MAX4090AAUT+ [MAXIM]
Video Amplifier;
| 型号： | MAX4090AAUT+ |
| 厂家： | 
MAXIM INTEGRATED PRODUCTS |
| 描述： | Video Amplifier |
| 文件： | 总12页 (文件大小：651K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
19-2813; Rev 2; 8/04
3V/5V, 6dB Video Buffer with Sync-Tip Clamp
and 150nA Shutdown Current
General Description
Features
The MAX4090 3V/5V, 6dB video buffer with sync-tip
clamp, and low-power shutdown mode is available in
tiny SOT23 and SC70 packages. The MAX4090 is
designed to drive DC-coupled, 150Ω back-terminated
video loads in portable video applications such as digi-
tal still cams, portable DVD players, digital camcorders,
PDAs, video-enabled cell phones, portable game sys-
tems, and notebook computers. The input clamp posi-
tions the video waveform at the output and allows the
MAX4090 to be used as a DC-coupled output driver.
♦ Single-Supply Operation from 2.7V to 5.5V
♦ Input Sync-Tip Clamp
♦ DC-Coupled Output
♦ Low-Power Shutdown Mode Reduces Supply
Current to 150nA
♦ Available in Space-Saving SOT23 and SC70
Packages
The MAX4090 operates from a single 2.7V to 5.5V sup-
ply and consumes only 6.5mA of supply current. The
low-power shutdown mode reduces the supply current
to 150nA, making the MAX4090 ideal for low-voltage,
battery-powered video applications.
The MAX4090 is available in tiny 6-pin SOT23 and
SC70 packages and is specified over the extended
-40°C to +85°C temperature range.
Applications
Ordering Information
Portable Video/Game Systems/DVD Players
Digital Camcorders/Televisions/Still Cameras
PDAs
PIN-
PACKAGE
TOP
MARK
PART
TEMP RANGE
MAX4090EXT-T
MAX4090EUT-T
-40°C to +85°C 6 SC70-6
-40°C to +85°C 6 SOT23-6
ABM
ABOX
Video-Enabled Cell Phones
Notebook Computers
Portable/Flat-Panel Displays
Block Diagram
Pin Configuration
TOP VIEW
IN
V
CC
TOP VIEW
MAX4090
OUT
GND
IN
1
2
3
6
5
4
FB
OUT
MAX4090
SHDN
2.3kΩ
CLAMP
FB
V
CC
580Ω
780Ω
1.2kΩ
SC70/SOT23
SHDN
GND
________________________________________________________________ Maxim Integrated Products
1
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.
3V/5V, 6dB Video Buffer with Sync-Tip Clamp
and 150nA Shutdown Current
ABSOLUTE MAXIMUM RATINGS
CC
OUT, FB, SHDN to GND............................ -0.3V to (V
V
to GND............................................................. -0.3V to +6V
Operating Temperature Range ..........................-40°C to +85°C
Junction Temperature .....................................................+150°C
Storage Temperature Range ............................-65°C to +150°C
Lead Temperature (soldering, 10s) ................................+300°C
+ 0.3V)
+ 0.3V)
CC
CC
IN to GND (Note 1) ................................... V
to (V
CLP
IN Short-Circuit Duration from -0.3V to V
........................1min
CLP
Output Short-Circuit Duration to V
or GND .......... Continuous
CC
Continuous Power Dissipation (T = +70°C)
A
6-Pin SOT23 (derate 8.7mW/°C above +70°C) ...........695mW
6-Pin SC70 (derate 3.1mW/°C above +70°C) .............245mW
Note 1: V
is the input clamp voltage as defined in the DC Electrical Characteristics table.
CLP
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
(V
= 3.0V, GND = 0V, C = 0.1µF from IN to GND, R = infinity to GND, FB shorted to OUT, SHDN = 3.0V, T = -40°C to +85°C.
