Datasheet

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LT1818/LT1819

18189fb

TYPICAL APPLICATION

DESCRIPTION

400MHz, 2500V/µs, 9mA

Single/Dual Operational

Ampliﬁ ers

The LT

1818/LT1819 are single/dual wide bandwidth, high

slew rate, low noise and distortion operational ampliﬁ ers

with excellent DC performance. The LT1818/LT1819 have

been designed for wider bandwidth and slew rate, much

lower input offset voltage and lower noise and distortion

than devices with comparable supply current. The circuit

topology is a voltage feedback ampliﬁ er with the excellent

slewing characteristics of a current feedback ampliﬁ er.

The output drives a 100Ω load to ±3.8V with ±5V sup-

plies. On a single 5V supply, the output swings from 1V

to 4V with a 100Ω load connected to 2.5V. The ampliﬁ er

is unity-gain stable with a 20pF capacitive load without the

need for a series resistor. Harmonic distortion is –85dBc

up to 5MHz for a 2V

P-P

output at a gain of 2.

The LT1818/LT1819 are manufactured on Linear Tech-

nology’s advanced low voltage complementary bipolar

process. The LT1818 (single op amp) is available in

TSOT-23 and SO-8 packages; the LT1819 (dual op amp)

is available in MSOP-8 and SO-8 packages.

Single Supply Unity-Gain ADC Driver for Oversampling Applications

L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear

Technology Corporation. ThinSOT is a trademark of Linear Technology Corporation.

All other trademarks are the property of their respective owners.

FEATURES

APPLICATIONS

400MHz Gain Bandwidth Product

2500V/μs Slew Rate

–85dBc Distortion at 5MHz

9mA Supply Current Per Ampliﬁ er

6nV/√Hz Input Noise Voltage

Unity-Gain Stable

1.5mV Maximum Input Offset Voltage

8μA Maximum Input Bias Current

800nA Maximum Input Offset Current

40mA Minimum Output Current, V

OUT

= ±3V

±3.5V Minimum Input CMR, V

= ±5V

Speciﬁ ed at ±5V, Single 5V Supplies

Operating Temperature Range: –40°C to 85°C

Low Proﬁ le (1mm) TSOT-23 (ThinSOT™) Package

Wideband Ampliﬁ ers

Buffers

Active Filters

Video and RF Ampliﬁ cation

Communication Receivers

Cable Drivers

Data Acquisition Systems

FFT of Single Supply ADC Driver

FREQUENCY (Hz)

AMPLITUDE (dBc)

–10

–20

–30

–40

–50

–60

–70

–80

–90

–100

–110

18189 TA02

5M 10M 15M 20M 25M

= 5.102539MHz

= 50Msps

= 300mV

P-P

SFDR = 78dB

8192 POINT FFT

NO WINDOWING

OR AVERAGING

2 3

–

LT1818

2.5VDC

±1VAC

18189 TA01

18pF

2.5V

51.1Ω

LTC1744

14 BITS

50Msps

(SET FOR 2V

P-P

FULL SCALE)

–

Summary of content (18 pages)

