency
±PSRR
+PSRR
50
40
30
20
10
0
0.001
–PSRR
V
S
=
±5V
T
A
= 25°C
100
10
1
100
0.1
0.01
0.1
1
10
FREQUENCY (MHz)
100
1000
6555 G11
0.01
0.1
1
FREQUENCY (MHz)
10
100
6555 G12
Gain Flatness vs Frequency
6.20
6.15
IN1A
6.10
IN3A
6.05
IN1B
6.00
5.95
IN2B
V
S
=
±5V
V
OUT
= 200mV
P-P
R
L
= 150Ω
T
A
= 25°C
1
10
100
FREQUENCY (MHz)
1000
6555 G14
Frequency Response with
Capacitive Loads
18
16
14
12
10
8
6
4
2
0
–2
–4
–6
0.1
1
10
100
FREQUENCY (MHz)
1000
6555 G15
V
S
=
±5V
V
OUT
= 2V
P-P
R
L
= 150Ω
T
A
= 25°C
C
L
= 10pF
C
L
= 4.7pF
C
L
= 0pF
IN3B
IN2A
5.90
0.1
Crosstalk vs Frequency
V
S
=
±5V
V
IN
= 1V
P-P
–20 R
L
= 150Ω
T
A
= 25°C
Harmonic Distortion vs Frequency
0
–10
–20
–30
–40
–50
–60
–70
–80
–90
–100
–110
–120
0.01
HD3
HD2
V
S
=
±5V
V
OUT
= 2V
P-P
R
L
= 150Ω
T
A
= 25°C
–100
–120
0.1
1000
1
10
100
FREQUENCY (MHz)
1000
6555 G17
0.1
1
10
FREQUENCY (MHz)
100
6555 G18
6555f
5
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