IN L A
CC
Typical values are at T = +25°C, unless otherwise noted.) (Note 2)
A
PARAMETER
SYMBOL
CONDITIONS
Guaranteed by PSRR
MIN
TYP
MAX
5.5
10
UNITS
Supply Voltage Range
V
2.7
V
CC
V
V
= 3V
= 5V
6.5
6.5
CC
CC
Quiescent Supply Current
I
V
= V
mA
CC
IN
CLP
10
Shutdown Supply Current
Input Clamp Voltage
Input Voltage Range
Input Bias Current
I
SHDN = 0V
0.15
0.38
1
µA
V
SHDN
V
Input referred
0.27
0.47
1.45
35
CLP
V
Inferred from voltage gain (Note 3)
V
V
IN
CLP
I
V
V
= 1.45V
22.5
3
µA
MΩ
V/V
dB
BIAS
IN
Input Resistance
+ 0.5V < V < V
+ 1V
CLP
CLP
IN
Voltage Gain
A
R = 150Ω, 0.5V < V < 1.45V (Note 4)
L
1.9
60
2
2.1
V
IN
Power-Supply Rejection Ratio
PSRR
2.7V < V
< 5.5V
80
2.7
4.6
CC
V
V
= 3V
= 5V
2.55
4.3
CC
CC
Output Voltage High Swing
Output Voltage Low Swing
Output Current
V
R = 150Ω to GND
L
V
V
OH
V
R = 150Ω to GND
L
V
0.47
OL
CLP
Sourcing, R = 20Ω to GND
45
40
85
L
I
mA
OUT
Sinking, R = 20Ω to V
85
L
CC
Output Short-Circuit Current
SHDN Logic-Low Threshold
SHDN Logic-High Threshold
SHDN Input Current
I
OUT shorted to V
or GND
110
mA
V
SC
CC
V
V
x 0.3
CC
IL
IH
IH
V
V
x 0.7
V
CC
I
0.003
4
1
µA
At DC
R
OUT
(Disabled)
Shutdown Output Impedance
SHDN = 0V
kΩ
At 3.58MHz or
4.43MHz
2
2
_______________________________________________________________________________________
3V/5V, 6dB Video Buffer with Sync-Tip Clamp
and 150nA Shutdown Current
AC ELECTRICAL CHARACTERISTICS
(V
= 3.0V, GND = 0V, FB shorted to OUT, C = 0.1µF, R = 75Ω to GND, R = 150Ω to GND, SHDN = V , T = +25°C, unless
CC
IN
IN
L
CC
A
otherwise noted.)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
MHz
MHz
MHz
MHz
V/µs
ns
Small-Signal -3dB Bandwidth
Large-Signal -3dB Bandwidth
BW
BW
V
V
V
V
V
V
= 100mV
55
45
25
17
275
25
50
2.5
1
SS
LS
OUT
OUT
OUT
OUT
OUT
OUT
P-P
= 2V
P-P
Small-Signal 0.1dB Gain Flatness BW
Large-Signal 0.1dB Gain Flatness BW
Slew Rate
= 100mV
P-P
0.1dBSS
= 2V
0.1dBLS
SR
P-P
= 2V step
= 2V step
Settling Time to 0.1%
t
S
Power-Supply Rejection Ratio
Output Impedance
PSRR
f = 100kHz
f = 5MHz
dB
Z
Ω
OUT
V
V
V
V
= 3V
= 5V
= 3V
= 5V
CC
CC
CC
CC
Differential Gain
Differential Phase
DG
DP
NTSC
NTSC
%
0.5
0.8
0.5
20
65
2
Degrees
Group Delay
D/dT
SNR
f = 3.58MHz or 4.43MHz
ns
dB
%
Peak Signal to RMS Noise
Droop
V
= 1V , 10MHz BW
P-P
IN
C
= 0.1µF (Note 4)
3
IN
V
= V
+ 1V, SHDN = 3V, V
settled
settled
IN
CLP
OUT
OUT
SHDN Enable Time
SHDN Disable Time
t
250
50
ns
ns
ON
to within 1% of the final voltage
V
= V + 1V, SHDN = 0V, V
IN
CLP
t
OFF
to below 1% of the output voltage
Note 2: All devices are 100% production tested at T = +25°C. Specifications over temperature limits are guaranteed by design.
