Datasheet
Table Of Contents
- FEATURES
- APPLICATIONS
- DESCRIPTION
- ABSOLUTE MAXIMUM RATINGS
- OPERATING RATINGS
- 5V ELECTRICAL CHARACTERISTICS
- 3.3V ELECTRICAL CHARACTERISTICS
- 2.7V ELECTRICAL CHARACTERISTICS
- CONNECTION DIAGRAM
- TYPICAL PERFORMANCE CHARACTERISTICS
- APPLICATION INFORMATION
- OPTIMIZING PERFORMANCE
- SHUTDOWN CAPABILITY AND TURN ON/ OFF BEHAVIOR
- OVERLOAD RECOVERY AND SWING CLOSE TO RAILS
- SINGLE SUPPLY VIDEO APPLICATION
- DC COUPLED, SINGLE SUPPLY BASEBAND VIDEO AMPLIFIER/DRIVER
- AC COUPLED VIDEO
- SAG COMPENSATION
- HOW TO PICK THE RIGHT VIDEO AMPLIFIER
- CURRENT TO VOLTAGE CONVERSION (TRANSIMPEDANCE AMPLIFIER (TIA))
- TRANSIMPEDANCE AMPLIFIER NOISE CONSIDERATIONS
- OTHER APPLICATIONS
- CAPACITIVE LOAD
- EVALUATION BOARD
- Revision History
2V
p-p
2V
p-p
2V
p-p
(A)
50% DUTY CYCLE
NO CLIPPING
(B)
LOW DUTY CYCLE
CLIPPED POSITIVE
(C)
HIGH DUTY CYCLE
CLIPPED NEGATIVE
4.0V (+) CLIPPING
2.5V
1.0V (-) CLIPPING
4.0V (+) CLIPPING
2.5V
1.0V (-) CLIPPING
4.0V (+) CLIPPING
2.5V
1.0V (-) CLIPPING
LMH6601, LMH6601-Q1
www.ti.com
SNOSAK9E –JUNE 2006–REVISED MARCH 2013
Figure 58. Headroom Considerations with AC Coupled Amplifiers
If a stage has a 3 V
PP
unclipped swing capability available at a given node, as shown in Figure 58, the maximum
allowable amplitude for an arbitrary waveform is ½ of 3V or 1.5 V
PP
. This is due to the shift in the average value
of the waveform as the duty cycle varies. Figure 58 shows what would happen if a 2 V
PP
signal were applied. A
low duty cycle waveform, such as the one in Figure 58B, would have high positive excursions. At low enough
duty cycles, the waveform could get clipped on the top, as shown, or a more subtle loss of linearity could occur
prior to full-blown clipping. The converse of this occurs with high duty cycle waveforms and negative clipping, as
depicted in Figure 58C.
HOW TO PICK THE RIGHT VIDEO AMPLIFIER
Apart from output current drive and voltage swing, the op amp used for a video amplifier/cable driver should also
possess the minimum requirement for speed and slew rate. For video type loads, it is best to consider Large
Signal Bandwidth (or LSBW in the Texas Instruments data sheet tables) as video signals could be as large as 2
V
PP
when applied to the commonly used gain of +2 configuration. Because of this relatively large swing, the op
amp Slew Rate (SR) limitation should also be considered. Table 2 shows these requirements for various video
line rates calculated using a rudimentary technique and intended as a first order estimate only.
Table 2. Rise Time, −3 dB BW, and Slew Rate Requirements for Various Video Line Rates
Video Line Rate Refresh Rate Horizontal Vertical Pixel Time Rise Time LSBW SR
Standard (HxV) (Hz) Active Active (KV%) (ns) (ns) (MHz) (V/μs)
(KH%)
TV_NTSC 451x483 30 84 92 118.3 39.4 9 41
VGA 640x480 75 80 95 33.0 11.0 32 146
SVGA 800x600 75 76 96 20.3 6.8 52 237
XGA 1024x768 75 77 95 12.4 4.1 85 387
SXGA 1280x1024 75 75 96 7.3 2.4 143 655
UXGA 1600x1200 75 74 96 4.9 1.6 213 973
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