Datasheet

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LT1010

1010fe

APPLICATIONS

Boost Op Amp Output

Isolate Capacitive Loads

Drive Long Cables

Audio Ampliﬁers

Video Ampliﬁers

Power Small Motors

Operational Power Supply

FET Driver

TYPICAL APPLICATION

DESCRIPTION

Fast ±150mA Power Buffer

The LT

1010 is a fast, unity-gain buffer that can increase

the output capability of existing IC op amps by more than

an order of magnitude. This easy-to-use part makes fast

ampliﬁers less sensitive to capacitive loading and reduces

thermal feedback in precision DC ampliﬁers.

Designed to be incorporated within the feedback loop, the

buffer can isolate almost any reactive load. Speed can be

improved with a single external resistor. Internal operating

currents are essentially unaffected by the supply voltage

range. Single supply operation is also practical.

This monolithic IC is supplied in 8-pin miniDIP, plastic

TO-220 and 8-pin DFN packages. The low thermal re-

sistance power package is an aid in reducing operating

junction temperatures.

Very Low Distortion Buffered Preampliﬁer

L, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.

All other trademarks are the property of their respective owners.

FTEATURES

20MHz Bandwidth

75V/µs Slew Rate

Drives ±10V Into 75Ω

5mA Quiescent Current

Drives Capacitive Loads > 1µF

Current and Thermal Limit

Operates from Single Supply ≥ 4.5V

Very Low Distortion Operation

Available in 8-Pin miniDIP, Plastic TO-220

and Tiny 3mm × 3mm × 0.75mm 8-Pin DFN Packages

–

LT1056CN8 LT1010CT

IN OUT

OUTPUT

BOOST

1010 TA01

LM334

SET

= 2mA

SET

33.2Ω

NOTE 1: ALL RESISTORS 1% METAL FILM

NOTE 2: SUPPLIES WELL BYPASSED AND LOW Z

–

50Ω

22pF

18V

–18V

100Ω

10k

FREQUENCY (Hz)

0.1

HARMONIC DISTORTION (%)

0.2

0.4

10 1k 10k 100k

1010 TA02

100

0.3

OUT

= 10V

P-P

= 400Ω

Summary of content (20 pages)