PAGE 1
LT1818/LT1819 400MHz, 2500V/µs, 9mA Single/Dual Operational Amplifiers DESCRIPTION FEATURES n n n n n n n n n n n n n n 400MHz Gain Bandwidth Product 2500V/μs Slew Rate –85dBc Distortion at 5MHz 9mA Supply Current Per Ampliﬁer 6nV/√Hz Input Noise Voltage Unity-Gain Stable 1.5mV Maximum Input Offset Voltage 8μA Maximum Input Bias Current 800nA Maximum Input Offset Current 40mA Minimum Output Current, VOUT = ±3V ±3.
PAGE 2
LT1818/LT1819 ABSOLUTE MAXIMUM RATINGS (Note 1) Total Supply Voltage (V+ to V–) ..............................12.6V Differential Input Voltage (Transient Only, Note 2).....±6V Output Short-Circuit Duration (Note 3) ............ Indeﬁnite Operating Temperature Range (Note 8).... –40°C to 85°C Speciﬁed Temperature Range (Note 9) .... –40°C to 85°C Maximum Junction Temperature........................... 150°C Storage Temperature Range................... –65°C to 150°C Lead Temperature (Soldering, 10 sec) ....
PAGE 3
LT1818/LT1819 ELECTRICAL CHARACTERISTICS The l denotes the speciﬁcations which apply over the full operating temperature range, otherwise speciﬁcations are at TA = 25°C. (Note 9) VS = ±5V, VCM = 0V, unless otherwise noted.
PAGE 4
LT1818/LT1819 ELECTRICAL CHARACTERISTICS The l denotes the speciﬁcations which apply over the full operating temperature range, otherwise speciﬁcations are at TA = 25°C. (Note 9) VS = ±5V, VCM = 0V, unless otherwise noted.
PAGE 5
LT1818/LT1819 ELECTRICAL CHARACTERISTICS The l denotes the speciﬁcations which apply over the full operating temperature range, otherwise speciﬁcations are at TA = 25°C. (Note 9) VS = 5V, 0V; VCM = 2.5V, RL to 2.5V unless otherwise noted.
PAGE 6
LT1818/LT1819 ELECTRICAL CHARACTERISTICS Note 5: With ±5V supplies, slew rate is tested in a closed-loop gain of –1 by measuring the rise time of the output from –2V to 2V with an output step from –3V to 3V. With single 5V supplies, slew rate is tested in a closed-loop gain of –1 by measuring the rise time of the output from 1.5V to 3.5V with an output step from 1V to 4V.
PAGE 7
LT1818/LT1819 TYPICAL PERFORMANCE CHARACTERISTICS Output Voltage Swing vs Supply Voltage Open-Loop Gain vs Temperature 71 RL = 500Ω 65 RL = 500Ω –1.0 RL = 100Ω –1.5 –2.0 2.0 1.5 RL = 100Ω 1.
PAGE 8
LT1818/LT1819 TYPICAL PERFORMANCE CHARACTERISTICS Gain vs Frequency, A V = 2 10 Gain-Bandwidth and Phase Margin vs Supply Voltage Gain vs Frequency, A V = –1 5 RL = 500Ω 450 VS = ±5V TA = 25°C 400 GBW RL = 500Ω 0 GAIN (dB) 0 TA = 25°C –5 A = 2 V VS = ±5V RF = RG = 500Ω CF = 1pF –10 1M 10M FREQUENCY (Hz) –5 100M 100 40 PHASE MARGIN RL = 500Ω 10M FREQUENCY (Hz) 100M 100 +PSRR 60 40 20 Slew Rate vs Input Step TA =25°C AV = –1 V = ±5V 1600 RS = R = R = 500Ω F G L TA = 25°C VS = ±2.
PAGE 9
LT1818/LT1819 TYPICAL PERFORMANCE CHARACTERISTICS Distortion vs Frequency, A V = 2 Distortion vs Frequency, A V = –1 –60 DISTORTION (dB) DISTORTION (dB) –80 –70 2ND, RL = 500Ω –90 3RD, RL = 500Ω –100 AV = 2 VS = ±5V VO = 2VP-P –120 1M –80 10M 3RD, RL = 500Ω –90 3RD, RL = 100Ω –100 –110 2M 5M FREQUENCY (Hz) 2ND, RL = 500Ω –70 –80 3RD, RL = 100Ω –120 1M 2ND, RL = 100Ω –90 –100 3RD, RL = 500Ω AV = –1 VS = ±5V VO = 2VP-P –110 2ND, RL = 500Ω 10M 2M 5M FREQUENCY (Hz) –120 1M 2M 5M FREQ
PAGE 10
LT1818/LT1819 APPLICATIONS INFORMATION Layout and Passive Components load, a resistor of 10Ω to 50Ω must be connected between the output and the capacitive load to avoid ringing or oscillation (see RS in Figure 1). The feedback must still be taken directly from the output so that the series resistor will isolate the capacitive load to ensure stability. As with all high speed ampliﬁers, the LT1818/LT1819 require some attention to board layout.
