LMH6552 Datasheet, PDF (20/38 Pages) Texas Instruments – 1.5-GHz Fully Differential Amplifier

LMH6552
SNOSAX9I – APRIL 2007 – REVISED JANUARY 2015
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357:
100:
50: ^{TWISTED PAIR}
RS = 50:
V_S
a ^61.8:
169:
+
V_CM
-
169:
27.6:
2 V_PP
50:
357:
A_V = 2 V/V
ENABLE
Figure 42. Fully Differential Cable Driver
9.2.1.3 Application Curves
Many application circuits will have capacitive loading. As shown in Figure 43 amplifier bandwidth is reduced with
increasing capacitive load, so parasitic capacitance should be strictly limited.
In order to ensure stability resistance should be added between the capacitive load and the amplifier output pins.
The value of the resistor is dependent on the amount of capacitive load as shown in Figure 44. This resistive
value is a suggestion. System testing will be required to determine the optimal value. Using a smaller resistor will
retain more system bandwidth at the expense of overshoot and ringing, while larger values of resistance will
reduce overshoot but will also reduce system bandwidth.
1
0
-1
C_L = 82 pF, R_O = 16:
-2
C_L = 39 pF, R_O = 21:
-3
C_L = 15 pF, R_O = 24:
-4
C_L = 5.6 pF, R_O = 23:
-5
-6 V_OD = 200 mV_PP
-7 ^AV ^{= 1}
LOAD = (CL || 1 k:) IN
-8 _{SERIES WITH 2 ROUTS}
-9
1
10
100
FREQUENCY (MHz)
1000
Figure 43. Frequency Response vs Capacitive Load
30
20
10
V⁺ = +5V
V^- = -5V
LOAD = 1 k: || CAP LOAD
0
1
10
100
CAPACITIVE LOAD (pF)
Figure 44. Suggested R_OUT vs Capacitive Load
20
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