LT6554
650MHz Gain of 1
Triple Video Buffer
FEATURES
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DESCRIPTIO
650MHz –3dB Small Signal Bandwidth
400MHz –3dB 2V
P-P
Large Signal Bandwidth
100MHz
±0.1dB
Bandwidth
High Slew Rate: 2500V/µs
Fixed Gain of 1 Requires No External Resistors
90dB Channel Separation at 10MHz
60dB Channel Separation at 100MHz
–82dBc 2nd Harmonic Distortion at 10MHz, 2V
P-P
–96dBc 3rd Harmonic Distortion at 10MHz, 2V
P-P
Low Supply Current: 8mA per Amplifier
6ns 0.1% Settling Time for 2V Step
TTL Compatible Enable: I
SS
≤
100µA When Disabled
Differential Gain of 0.022%, Differential
Phase of 0.006°
Wide Supply Range:
±2.25V
(4.5V) to
±6V
(12V)
Available in 16-Lead SSOP Package
The LT
®
6554 is a high-speed triple video buffer with an
internally fixed gain of 1. The individual buffers are opti-
mized for performance with a 1k load and feature a
2V
P–P
full signal bandwidth of 400MHz, making them ideal
for driving very high-resolution video signals. Separate
power supply pins for each amplifier boost channel sepa-
ration to 90dB, allowing the LT6554 to excel in many high-
speed applications.
While the performance of the LT6554 is optimized for dual
supply operation, it can also be used on a single supply as
low as 4.5V. Using dual 5V supplies, each amplifier draws
only 8mA. When disabled, the amplifiers draw less than
100µA and the outputs become high impedance. Further-
more, the amplifiers are capable of turning on in less than
50ns, making them suitable for multiplexing and portable
applications.
The LT6554 is manufactured on Linear Technology’s
proprietary low voltage complementary bipolar process
and is available in the 16-lead SSOP package that fits in the
same PCB area as an SO-8 package.
, 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 Buffers
A/D Drivers
LCD Projectors
TYPICAL APPLICATIO
1
2
3
LT6554
Triple Video Buffer and A/D Driver
5V
16
15
Large Signal Transient Response
1.5
V
OUT
= 2V
P–P
V
S
=
±5V
1.0 R
L
= 1k
T
A
= 25°C
0.5
–5V
R
IN
+
–
480Ω
14
1k
480Ω
–
G
IN
5
6
+
480Ω
OUTPUT (V)
4
13
0
–0.5
–1.0
–1.5
12
11
1k
5V
–
B
IN
–5V
7
8
+
10
1k
9
–5V
6554 TA01b
6554 TA01a
0
2
U
4
6
8 10 12 14 16 18 20
TIME (ns)
6554fa
U
U
1
LT6554
ABSOLUTE
(Note 1)
AXI U RATI GS
PACKAGE/ORDER I FOR ATIO
TOP VIEW
EN
DGND
INR
AGND
ING
AGND
INB
V
–
1
2
3
4
5
6
7
8
G = +1
G = +1
G = +1
Total Supply Voltage (V
+
to V
–
) ............................ 13.2V
Input Current (Note 2) ........................................
±10mA
Output Current (Continuous) .............................
±70mA
EN to DGND Voltage (Note 2) ................................. 5.5V
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
Storage Temperature Range .................. –65°C to 150°C
Junction Temperature ........................................... 150°C
Lead Temperature (Soldering, 10 sec).................. 300°C
16 V
+
15 V
+
14 OUTR
13 V
–
12 OUTG
11 V
+
10 OUTB
9
V
–
ORDER PART
NUMBER
LT6554CGN
LT6554IGN
GN PART
MARKING
6554
6554I
GN PACKAGE
16-LEAD PLASTIC SSOP
T
JMAX
= 150°C,
θ
JA
= 135°C/W
Consult LTC Marketing for parts specified with wider operating temperature ranges.
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
= 1k, C
L
= 1.5pF, V
EN
= 0.4V, V
AGND
, V
DGND
= 0V.
