Datasheet

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LT1217

Low Power 10MHz

Current Feedback Amplifier

ESCRIPTIO

The LT1217 is a 10MHz current feedback amplifier with DC

characteristics better than many voltage feedback ampli-

fiers. This versatile amplifier is fast, 280ns settling to 0.1%

for a 10V step thanks to its 500V/µs slew rate. The LT1217

is manufactured on Linear Technology’s proprietary

complementary bipolar process resulting in a low 1mA

quiescent current. To reduce power dissipation further,

the LT1217 can be turned off, eliminating the load current

and dropping the supply current to 350µA.

The LT1217 is excellent for driving cables and other low

impedance loads thanks to a minimum output drive cur-

rent of 50mA. Operating on any supplies from ±5V to ±15V

allows the LT1217 to be used in almost any system. Like

other current feedback amplifiers, the LT1217 has high

gain bandwidth at high gains. The bandwidth is over 1MHz

at a gain of 100.

The LT1217 comes in the industry standard pinout and

can upgrade the performance of many older products.

■

1mA Quiescent Current

■

50mA Output Current (Minimum)

■

10MHz Bandwidth

■

500V/µs Slew Rate

■

280ns Settling Time to 0.1%

■

Wide Supply Range, ±5V to ±15V

■

1mV Input Offset Voltage

■

100nA Input Bias Current

■

100MΩ Input Resistance

■

Video Amplifiers

■

Buffers

■

IF and RF Amplification

■

Cable Drivers

■

8, 10, 12-Bit Data Acquisition Systems

ITY

Cable Driver Voltage Gain vs Frequency

FREQUENCY (Hz)

100k

–20

AMPLIFIER VOLTAGE GAIN (dB)

1M 10M 100M

LT1217 • TA02

–10

= 30Ω

= 100Ω

= 330Ω

= 1.3k

= ∞

= ±15V

= 3k

= 100Ω

OUT



75Ω

75Ω

CABLE

75Ω

LT1217

LT1217 • TA01

= 1 +



AT AMPLIFIER OUTPUT.

6dB LESS AT V

OUT

–

Summary of content (8 pages)

PAGE 1
LT1217 Low Power 10MHz Current Feedback Amplifier U DESCRIPTIO FEATURES ■ ■ ■ ■ ■ ■ ■ ■ ■ 1mA Quiescent Current 50mA Output Current (Minimum) 10MHz Bandwidth 500V/µs Slew Rate 280ns Settling Time to 0.1% Wide Supply Range, ±5V to ±15V 1mV Input Offset Voltage 100nA Input Bias Current 100MΩ Input Resistance The LT1217 is a 10MHz current feedback amplifier with DC characteristics better than many voltage feedback amplifiers. This versatile amplifier is fast, 280ns settling to 0.
PAGE 2
LT1217 U W W W Supply Voltage ...................................................... ±18V Input Current ...................................................... ±10mA Input Voltage ............................ Equal to Supply Voltage Output Short Circuit Duration (Note 1) ......... Continuous Operating Temperature Range ..................... 0°C to 70°C Storage Temperature Range ................. – 65°C to 150°C Junction Temperature...........................................
PAGE 3
LT1217 U W TYPICAL PERFOR A CE CHARACTERISTICS PHASE 45 4 180 3 225 2 1 VS = ±15V RL = 100Ω RF = 3k 0 –1 –2 0.01 –3dB BANDWIDTH (MHz) 135 PHASE SHIFT (DEGREES) GAIN 5 PEAKING ≤ 0.5dB PEAKING ≤ 5dB 25 90 6 RF = 1k 15 RF = 2k 10 RF = 3k 5 1.0 2 4 6 8 10 12 14 PHASE 45 180 18 225 17 16 15 VS = ±15V RL = 100Ω RF = 3k RF = 1k 8 RF = 2k 6 RF = 3k 4 RF = 1k RF = 2k 10 RF = 3k 8 6 RF = 5.
PAGE 4
LT1217 U W TYPICAL PERFOR A CE CHARACTERISTICS Maximum Capacitive Load vs Feedback Resistor Total Harmonic Distortion vs Frequency 1000 VS = ±5V VS = ±15V 100 VS = ±15V RL = 400Ω RF = RG = 3kΩ 0.01 VO = 7VRMS 2 3 5 4 6 8 7 9 1000 10000 Input Common Mode Limit vs Temperature OUTPUT SATURATION VOLTAGE (V) V+ COMMON MODE RANGE (V) –1.0 V+ = +5V TO +18V –3.0 3.0 V– = –5V TO –18V 1.0 V– –50 –25 0 25 50 75 100 –1.0 –1.5 RL = ∞ ±5V ≤ VS ≤ ±18V –2.0 2.0 1.5 1.0 0.
PAGE 5
LT1217 U W TYPICAL PERFOR A CE CHARACTERISTICS Settling Time to 10mV vs Output Step Settling Time to 1mV vs Output Step 10 VS = ±15V RF = RG = 3k 6 1.4 VS = ±15V RF = RG = 3k 8 6 INVERTING OUTPUT STEP (V) 4 2 NON-INVERTING 0 NON-INVERTING –2 T = 125°C 1.2 –4 –6 4 NON-INVERTING INVERTING 2 0 –2 NON-INVERTING –4 SUPPLY CURRENT (mA) 8 OUTPUT STEP (V) Supply Current vs Supply Voltage 10 1.0 T = 25°C 0.8 T = –55°C 0.6 T = –55°C T = 25°C, 125°C 0.
PAGE 6
LT1217 W U U UO APPLICATI S I FOR ATIO care to minimize the stray capacitance between the output and the inverting input. Capacitance on the inverting input to ground will cause peaking in the frequency response (and overshoot in the transient response), but it does not degrade the stability of the amplifier. The amount of capacitance that is necessary to cause peaking is a function of the closed loop gain taken. The higher the gain, the more capacitance is required to cause peaking.
PAGE 7
LT1217 U W U UO APPLICATI S I FOR ATIO Large Signal Response, AV = 2, R F = RG = 3k, Slew Rate 500V/µs Offset Adjust Output offset voltage is equal to the input offset voltage times the gain plus the inverting input bias current times the feedback resistor. The LT1217 output offset voltage can be nulled by pulling approximately 30µA from pin 1 or 5. The easy way to do this is to use a 100kΩ pot between pin 1 and 5 with a 430kΩ resistor from the wiper to ground for 15V supply applications.
PAGE 8
LT1217 W W SI PLIFIED SCHE ATIC 7 90k 1 5 BIAS 60k 8 3 6 2 BIAS 4 LT1217 • TA08 U PACKAGE DESCRIPTIO 0.300 – 0.320 (7.620 – 8.128) N8 Package 8-Lead Plastic DIP TJ MAX θJA 150°C 100°C/W Dimensions in inches (millimeters) unless otherwise noted. 0.065 (1.651) TYP 0.045 – 0.065 (1.143 – 1.651) 0.130 ± 0.005 (3.302 ± 0.127) 8 0.009 - 0.015 (0.229 - 0.381) +0.025 0.325 –0.015 +0.635 8.255 –0.381 ( 0.125 (3.175) MIN 0.045 ± 0.015 (1.143 ± 0.381) ) 0.400 (10.160) MAX 0.100 ± 0.010 (2.