PAGE 11
LT1818/LT1819 APPLICATIONS INFORMATION Slew Rate The slew rate of the LT1818/LT1819 is proportional to the differential input voltage. Highest slew rates are therefore seen in the lowest gain conﬁgurations. For example, a 6V output step with a gain of 10 has a 0.6V input step, whereas at unity gain there is a 6V input step. The LT1818/LT1819 is tested for slew rate at a gain of –1.
PAGE 12
LT1818/LT1819 TYPICAL APPLICATION Single Supply Differential ADC Driver 5V 10μF 18pF + VIN 51.1Ω 1/2 LT1819 5V – AIN+ 18pF 536Ω AIN– 536Ω – LTC1744 14 BITS 50Msps (SET FOR 2VP-P FULL SCALE) 18189 TA05 51.1Ω 1/2 LT1819 4.99k 18pF + 5V 4.99k 0.1μF Results Obtained with the Circuit of Figure 2 at 5MHz. FFT Shows 81dB Overall Spurious Free Dynamic Range 0 fIN = 5.
PAGE 13
LT1818/LT1819 SIMPLIFIED SCHEMATIC (One Ampliﬁer) V+ R1 +IN OUT –IN C V– 18189 SS 18189fb 13
PAGE 14
LT1818/LT1819 PACKAGE DESCRIPTION MS8 Package 8-Lead Plastic MSOP (Reference LTC DWG # 05-08-1660 Rev F) 0.889 p 0.127 (.035 p .005) 5.23 (.206) MIN 3.20 – 3.45 (.126 – .136) 0.42 p 0.038 (.0165 p .0015) TYP 3.00 p 0.102 (.118 p .004) (NOTE 3) 0.65 (.0256) BSC 8 7 6 5 0.52 (.0205) REF RECOMMENDED SOLDER PAD LAYOUT 0.254 (.010) 3.00 p 0.102 (.118 p .004) (NOTE 4) 4.90 p 0.152 (.193 p .006) DETAIL “A” 0o – 6o TYP GAUGE PLANE 1 0.53 p 0.152 (.021 p .006) DETAIL “A” 2 3 4 1.10 (.043) MAX 0.
PAGE 15
LT1818/LT1819 PACKAGE DESCRIPTION S5 Package 5-Lead Plastic TSOT-23 (Reference LTC DWG # 05-08-1635) 0.62 MAX 0.95 REF 2.90 BSC (NOTE 4) 1.22 REF 1.4 MIN 3.85 MAX 2.62 REF 2.80 BSC 1.50 – 1.75 (NOTE 4) PIN ONE RECOMMENDED SOLDER PAD LAYOUT PER IPC CALCULATOR 0.30 – 0.45 TYP 5 PLCS (NOTE 3) 0.95 BSC 0.80 – 0.90 0.20 BSC 0.01 – 0.10 1.00 MAX DATUM ‘A’ 0.30 – 0.50 REF 0.09 – 0.20 (NOTE 3) NOTE: 1. DIMENSIONS ARE IN MILLIMETERS 2. DRAWING NOT TO SCALE 3. DIMENSIONS ARE INCLUSIVE OF PLATING 4.
PAGE 16
LT1818/LT1819 PACKAGE DESCRIPTION S8 Package 8-Lead Plastic Small Outline (Narrow .150 Inch) (Reference LTC DWG # 05-08-1610) .189 – .197 (4.801 – 5.004) NOTE 3 .045 p.005 .050 BSC 8 .245 MIN 7 6 5 .160 p.005 .150 – .157 (3.810 – 3.988) NOTE 3 .228 – .244 (5.791 – 6.197) .030 p.005 TYP 1 RECOMMENDED SOLDER PAD LAYOUT .010 – .020 s 45o (0.254 – 0.508) .008 – .010 (0.203 – 0.254) 0o– 8o TYP .016 – .050 (0.406 – 1.270) NOTE: 1. DIMENSIONS IN .053 – .069 (1.346 – 1.752) .014 – .019 (0.355 – 0.
PAGE 17
LT1818/LT1819 REVISION HISTORY (Revision history begins at Rev B) REV DATE DESCRIPTION PAGE NUMBER B 5/10 Updated Order Information Section 2 18189fb Information furnished by Linear Technology Corporation is believed to be accurate and reliable. However, no responsibility is assumed for its use. Linear Technology Corporation makes no representation that the interconnection of its circuits as described herein will not infringe on existing patent rights.
PAGE 18
LT1818/LT1819 TYPICAL APPLICATION 80MHz, 20dB Gain Block + VIN 1/2 LT1819 – + VOUT 1/2 LT1819 432Ω – 432Ω 200Ω 200Ω –3dB BANDWIDTH: 80MHz 18189 TA03 20dB Gain Block Frequency Response Large-Signal Transient Response 25 20 GAIN (dB) 15 10 1V/DIV 5 0 –5 VS = ±5V TA = 25°C –10 100k 1M 10M FREQUENCY (Hz) 10ns/DIV 100M 18189 TA07 18189 TA04 RELATED PARTS PART NUMBER DESCRIPTION COMMENTS LT1395/LT1396/LT1397 Single/Dual/Quad 400MHz Current Feedback Ampliﬁers 4.