A
Note 3: Voltage gain (A ) is referenced to the clamp voltage, i.e., an input voltage of V = V + VI would produce an output volt-
V
IN
CLP
age of V
= V
+ A x VI.
CLP V
OUT
Note 4: Droop is guaranteed by the Input Bias Current specification.
_______________________________________________________________________________________
3
3V/5V, 6dB Video Buffer with Sync-Tip Clamp
and 150nA Shutdown Current
Typical Operating Characteristics
(V
= 3.0V, GND = 0V, FB shorted to OUT, C = 0.1µF, R = 75Ω to GND, R = 150Ω to GND, SHDN = V , T = +25°C, unless
IN IN L CC A
CC
otherwise noted.)
SMALL-SIGNAL GAIN
vs. FREQUENCY
SMALL-SIGNAL GAIN FLATNESS
vs. FREQUENCY
SMALL-SIGNAL GAIN
vs. FREQUENCY
3
2
0.3
3
2
0.2
0.1
1
1
0
0
0
-1
-2
-3
-4
-5
-6
-0.1
-0.2
-0.3
-0.4
-0.5
-0.6
-1
-2
-3
-4
-5
-6
A
V
V
= 2
A
V
V
= 2
A
V
V
= 2
V
V
V
= 3V
= 3V
= 5V
CC
CC
CC
= 100mV
= 100mV
= 100mV
OUT
P-P
OUT
P-P
OUT
P-P
100k
1M
10M
100M
100k
1M
10M
100M
100k
1M
10M
100M
FREQUENCY (Hz)
FREQUENCY (Hz)
FREQUENCY (Hz)
SMALL-SIGNAL GAIN FLATNESS
vs. FREQUENCY
LARGE-SIGNAL GAIN
vs. FREQUENCY
LARGE-SIGNAL GAIN FLATNESS
vs. FREQUENCY
0.3
0.2
3
2
0.3
0.2
0.1
1
0.1
0
0
0
-0.1
-0.2
-0.3
-0.4
-0.5
-0.6
-1
-2
-3
-4
-5
-6
-0.1
-0.2
-0.3
-0.4
-0.5
-0.6
A
V
V
= 2
A
V
V
= 2
A
V
V
= 2
V
V
V
= 5V
= 3V
= 3V
CC
OUT
CC
OUT
CC
OUT
= 100mV
= 2V
= 2V
P-P
P-P
P-P
100k
1M
10M
100M
100k
1M
10M
100M
100k
1M
10M
100M
FREQUENCY (Hz)
FREQUENCY (Hz)
FREQUENCY (Hz)
LARGE-SIGNAL GAIN
vs. FREQUENCY
LARGE-SIGNAL GAIN FLATNESS
vs. FREQUENCY
POWER-SUPPLY REJECTION RATIO
vs. FREQUENCY
3
2
0.3
0.2
0
-10
-20
-30
-40
-50
-60
-70
-80
V
= 3V
CC
1
0.1
0
0
-1
-2
-3
-4
-5
-6
-0.1
-0.2
-0.3
-0.4
-0.5
-0.6
A
V
V
= 2
A
V
V
= 2
V
V
= 5V
= 5V
CC
OUT
CC
OUT
= 2V
= 2V
P-P
P-P
100k
1M
10M
100M
100k
1M
10M
100M
10k
100k
1M
10M
100M
FREQUENCY (Hz)
FREQUENCY (Hz)
FREQUENCY (Hz)
4
_______________________________________________________________________________________
3V/5V, 6dB Video Buffer with Sync-Tip Clamp
and 150nA Shutdown Current
Typical Operating Characteristics (continued)
(V
= 3.0V, GND = 0V, FB shorted to OUT, C = 0.1µF, R = 75Ω to GND, R = 150Ω to GND, SHDN = V , T = +25°C, unless
IN IN L CC A
CC
otherwise noted.)
