LT6210/LT6211
TYPICAL APPLICATIO S
Line Driver with Power Saving Mode
In applications where low distortion or high slew rate are
desirable but not necessary at all times, it may be possible
to decrease the LT6210 or LT6211’s quiescent current
when the higher power performance is not required.
Figure 5 illustrates a method of setting quiescent current
with a FET switch. In the 5V dual supply case pictured,
shorting the ISET pin through an effective 20k to ground
sets the supply current to 6mA, while the 240k resistor at
the ISET pin with the FET turned off sets the supply current
to approximately 1mA. The feedback resistor of 4.02k is
selected to minimize peaking in low power mode. The
R3
4.02k
5V
VIN
HS/LP
4–
6
1
LT6210
3+
2
5
–5V
R2 R1
22k 240k
2N7002
6210 F05
VOUT
RLOAD
150Ω
Figure 5. Line Driver with Low Power Mode
bandwidth of the LT6210 in this circuit increases from
about 40MHz in low power mode to over 200MHz in full
speed mode, as illustrated in Figure 6. Other AC specs also
improve significantly at the higher current setting. The
following table shows harmonic distortion at 1MHz with a
2VP-P sinusoid at the two selected current levels.
Harmonic Distortion
LOW POWER
HD2
–53dBc
HD3
–46dBc
FULL SPEED
HD2
–68dBc
HD3
–77dBc
3
2
1
FULL
SPEED
0
MODE
IS = 6mA
–1
LOW POWER
–2
MODE
IS = 1mA
–3
–4
–5 TA = 25°C
VOUT = 100mVP-P
–6
0
1
10
100
FREQUENCY (MHz)
1000
6210 F06
Figure 6. Frequency Response for Full
Speed and Low Power Mode
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PART NUMBER
DESCRIPTION
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LT1795
LT1806/LT1807
50MHz, 500mA Programmable IS Amplifier
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COMMENTS
Single, Dual and Quad Current Feedback Amplifiers
Single, Dual and Quad Current Feedback Amplifiers
Dual and Triple Current Feedback Amplifiers
Dual Current Feedback Amplifier
Single and Dual Voltage Feedback Amplifiers
Single, Dual and Quad Voltage Feedback Amplifiers
16 Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900 q FAX: (408) 434-0507 q www.linear.com
62101f
LT/TP 0204 1K • PRINTED IN USA
© LINEAR TECHNOLOGY CORPORATION 2003