LMH6624MF Datasheet, PDF (19/31 Pages) Texas Instruments – LMH6624/LMH6626 Single/Dual Ultra Low Noise Wideband Operational Amplifier

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LMH6624
SNOSA42F – NOVEMBER 2002 – REVISED MARCH 2013
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LOW NOISE INTEGRATOR
The LMH6624/LMH6626 implement a deBoo integrator shown in Figure 58. Positive feedback maintains
integration linearity. The LMH6624/LMH6626’s low input offset voltage and matched inputs allow bias current
cancellation and provide for very precise integration. Keeping R_G and R_S low helps maintain dynamic stability.
K_O
V_O # V_IN
sR_SC
R_F
; K_O = 1 +
R_G
R_B
R_S
V_IN
C
+
R
-
R_F
V_O
50:
50:
R_F = R_B
R_G
R_G = R_S||R
Figure 58. Low Noise Integrator
HIGH-GAIN SALLEN-KEY ACTIVE FILTERS
The LMH6624/LMH6626 are well suited for high gain Sallen-Key type of active filters. Figure 59 shows the 2^nd
order Sallen-Key low pass filter topology. Using component predistortion methods discussed in OA-21
(SNOA369) enables the proper selection of components for these high-frequency filters.
C₁
R₁
R₂
C₂
+
-
R_F
R_G
Figure 59. Sallen-Key Active Filter Topology
LOW NOISE MAGNETIC MEDIA EQUALIZER
The LMH6624/LMH6626 implement a high-performance low noise equalizer for such application as magnetic
tape channels as shown in Figure 60. The circuit combines an integrator with a bandpass filter to produce the
low noise equalization. The circuit’s simulated frequency response is illustrated in Figure 61.
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