POWER-SUPPLY REJECTION RATIO
QUIESCENT SUPPLY CURRENT
vs. TEMPERATURE
CLAMP VOLTAGE
vs. TEMPERATURE
vs. FREQUENCY
0
-10
-20
-30
-40
-50
-60
-70
-80
6.80
6.75
6.70
6.65
6.60
6.55
6.50
6.45
6.40
6.35
6.30
0.60
0.55
0.50
0.45
0.40
0.35
0.30
0.25
0.20
V
= 3V
CC
V
= 5V
CC
V
= 5V
CC
V
= 3V
CC
25
10k
100k
1M
10M
100M
-50
-25
0
50
75
100
-50
-25
0
25
50
75
100
FREQUENCY (Hz)
TEMPERATURE (°C)
TEMPERATURE (°C)
CLAMP VOLTAGE
vs. TEMPERATURE
VOLTAGE GAIN vs. TEMPERATURE
VOLTAGE GAIN vs. TEMPERATURE
0.60
0.55
0.50
0.45
0.40
0.35
0.30
0.25
0.20
2.10
2.05
2.00
1.95
1.90
2.10
2.05
2.00
1.95
1.90
V
= 5V
CC
V
= 3V
CC
V
= 5V
CC
-50
-25
0
25
50
75
100
-50
-25
0
25
50
75
100
-50
-25
0
25
50
75
100
TEMPERATURE (°C)
TEMPERATURE (°C)
TEMPERATURE (°C)
OUTPUT VOLTAGE HIGH SWING
vs. TEMPERATURE
OUTPUT VOLTAGE HIGH SWING
vs. TEMPERATURE
LARGE-SIGNAL PULSE RESPONSE
MAX4090 toc18
5.0
4.9
4.8
4.7
4.6
4.5
4.4
4.3
4.2
4.1
4.0
3.0
2.9
2.8
2.7
2.6
2.5
2.4
2.3
2.2
2.1
2.0
V
= 5V
V
= 3V
CC
CC
V
IN
500mV/div
V
OUT
1V/div
-50
-25
0
25
50
75
100
-50
-25
0
25
50
75
100
10ns/div
TEMPERATURE (°C)
TEMPERATURE (°C)
_______________________________________________________________________________________
5
3V/5V, 6dB Video Buffer with Sync-Tip Clamp
and 150nA Shutdown Current
Typical Operating Characteristics (continued)
(V
= 3.0V, GND = 0V, FB shorted to OUT, C = 0.1µF, R = 75Ω to GND, R = 150Ω to GND, SHDN = V , T = +25°C, unless
CC
IN
IN
L
CC
A
otherwise noted.)
SMALL-SIGNAL PULSE RESPONSE
DIFFERENTIAL GAIN AND PHASE
MAX4090 toc19
2.0
1.0
0
V
IN
25mV/div
-1.0
-2.0
0
1
2
3
4
5
6
1.0
0.5
0
V
OUT
50mV/div
-0.5
-1.0
0
1
2
3
4
5
6
10ns/div
Typical Application Circuit
Pin Description
PIN NAME
FUNCTION
1
2
3
OUT Video Output
GND Ground
IN Video Input
V
CC
MAX4090
Power-Supply Voltage. Bypass with a 0.1µF
capacitor to ground as close to pin as
possible.
IN
4
V
CC
OUT
R
IN
R
L
CLAMP
Shutdown. Pull SHDN low to place the
5
6
SHDN
MAX4090 in low-power shutdown mode.
FB
Feedback. Connect to OUT.