SYMBOL
V
OS
I
IN
e
n
i
n
R
IN
C
IN
PSRR
I
PSRR
A
V
ERR
A
V
MATCH
V
OUT
I
S
PARAMETER
Offset Voltage
Input Current
Output Noise Voltage
Input Noise Current
Input Resistance
Input Capacitance
Power Supply Rejection Ratio
Input Current Power Supply
Rejection
Gain Error
Gain Matching
Maximum Output Voltage Swing
Supply Current, Per Amplifier
Supply Current, Disabled, Total
I
EN
I
SC
SR
–3dB BW
0.1dB BW
Enable Pin Current
Output Short-Circuit Current
Slew Rate
Small Signal –3dB Bandwidth
Gain Flatness
±0.1dB
Bandwidth
R
L
=
∞
R
L
=
∞
V
EN
= 4V
V
EN
= Open
V
EN
= 0.4V
V
EN
= V
+
R
L
= 0Ω, V
IN
=
±2V
4V
P-P
Output Step (Note 9)
V
OUT
= 200mV
P-P
V
OUT
= 200mV
P-P
f = 100kHz
f = 100kHz
V
IN
=
±1V
f = 100kHz
V
S
(Total) = 4.5V to 12V (Note 6)
V
S
(Total) = 4.5V to 12V (Note 6)
V
OUT
=
±2V
Any One Channel to Another
●
●
●
●
●
●
●
●
●
●
●
ELECTRICAL CHARACTERISTICS
CONDITIONS
V
IN
= 0V, V
OS
= V
OUT
●
●
MIN
TYP
11
–17
20
3.5
MAX
±35
±70
±50
UNITS
mV
mV
µA
nV√Hz
pA√Hz
kΩ
pF
dB
150
51
400
1
65
1
±5
0
µA/V
%
%
V
–2.5
±3.75
–0.6
±0.03
±3.85
8
22
0.5
10
13
100
100
50
–200
±50
1700
–95
0.5
±105
2500
650
100
6554fa
2
U
mA
mA
µA
µA
µA
µA
mA
V/µs
MHz
MHz
W
U
U
W W
W
LT6554
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
= 1k, C
L
= 1.5pF, V
EN
= 0.4V, V
AGND
, V
DGND
= 0V.
SYMBOL
LSBW
PARAMETER
Large Signal Bandwidth
All-Hostile Crosstalk
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
V
OUT
= 2V
P-P
(Note 7)
V
OUT
= 4V
P-P
(Note 7)
f = 10MHz, V
OUT
= 2V
P-P
f = 100MHz, V
OUT
= 2V
P-P
0.1% of V
FINAL
, V
STEP
= 2V
10% to 90%, V
OUT
= 200mV
P-P
(Note 8)
(Note 8)
f = 10MHz, V
OUT
= 2V
P-P
f = 10MHz, V
OUT
= 2V
P-P
MIN
270
TYP
400
200
–90
–60
6
550
0.022
0.006
–82
–96
MAX
UNITS
MHz
MHz
dB
dB
ns
ps
%
Deg
dBc
dBc
ELECTRICAL CHARACTERISTICS
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 LT6554C is guaranteed functional over the operating
temperature range of –40°C to 85°C.
Note 5:
The LT6554C is guaranteed to meet specified performance from
0°C to 70°C. The LT6554C 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 LT6554I is guaranteed to meet
specified performance from –40°C to 85°C.
Note 6:
The two supply voltage settings for power supply rejection are
shifted from the typical
±V
S
points for ease of testing. The first
measurement is taken at V
+
= 3V, V
–
= –1.5V to provide the required 3V
headroom for the enable circuitry to function with EN, DGND, AGND and
all inputs connected to 0V. The second measurement is taken at V
+
= 8V,
V
–
= –4V.
Note 7:
Large signal bandwidth is calculated from the slew rate:
LSBW = SR/(π • V
P-P
)
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 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°.
Note 9:
Slew rate is 100% production tested on the G channel. Slew rate
of the R and B channels is guaranteed through design and
characterization.
6554fa
3
LT6554
TYPICAL PERFOR A CE CHARACTERISTICS
Supply Current per Amplifier vs
Temperature
12
10
V
S
=
±5V
R
L
=
∞
V
IN
= 0V
12
SUPPLY CURRENT (mA)
SUPPLY CURRENT (mA)
SUPPLY CURRENT (mA)
V
EN
= 0V
8
6
4
2
0
–55 –35 –15
V
EN
= 0.4V
5 25 45 65 85 105 125
TEMPERATURE (°C)
6554 G01
Offset Voltage vs Temperature
15.0
12.5
V
S
=
±5V
V
IN
= 0V
TYPICAL PART
20
INPUT BIAS CURRENT (µA)