PAGE 1
LT1010 Fast ±150mA Power Buffer FTEATURES n n n n n n n n n DESCRIPTION 20MHz Bandwidth 75V/µs Slew Rate Drives ±10V Into 75Ω 5mA Quiescent Current Drives Capacitive Loads > 1µF Current and Thermal Limit Operates from Single Supply ≥ 4.5V Very Low Distortion Operation Available in 8-Pin miniDIP, Plastic TO-220 and Tiny 3mm × 3mm × 0.75mm 8-Pin DFN Packages n n n n n n n Designed to be incorporated within the feedback loop, the buffer can isolate almost any reactive load.
PAGE 2
LT1010 ABSOLUTE MAXIMUM RATINGS PRECONDITIONING (Note 1) Total Supply Voltage ..............................................±22V Continuous Output Current (Note 2).................. ±150mA Input Current (Note 3).......................................... ±40mA Junction Temperature Range LT1010C................................................. 0°C to 125°C Storage Temperature Range.................... –65°C to 150°C Lead Temperature (Soldering, 10 sec)...................
PAGE 3
LT1010 ELECTRICAL CHARACTERISTICS The l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. (See Note 4. Typical values in curves.) SYMBOL PARAMETER CONDITIONS (Note 4) VOS Output Offset Voltage (Note 4) MIN MAX UNITS 0 –20 150 220 mV mV VS = ±15V, VIN = 0V 20 100 mV IOUT = 0mA IOUT ≤ 150mA l 0 0 0 250 500 800 µA µA µA l 0.995 1.
PAGE 4
LT1010 TYPICAL PERFORMANCE CHARACTERISTICS Bandwidth Phase Lag 50 RL = 50Ω 30 20 VIN = 100mVP-P CL 100pF AV = –3dB TJ = 25°C 10 0 30 20 10 QUIESCENT CURRENT (mA) 20 RL = 50Ω RL = 200Ω 10 5 40 CL = 100pF RS = 50Ω IBIAS = 0 TJ = 25°C 10 5 FREQUENCY (MHz) 2 Small-Step Response 50 OUTPUT 0 –50 RL = 200Ω 10 5 20 CL = 100pF RS = 50Ω RBIAS = 20Ω TJ = 25°C 10 5 FREQUENCY (MHz) 2 20 1010 G03 Capacitive Loading 10 IBIAS = 0 TJ = 25°C VOLTAGE GAIN (dB) RL = 100Ω TJ = 25°C INPUT RL = 50Ω O
PAGE 5
LT1010 TYPICAL PERFORMANCE CHARACTERISTICS Output Offset Voltage Input Bias Current 200 150 V+ = 38V – = –2V V 100 V+ = 2V V– = –38V 50 0 –50 0 50 100 TEMPERATURE (°C) VIN = 0 150 V+ = 38V V– = –2V 100 V+ = 2V V– = –38V 50 0 –50 150 Input Bias Current 200 0 50 100 TEMPERATURE (°C) 1010 G10 VS = ±15V RL = 75Ω 150 TJ = 125°C TJ = 25°C 100 TJ = –55°C 50 0 –150 150 Output Noise Voltage 200 IOUT ≤ 150mA VS = 4.5V 0.998 NOISE VOLTAGE (nV/√Hz) OUTPUT RESISTANCE (Ω) GAIN (V/V) 0.
PAGE 6
LT1010 TYPICAL PERFORMANCE CHARACTERISTICS Total Harmonic Distortion 0.4 VS = ±20V 0.8 HARMONIC DISTORTION (%) RBIAS = 100Ω RBIAS = 20Ω 0.7 0.6 0.5 –50 0 100 50 TEMPERATURE (°C) RL = 50Ω f = 10kHz VS = ±15V TC = 25°C 0.3 0.2 IBIAS = 0 0.1 0 0.1 150 RBIAS = 50Ω 1 10 OUTPUT VOLTAGE (VP-P) Shorted Input Characteristics PEAK POWER (W) INUPT CURRENT (mA) 0 –25 5 0 INPUT VOLTAGE (V) 10 15 1010 G22 RL = 100Ω 1 10 100 FREQUENCY (kHz) 1000 Peak Output Current 0.
PAGE 7
LT1010 APPLICATIONS INFORMATION General These notes briefly describe the LT1010 and how it is used; a detailed explanation is given elsewhere.1 Emphasis here will be on practical suggestions that have resulted from working extensively with the part over a wide range of conditions. A number of applications are also outlined that demonstrate the usefulness of the buffer beyond that of driving a heavy load. idealized buffer with the unloaded gain specified for the LT1010.
PAGE 8
LT1010 APPLICATIONS INFORMATION a ground plane is prudent, especially when operating at high frequencies. The buffer slew rate can be reduced by inadequate supply bypass. With output current changes much above 100mA/µs, using 10µF solid tantalum capacitors on both supplies is good practice, although bypassing from the positive to the negative supply may suffice. Normally, thermal overload protection will limit dissipation and prevent damage.
PAGE 9
LT1010 APPLICATIONS INFORMATION The offset voltage specified for VS = ±15V, VIN = 0V and TA = 25°C will suffice for a worst-case condition. V+ IS VIN Stability depends upon the RFCF time constant or the closed-loop bandwidth. With an 80kHz bandwidth, ringing is negligible for CL = 0.068µF and damps rapidly for CL = 0.33µF. The pulse response is shown in the graph. IS A1 LT1010 At lower frequencies, the buffer is within the feedback loop so that its offset voltage and gain errors are negligible.
PAGE 10
LT1010 APPLICATIONS INFORMATION This is a good example of how fast op amps can be made quite easy to use by employing an output buffer. Integrator A lowpass amplifier can be formed just by using large CF in the inverter described earlier, as long as the increasing closed-loop output impedance above the cutoff frequency is not a problem and the op amp is capable of supplying the required current at the summing junction. stage. Feedback is arranged in the conventional manner, although the 68µF-0.
