THS3001 Datasheet, PDF (24/32 Pages) Texas Instruments – 420-MHz HIGH-SPEED CURRENT-FEEDBACK AMPLIFIERS

THS3001, THS3002
420-MHz HIGH-SPEED CURRENT-FEEDBACK AMPLIFIERS
SLOS217A – JULY 1998 – REVISED JUNE 1999
APPLICATION INFORMATION
PCB design considerations (continued)
OUTPUT AMPLITUDE
vs
FREQUENCY
7
1 kΩ
6
CI = 1 pF
Cin
5
Vin
–
Vout
4
+
RL =
50 Ω 150 Ω
3
2
1
0
–1
–2 _{Gain = 1}
–3
VCC = ±15 V
VO = 200 mV RMS
CI = 0 pF
(Stray C Only)
–4
100k
1M
10M
100M
1G
f – Frequency – Hz
Figure 54
OUTPUT AMPLITUDE
vs
FREQUENCY
1
CI = 10 pF
0
–1
CI = Stray C Only
–2
Vin
–3
Cin
1 kΩ
50 Ω
–4
–5
1 kΩ
–
Vout
+
RL =
150 Ω
–6
Gain = –1
–7 VCC = ±15 V
VO = 200 mV RMS
–8
100k
1M
10M
100M
1G
f – Frequency – Hz
Figure 55
D Proper power-supply decoupling – Use a minimum 6.8-µF tantalum capacitor in parallel with a 0.1-µF
ceramic capacitor on each supply terminal. It may be possible to share the tantalum among several
amplifiers depending on the application, but a 0.1-µF ceramic capacitor should always be used on the
supply terminal of every amplifier. In addition, the 0.1-µF capacitor should be placed as close as possible
to the supply terminal. As this distance increases, the inductance in the connecting etch makes the capacitor
less effective. The designer should strive for distances of less than 0.1 inches between the device power
terminal and the ceramic capacitors.
thermal information
The THS300x incorporates output-current-limiting protection. Should the output become shorted to ground, the
output current is automatically limited to the value given in the data sheet. While this protects the output against
excessive current, the device internal power dissipation increases due to the high current and large voltage drop
across the output transistors. Continuous output shorts are not recommended and could damage the device.
Additionally, connection of the amplifier output to one of the supply rails (±V_CC) is not recommended. Failure
of the device is possible under this condition and should be avoided. But, the THS300x does not incorporate
thermal-shutdown protection. Because of this, special attention must be paid to the device’s power dissipation
or failure may result.
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