FB
SHDN
GND
6
_______________________________________________________________________________________
3V/5V, 6dB Video Buffer with Sync-Tip Clamp
and 150nA Shutdown Current
The active sync-tip clamp also requires that the input
Detailed Description
impedance seen by the input capacitor be less than
The MAX4090 3V/5V, 6dB video buffer with sync-tip
100Ω typically to function properly. This is easily met
by the 75Ω input resistor prior to the input-coupling
capacitor and the back termination from a prior stage.
Insufficient input resistance to ground causes the
MAX4090 to appear to oscillate. Never operate the
MAX4090 in this mode.
clamp and low-power shutdown mode is available in tiny
SOT23 and SC70 packages. The MAX4090 is designed
to drive DC-coupled, 150Ω back-terminated video loads
in portable video applications such as digital still cams,
portable DVD players, digital camcorders, PDAs, video-
enabled cell phones, portable game systems, and note-
book computers. The input clamp positions the video
waveform at the output and allows the MAX4090 to be
used as a DC-coupled output driver.
Using the MAX4090 with the
Reconstruction Filter
In most video applications, the video signal generated
from the DAC requires a reconstruction filter to smooth
out the signal and attenuate the sampling aliases. The
MAX4090 is a direct DC-coupled output driver, which
can be used after the reconstruction filter to drive the
video signal. The driving load from the video DAC can
be varied from 75Ω to 300Ω. A low input impedance
(<100Ω) is required by the MAX4090 in normal opera-
tion, special care must be taken when a reconstruction
filter is used in front of the MAX4090.
The MAX4090 operates from a single 2.7V to 5.5V sup-
ply and consumes only 6.5mA of supply current. The
low-power shutdown mode reduces the supply current
to 150nA, making the MAX4090 ideal for low-voltage,
battery-powered video applications.
The input signal to the MAX4090 is AC-coupled
through a capacitor into an active sync-tip clamp cir-
cuit, which places the minimum of the video signal at
approximately 0.38V. The output buffer amplifies the
video signal while still maintaining the 0.38V clamp volt-
For standard video signal, the video passband is about
6MHz and the system oversampling frequency is at
27MHz. Normally, a 9MHz BW lowpass filter can be
used for the reconstruction filter. This section demon-
strates the methods to build simple 2nd- and 3rd-order
passive butterworth lowpass filters at the 9MHz cutoff
frequency and the techniques to use them with the
MAX4090 (Figures 1 and 4).
age at the output. For example, if V = 0.38V, then
IN
V
= 0.38V. If V = (0.38V + 1V) = 1.38V, then V
OUT
IN OUT
= (0.38V + 2 X (1V)) = 2.38V. The net result is that a 2V
video output signal swings within the usable output
voltage range of the output buffer when V
= 3V.
CC
Shutdown Mode
The MAX4090 features a low-power shutdown mode
(I
= 150nA) for battery-powered/portable applica-
2nd-Order Butterworth Lowpass Filter Realization
Table 1 shows the normalized 2nd-order butterworth
LPF component values at 1rad/s with a source/load
impedance of 1Ω.
SHDN
tions. Pulling the SHDN pin high enables the output.
Connecting the SHDN pin to ground (GND) disables
the output and places the MAX4090 into a low-power
shutdown mode.
With the following equations, the L and C can be calcu-
lated for the cutoff frequency at 9MHz. Table 2 shows
the appropriated L and C values for different source/
load impedance, the bench measurement values for
the -3dB BW and attenuation at 27MHz. There is
approximately 20dB attenuation at 27MHz, which effec-
tively attenuates the sampling aliases. The MAX4090
requires low input impedance for stable operation and
it does not like the reactive input impedance. For R1/R2
Applications Information
Input Coupling the MAX4090
The MAX4090 input must be AC-coupled because the
input capacitor stores the clamp voltage. The MAX4090
requires a typical value of 0.1µF for the input clamp to
meet the Line Droop specification. A minimum of a
ceramic capacitor with an X7R temperature coefficient
is recommended to avoid temperature-related prob-
lems with Line Droop. For extended temperature opera-
tion, such as outdoor applications, or where the
impressed voltage is close to the rated voltage of the
capacitor, a film dielectric is recommended. Increasing
the capacitor value slows the clamp capture time.