PAGE 11
LT1010 APPLICATIONS INFORMATION current boost. The appearance is always worse with fast rise signal generators than in practical applications. R3 800Ω C1 20pF – INPUT + R1 50Ω Track and Hold R4 39Ω A2 LT1010 A1 HA2625 R2 200Ω OUTPUT 1 R5 39Ω A3 LT1010 The 5MHz track and hold shown here has a 400kHz power bandwidth driving ±10V. A buffered input follower drives the hold capacitor, C4, through Q1, a low resistance FET switch.
PAGE 12
LT1010 APPLICATIONS INFORMATION R2 100k 0.01% – A1 LT1012 V2 R4 10Ω 0.1% A2 LT1010 + R3 100k 0.01% IOUT = R2(V2 – V1) R1R4 IOUT R4 100k 0.01% A2 LT1010 IOUT = – 6 A1 LM163 ×10 5 R4 2k 0.1% OUTPUT R5 2k 0.1% A3 LT118A C2 10pF D2 1N457 R7 99.8k 0.1% VV 1V/V R6 99.8k 0.1% VI 10mA/V 1010 AI15 This circuit uses an instrumentation amplifier to eliminate the matched resistors. The input is not high impedance and must be driven from a low impedance source like an op amp.
PAGE 13
LT1010 APPLICATIONS INFORMATION High Current Booster 5V 15pF 10k 15V 68pF 10k INPUT 22µF + 0.18Ω 1k Q3 2N3906 33Ω Q1 MJE2955 – LT1056 LT1010 + OUTPUT 100Ω 100Ω Q2 MJE3055 Q4 2N3904 33Ω –15V 1010 AI17 + HEAT SINK OUTPUT TRANSISTORS 1k 22µF 0.18Ω Wideband FET Input Stabilized Buffer The figure below shows a highly stable unity-gain buffer with good speed and high input impedance. Q1 and Q2 constitute a simple, high speed FET input buffer.
PAGE 14
LT1010 APPLICATIONS INFORMATION Figures A and B show response with both output stages. The LT1010 is used in Figure A (Trace A = input, Trace B = output). Figure B uses the discrete stage and is slightly faster. Either stage provides more than adequate performance for driving video cable or data converters and the LT1012 maintains DC stability under all conditions.
PAGE 15
LT1010 APPLICATIONS INFORMATION Typical thermal calculations for the miniDIP package are detailed in the following paragraphs. For 4.8mA supply current (typical at 50°C, 30V supply voltage—see supply current graphs) to the LT1010 at ±15V, PD = power dissipated in the part is equal to: (30V)(0.0048A) = 0.144W The rise in junction is then: (0.144W)(100°C/W—This is θJA for the N package) = 14.4°C. This means that the junction temperature in 50°C ambient air without driving any current into a load is: 14.
PAGE 16
LT1010 SCHEMATIC DIAGRAM (Excluding protection circuits) R6 15Ω Q11 R5 1.5k V+ R10 200Ω R7 300Ω Q18 BIAS Q17 R2 1k Q5 R3 1k Q6 Q7 R4 1k Q21 Q12 R8 1k Q2 Q15 Q4 Q1 R1 4k R11 200Ω C1 30pF Q8 Q3 Q13 Q9 Q19 Q10 Q14 R13 200Ω Q20 R12 3k R14 7Ω OUTPUT Q22 R9 Q16 4k INPUT 1010 SD V– DEFINITION OF TERMS Output Offset Voltage: The output voltage measured with the input grounded (split supply operation). Input Bias Current: The current out of the input terminal.
PAGE 17
LT1010 PACKAGE DESCRIPTION DD Package 8-Lead Plastic DFN (3mm × 3mm) (Reference LTC DWG # 05-08-1698 Rev C) 0.70 ±0.05 3.5 ±0.05 1.65 ±0.05 2.10 ±0.05 (2 SIDES) PACKAGE OUTLINE 0.25 ± 0.05 0.50 BSC 2.38 ±0.05 RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS APPLY SOLDER MASK TO AREAS THAT ARE NOT SOLDERED PIN 1 TOP MARK (NOTE 6) 0.200 REF 3.00 ±0.10 (4 SIDES) R = 0.125 TYP 5 0.40 ± 0.10 8 1.65 ± 0.10 (2 SIDES) 0.75 ±0.05 4 0.25 ± 0.05 1 (DD8) DFN 0509 REV C 0.50 BSC 2.38 ±0.10 0.00 – 0.
PAGE 18
LT1010 PACKAGE DESCRIPTION N8 Package 8-Lead PDIP (Narrow .300 Inch) (Reference LTC DWG # 05-08-1510) .300 – .325 (7.620 – 8.255) .008 – .015 (0.203 – 0.381) ( +.035 .325 –.015 8.255 +0.889 –0.381 ) .400* (10.160) MAX .130 ± .005 (3.302 ± 0.127) .045 – .065 (1.143 – 1.651) .065 (1.651) TYP 8 7 6 5 1 2 3 4 .255 ± .015* (6.477 ± 0.381) .120 (3.048) .020 MIN (0.508) MIN .018 ± .003 .100 (2.54) BSC N8 1002 (0.457 ± 0.076) NOTE: 1.
PAGE 19
LT1010 REVISION HISTORY (Revision history begins at Rev E) REV DATE DESCRIPTION PAGE NUMBER E 5/11 Revised temperature ranges and values in Absolute Maximum Ratings and Pin Configuration sections Revised Notes 2 and 4 in Electrical Characteristics section Updated temperature values in Power Dissipation, Thermal Considerations for the MiniDIP Package, and Thermal Resistance of DFN Package sections of the Applications Information section 2 3 8, 15 1010fe Information furnished by Linear Technology C
PAGE 20
LT1010 RELATED PARTS PART NUMBER DESCRIPTION COMMENTS LT1206 250mA, 60MHz Current Feedback Amplifier 900V/µs, Excellent Video Characteristics LT1210 1.1A, 35MHz Current Feedback Amplifier 900V/µs Slew Rate, Stable with Large Capacitive Loads LT1795 Dual 500mA, 50MHz CFA 500mA IOUT ADSL Driver LT1886 Dual 700MHz, 200mA Op Amp DSL Driver 1010fe 20 Linear Technology Corporation LT 0511 REV E • PRINTED IN USA 1630 McCarthy Blvd.