OFFSET VOLTAGE (mV)
EN PIN CURRENT (µA)
10.0
7.5
5.0
2.5
0
–2.5
–5.0
–55 –35 –15
5 25 45 65 85 105 125
TEMPERATURE (°C)
6554 G04
Output Voltage vs Input Voltage
5
V
S
=
±5V
4 R
L
= 1k
3
5
OUTPUT VOLTAGE (V)
OUTPUT VOLTAGE (V)
2
1
0
–1
–2 T
A
= –55°C
–3
–4
T
A
= 25°C
3
T
A
= –55°C
T
A
= 25°C
OUTPUT VOLTAGE (V)
T
A
= 125°C
–5
–4.5 –3.5 –2.5 –1.5 –0.5 0.5 1.5 2.5 3.5 4.5
INPUT VOLTAGE (V)
6554 G07
4
U W
Supply Current per Amplifier vs
Supply Voltage
V
–
= –V
+
V
EN
, V
DGND
, V
IN
= 0V
10 T
A
= 25°C
8
6
4
2
0
12
10
8
6
4
2
0
Supply Current per Amplifier vs
EN Pin Voltage
T
A
= –55°C
T
A
= 25°C
T
A
= 125°C
V
S
=
±5V
V
DGND
= 0V
V
IN
= 0V
0
1
2
3 4 5 6 7 8 9 10 11 12
TOTAL SUPPLY VOLTAGE (V)
6554 G02
0
0.5
1.0 1.5 2.0 2.5 3.0
EN PIN VOLTAGE (V)
3.5
4.0
6554 G03
Input Bias Current vs
Input Voltage
V
S
=
±5V
0
–20
0
T
A
= 125°C
–20
–40
–60
–80
EN Pin Current vs EN Pin Voltage
V
S
=
±5V
V
DGND
= 0V
T
A
= 125°C
T
A
= –55°C
T
A
= 25°C
T
A
= 25°C
T
A
= –55°C
–40
–100
–120
–60
–2.5
–1.5
0.5
1.5
–0.5
INPUT VOLTAGE (V)
2.5
6554 G05
–140
0
1
3
2
EN PIN VOLTAGE (V)
4
5
6554 G06
Output Voltage Swing vs I
LOAD
(Output High)
V
S
=
±5V
V
IN
= 4V
0
Output Voltage Swing vs I
LOAD
(Output Low)
V
S
=
±5V
V
IN
= –4V
T
A
= 25°C
–2
T
A
= 125°C
–3
T
A
= –55°C
4
–1
2
T
A
= 125°C
1
–4
0
0
10 20 30 40 50 60 70 80 90 100
SOURCE CURRENT (mA)
6554 G08
–5
0
10 20 30 40 50 60 70 80 90 100
SINK CURRENT (mA)
6554 G09
6554fa
LT6554
TYPICAL PERFOR A CE CHARACTERISTICS
Input Noise Spectral Density
1000
INPUT NOISE (nV/√Hz OR pA/√Hz)
V
S
=
±5V
T
A
= 25°C
INPUT IMPEDANCE (kΩ)
1000
100
e
n
REJECTION RATIO (dB)
10
i
n
1
0.001
0.01
0.1
1
FREQUENCY (kHz)
10
100
6554 G10
Frequency Response
3
V
S
=
±5V
2 R
L
= 1k
C
L
= 1.5pF
1 T
A
= 25°C
AMPLITUDE (dB)
0
–1
–2
–3
–4
–5
–6
0.1
1
100
10
FREQUENCY (MHz)
1000
6554 G13
V
OUT
= 200mV
P-P
AMPLITUDE (dB)
AMPLITUDE (dB)
V
OUT
= 2V
P-P
V
OUT
= 4V
P-P
Frequency Response with
Capacitive Loads
12
V
S
=
±5V
10 V
OUT
= 200mV
P-P
R
L
= 1k
8 T
A
= 25°C
AMPLITUDE (dB)
6
4
2
0
–2
–4
–6
0.1
1
100
10
FREQUENCY (MHz)
1000
6554 G16
DISTORTION (dBc)
C
L
= 9pF
C
L
= 6.8pF
C
L
= 3.3pF
C
L
= 1.5pF
OUTPUT IMPEDANCE (Ω)
U W
C
L
= 12pF
Input Impedance vs Frequency
V
S
=
±5V
V
IN
= 0V
T
A
= 25°C
70
60
50
40
30
20
10
0.1
0.01
PSRR vs Frequency
±PSRR
+PSRR
–PSRR
V
S
=
±5V
T
A
= 25°C
100
10
1
0.1
1
10
FREQUENCY (MHz)
100
1000
6554 G11
0
0.001
0.01
0.1
1
FREQUENCY (MHz)
10
100
6554 G12
Gain Flatness vs Frequency
0.5
V
S
=
±5V
0.4 V
OUT
= 200mV
P-P
R
L
= 1k
0.3 C = 1.5pF
L
0.2 T
A
= 25°C
TYPICAL PART
0.1
0
– 0.1
– 0.2
– 0.3
– 0.4
– 0.5
0.1
1
10
100
FREQUENCY (MHz)
1000
6554 G14
Crosstalk vs Frequency
0
– 20
V
S
=
±5V
V
OUT
= 2V
P-P
R
L
= 1k
T
A
= 25°C
ALL-
HOSTILE
R-CHANNEL
– 40
– 60
– 80
G-CHANNEL
B-CHANNEL
WORST
ADJACENT
– 100
– 120
0.1
1
10
100
FREQUENCY (MHz)
1000
6554 G15
Harmonic Distortion vs Frequency
V
S
=
±5V
–10 V
OUT
= 2V
P-P
–20 R
L
= 1k
T = 25°C
–30
A
–40
–50
–60
–70
–80
–90
–100
–110
–120
0.01
0.1
1
10
FREQUENCY (MHz)
100
6554 G17
Output Impedance vs Frequency
100000
10000
1000
100
10
1
0.1
0.01
DISABLED
V
EN
= 4V
V
S
=
±5V
R
L
= 1k
T
A
= 25°C
0
HD2
HD3
ENABLED
V
EN
= 0.4V
0.1
1
10
100
FREQUENCY (MHz)
1000
6554 G18
6554fa
5
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