Values above 0.5µF should be avoided since they do
not improve the clamp’s performance.
greater than 100Ω, a series resistor R (Figure 1)
IS
Table 1. 2nd Order Butterworth Lowpass
Filter Normalized Values
Rn1 = Rn2 (Ω)
Cn1 (F)
Ln1 (H)
1
1.414
1.414
_______________________________________________________________________________________
7
3V/5V, 6dB Video Buffer with Sync-Tip Clamp
and 150nA Shutdown Current
between 20Ω to 100Ω is needed to isolate the input
capacitor (C4) to the filter to prevent the oscillation
problem.
3rd-Order Butterworth Lowpass Filter Realization
If more flat passband and more stopband attenuation
are needed, a 3rd-order LPF can be used. The design
procedures are similar to the 2nd-order butterworth
LPF.
C
L R
n L
2πf
C
n
C=
L=
Table 3 shows the normalized 3rd-order butterworth
lowpass filter with the cutoff frequency at 1 rad/s and
the stopband frequency at 3 rad/s. Table 4 shows the
appropriated L and C values for different source/load
impedance and the bench measurement values for
-3dB BW and attenuation at 27MHz. The attenuation is
over 40dB at 27MHz. At 6MHz, the attenuation is
approximately 0.6dB for R1 = R2 = 150Ω (Figure 5).
2πf R
C L
Figure 2 shows the frequency response for R1 = R2 =
150Ω. At 6MHz, the attenuation is about 1.4dB. The
attenuation at 27MHz is about 20dB. Figure 3 shows
the multiburst response for R1 = R2 = 150Ω.
V
CC
C7
1µF
2-POLE RECONSTRUCTION LPF
L1
4
R
C4
0.1µF
IS
R3
75Ω
V
CC
V
OUT
49.9Ω
3.9µH
VIDEO
CURRENT
DAC
3
5
1
6
IN
OUT
FB
C1
150pF
MAX4090
R1
150Ω
R2
150Ω
SHDN
GND
2
V
CC
Figure 1. 2nd-Order Butterworth LPF with MAX4090
FREQUENCY RESPONSE
0
-10
-20
-30
-40
-50
-60
V
IN
500mV/div
V
OUT
500mV/div
10µs/div
0.1
1
10
100
FREQUENCY (MHz)
Figure 2. Frequency Response
Figure 3. Multiburst Response
8
_______________________________________________________________________________________
3V/5V, 6dB Video Buffer with Sync-Tip Clamp
and 150nA Shutdown Current
V
CC
3-POLE RECONSTRUCTION LPF
C3
6.8pF
C7
1µF
4
R
C4
0.1µF
IS
L1
4.7µH
R3
75Ω
V
CC
49.9Ω
V
OUT
VIDEO
CURRENT
DAC
3
5
1
6
IN
OUT
FB
C1
120pF
C2
120pF
R1
150Ω
R2
150Ω
MAX4090
SHDN
GND
2
V
CC
Figure 4. 3rd-Order Butterworth LPF with MAX4090
Table 2. Bench Measurement Values
Table 3. 3rd-Order Butterworth Lowpass
Filter Normalized Values
3dB
BW
ATTENUATION
AT 27MHz
(dB)
R1 = R2
(Ω)
C1
(pf)
L1
(µH)
R
IS
(Ω)
Rn1 = Rn2
Cn1 (F)
Cn2 (F)
Cn3 (F)
Ln1 (H)
(MHz)
(Ω)
75
330
150
120
82
1.8
3.9
4.7
8.2
0
8.7
9.0
9.3
8.7
20
20
22
20
1
0.923
0.923
0.06
1.846
150
200
300
50
50
100
Table 4. Bench Measurement Values
ATTENUATION AT
27MHz (dB)
R1 = R2 (Ω)
C1 (pF)
C2 (pF)
C3 (pF)
L (µH)
R
(Ω)
3dB BW (MHz)
IS
75
220
120
56
220
120
56
15.0
6.8
2.2
4.7
0
9.3
8.9
9.0
43
50
45
150
300
50
3.3
10.0
100
Sag Correction
typically > 220µF. In sag configuration, the MAX4090
eliminates the need for large coupling capacitors, and
instead requires two 22µF capacitors (Figure 6) to
reach the same performance as the large capacitor.
