MAX9504AEUT+T Maxim Integrated Products, MAX9504AEUT+T Datasheet - Page 10

• Manufacturer Part Number: MAX9504AEUT+T
• Description: IC AMP VIDEO HI CUR SOT23-6
• Manufacturer: Maxim Integrated Products

Specifications of MAX9504AEUT+T

• Applications: General Purpose
• Number Of Circuits: 1
• -3db Bandwidth: 47MHz
• Slew Rate: 165 V/µs
• Current - Supply: 5mA
• Current - Output / Channel: 110mA
• Voltage - Supply, Single/dual (±): 2.7 V ~ 5.5 V
• Mounting Type: Surface Mount
• Package / Case: SOT-23-6
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

If a flatter passband and more stopband attenuation
are desired, a 3rd-order lowpass filter can be used.
The design procedures are similar to the 2nd-order
Butterworth lowpass filter.
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
appropriate L and C values for different source/load
impedances, the bench measurement values for the -3dB
frequency and the attenuation at 27MHz. The attenua-
tion is over 40dB at 27MHz. At 6MHz, the attenuation is
approximately 0.6dB for R1 = R2 = 150Ω (Figure 6).
Table 3. 3rd-Order Butterworth Lowpass
Filter Normalized Values
Table 4. Bench Measurement Values—3rd Order LPF
3V/5V, 6dB Video Amplifiers with
High Output-Current Capability
Figure 5. Multiburst Response
10
Rn1 = Rn2
R1 = R2 (Ω)
3rd-Order Butterworth Lowpass Filter Realization
(Ω)
150
300
______________________________________________________________________________________
1
75
Cn1 (F)
0.923
C1 (pF)
220
120
56
10µs/div
Cn2 (F)
0.923
C2 (pF)
220
120
56
Cn3 (F)
0.06
C3 (pF)
15.0
6.8
3.3
V
500mV/div
V
1V/div
IN
OUT
Ln1 (H)
1.846
L (µH)
10.0
2.2
4.7
The Y/C-to-composite mixer and driver use two low-
pass filters, the MAX9504A and the MAX9504B. In
Figure 7, the top video DAC generates a luma signal,
which is filtered through the passive RLC network and
then amplified by the MAX9504B. The bottom video
DAC generates a chroma signal, which is filtered and
then amplified by the MAX9504A.
LUMA OUT is directly connected to the output of the
MAX9504B through a 75Ω back-termination resistor;
likewise, CHROMA OUT to the output of the MAX9504A.
CVBS OUT (the composite video with blanking and
sync output) is created by AC-coupling the chroma sig-
nal to the luma signal through the 470pF capacitor,
which looks like an AC short at the color subcarrier fre-
quency of 3.58MHz for NTSC or 4.43MHz for PAL.
This circuit relies upon the feature that the MAX9504A/
MAX9504B can drive two loads at the same time.
Figure 6. Frequency Response for 3rd-Order Lowpass Filter
Y/C-to-Composite Mixer and Driver Circuit
3dB FREQUENCY (MHz)
-10
-20
-30
-40
-50
-60
0
9.3
8.9
9.0
0.1
FREQUENCY RESPONSE
FREQUENCY (MHz)
1
ATTENUATION AT 27MHz (dB)
10
43
50
45
100