Bench experiments show that increasing the output
coupling capacitor C5 beyond 47µF does not improve
the performance. If the supply voltage is less than 4.5V,
the sag correction is not recommended for the
MAX4090.
In a 5V application, the MAX4090 can use the sag con-
figuration if an AC-coupled output video signal is
required. Sag correction refers to the low-frequency
compensation for the highpass filter formed by the
150Ω load and the output capacitor. In video applica-
tions, the cutoff frequency must be low enough to pass
the vertical sync interval to avoid field tilt. This cutoff
frequency should be less than 5Hz, and the coupling
capacitor must be very large in normal configuration,
_______________________________________________________________________________________
9
3V/5V, 6dB Video Buffer with Sync-Tip Clamp
and 150nA Shutdown Current
Layout and Power-Supply Bypassing
FREQUENCY RESPONSE
The MAX4090 operates from single 2.7V to 5.5V sup-
ply. Bypass the supply with a 0.1µF capacitor as close
to the pin as possible. Maxim recommends using
microstrip and stripline techniques to obtain full band-
width. To ensure that the PC board does not degrade
the device’s performance, design it for a frequency
greater than 1GHz. Pay careful attention to inputs and
outputs to avoid large parasitic capacitance. Whether
or not you use a constant-impedance board, observe
the following design guidelines:
0
-10
-20
-30
-40
-50
-60
• Do not use wire-wrap boards; they are too inductive.
• Do not use IC sockets; they increase parasitic
capacitance and inductance.
0.1
1
10
100
FREQUENCY (MHz)
• Use surface-mount instead of through-hole compo-
nents for better, high-frequency performance.
Figure 5. Frequency Response for R1 = R2 = 150Ω
• Use a PC board with at least two layers; it should be
as free from voids as possible.
• Keep signal lines as short and as straight as possible.
Do not make 90° turns; round all corners.
V
CC
3-POLE RECONSTRUCTION LPF
C3
6.8pF
C7
1µF
4
C5
22µF
L1
4.7µH
R
C4
0.1µF
IS
R3
75Ω
V
CC
V
OUT
49.9Ω
VIDEO
3
5
1
6
IN
OUT
FB
CURRENT
DAC
C1
C2
120pF
R1
R2
150Ω
C6
22µF
MAX4090
120pF
150Ω
SHDN
GND
2
V
CC
Figure 6. Sag Correction Configuration
10 ______________________________________________________________________________________
3V/5V, 6dB Video Buffer with Sync-Tip Clamp
and 150nA Shutdown Current
V
CC
= 2.7V TO 5.5V
V
CC
C
BYP
0.1µF
SHDN
OUT
MAX4090
C
0.1µF
IN
R
SOURCE
75Ω
IN
R
75Ω
OUT
E
OUT
R
IN
E
SIGNAL
75Ω
R
75Ω
L
CLAMP
FB
GND
Figure 7. Typical Operating Circuit
Chip Information
TRANSISTOR COUNT: 755
PROCESS: BiCMOS
______________________________________________________________________________________ 11
3V/5V, 6dB Video Buffer with Sync-Tip Clamp
and 150nA Shutdown Current
Package Information (continued)
(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information
go to www.maxim-ic.com/packages.)
PACKAGE OUTLINE, SOT-23, 6L
1
21-0058
F
1
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.
12 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600
© 2004 Maxim Integrated Products
Printed USA
is a registered trademark of Maxim Integrated Products.
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