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LTC6430-15

643015f

Typical applicaTion

FeaTures DescripTion

High Linearity Differential

RF/IF Amplifier/ADC Driver

The LTC

6430-15 is a differential gain block amplifier

designed to drive high resolution, high speed ADCs with

excellent linearity beyond 1000MHz and with low associ-

ated output noise. The LTC6430-15 operates from a single

5V power supply and consumes only 800mW.

In its differential configuration, the LTC6430-15 can directly

drive the differential inputs of an ADC. Using 1:2 baluns,

the device makes an excellent 50Ω wideband balanced

amplifier. While using 1:1.33 baluns, the device makes

a high fidelity 50MHz to 1000MHz 75Ω CATV amplifier.

The LTC6430-15 is designed for ease of use, requiring a

minimum of support components. The device is internally

matched to 100Ω differential source/load impedance. On-

chip bias and temperature compensation ensure consistent

performance over environmental changes.

The LTC6430-15 uses a high performance SiGe BiCMOS

process for excellent repeatability compared with similar

GaAs amplifiers. All A-grade LTC6430-15 devices are tested

and guaranteed for OIP3 at 240MHz. The LTC6430-15 is

housed in a 4mm × 4mm, 24-lead, QFN package with an

exposed pad for thermal management and low inductance.

For a single-ended 50Ω IF gain block with similar perfor-

mance, see the related LTC6431-15. .

Differential 16-Bit ADC Driver

OIP3 vs Frequency

applicaTions

50.0dBm OIP3 at 240MHz into a 100Ω Diff Load

NF = 3.0dB at 240MHz

20MHz to 2000MHz Bandwidth

15.2dB Gain

A-Grade 100% OIP3 Tested at 240MHz

1.0nV/√Hz Total Input Noise

S11 < –15dB Up to 1.2GHz

S22 < –15dB Up to 1.2GHz

>2.75V

P-P

Linear Output Swing

P1dB = 24.0dBm

Insensitive to V

Variation

100Ω Differential Gain-Block Operation

Input/Output Internally Matched to 100Ω Diff

Single 5V Supply

DC Power = 800mW

Unconditionally Stable

4mm × 4mm, 24-Lead QFN Package

Differential ADC Driver

Differential IF Amplifier

OFDM Signal Chain Amplifier

50Ω Balanced IF Amplifier

75Ω CATV Amplifier

700MHz to 800MHz LTE Amplifier

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

Technology Corporation. All other trademarks are the property of their respective owners.

643015 TA01a

LTC6430-15

SOURCE

= 100Ω

DIFFERENTIAL

50Ω

= 5V

CHOKES

1:2

BALUN

FILTER

LOAD

= 100Ω

DIFFERENTIAL

ADC

FREQUENCY (MHz)

OIP3 (dBm)

400 800 1000

200 600 1200

643015 TA01b

= 5V

OUT

= 2dBm/TONE

= Z

OUT

= 100Ω DIFF.

= 25°C

Summary of content (28 pages)

PAGE 1
LTC6430-15 High Linearity Differential RF/IF Amplifier/ADC Driver Description Features n n n n n n n n n n n n n n n n n 50.0dBm OIP3 at 240MHz into a 100Ω Diff Load NF = 3.0dB at 240MHz 20MHz to 2000MHz Bandwidth 15.2dB Gain A-Grade 100% OIP3 Tested at 240MHz 1.0nV/√Hz Total Input Noise S11 < –15dB Up to 1.2GHz S22 < –15dB Up to 1.2GHz >2.75VP-P Linear Output Swing P1dB = 24.
PAGE 2
LTC6430-15 Absolute Maximum Ratings Pin Configuration (Note 1) Total Supply Voltage (VCC to GND)...........................5.5V Amplifier Output Current (+OUT)..........................105mA Amplifier Output Current (–OUT)..........................105mA RF Input Power, Continuous, 50Ω (Note 2)........ +15dBm RF Input Power, 100µs Pulse, 50Ω (Note 2).......+20dBm Operating Temperature Range (TCASE) ....–40°C to 85°C Storage Temperature Range................... –65°C to 150°C Junction Temperature (TJ).....
PAGE 3
LTC6430-15 AC Electrical Characteristics The l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C, VCC = 5V, ZSOURCE = ZLOAD = 100Ω, unless otherwise noted (Note 3). Measurements are performed using Test Circuit A, measuring from 50Ω SMA to 50Ω SMA without de-embedding (Note 4).
PAGE 4
LTC6430-15 AC Electrical Characteristics The l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C, VCC = 5V, ZSOURCE = ZLOAD = 100Ω, unless otherwise noted (Note 3). Measurements are performed using Test Circuit A, measuring from 50Ω SMA to 50Ω SMA without de-embedding (Note 4). SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS Frequency = 300MHz S21 Differential Power Gain De-Embedded to Package 15.
PAGE 5
LTC6430-15 AC Electrical Characteristics The l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C, VCC = 5V, ZSOURCE = ZLOAD = 100Ω, unless otherwise noted (Note 3). Measurements are performed using Test Circuit A, measuring from 50Ω SMA to 50Ω SMA without de-embedding (Note 4). SYMBOL PARAMETER CONDITIONS OIP3 Output Third-Order Intercept Point POUT = 2dBm/Tone, Δf = 1MHz, ZO = 100Ω A-Grade B-Grade MIN 45.3 44.
PAGE 6
LTC6430-15 Typical Performance Characteristics TA = 25°C, VCC = 5V, ZSOURCE = ZLOAD = 100Ω, unless otherwise noted (Note 3). Measurements are performed using Test Circuit A, measuring from 50Ω SMA to 50Ω SMA without de-embedding (Note 4).
PAGE 7
LTC6430-15 Typical Performance Characteristics TA = 25°C, VCC = 5V, ZSOURCE = ZLOAD = 100Ω, unless otherwise noted (Note 3). Measurements are performed using Test Circuit A, measuring from 50Ω SMA to 50Ω SMA without de-embedding (Note 4). OIP3 vs RF Power Out/Tone Over Frequency OIP3 vs Frequency 50 48 46 46 44 44 42 VCC = 5V POUT = 2dBm/ TONE 38 ZIN = ZOUT = 100Ω DIFF.
PAGE 8
LTC6430-15 Typical Performance Characteristics TA = 25°C, VCC = 5V, ZSOURCE = ZLOAD = 100Ω, unless otherwise noted (Note 3). Measurements are performed using Test Circuit A, measuring from 50Ω SMA to 50Ω SMA without de-embedding (Note 4).
PAGE 9
LTC6430-15 Pin Functions GND (Pins 8, 14, 17, 23, Exposed Pad Pin 25): Ground. For best RF performance, all ground pins should be connected to the printed circuit board ground plane. The exposed pad (Pin 25) should have multiple via holes to an underlying ground plane for low inductance and good thermal dissipation. +OUT (Pin 18): Positive Amplifier Output Pin. A transformer with a center tap tied to VCC or a choke inductor tied to 5V supply is required to provide DC current and RF isolation.
PAGE 10
LTC6430-15 Differential Application Test Circuit A (Balanced Amp) RFIN 50Ω, SMA +OUT DNC GND DNC –OUT DNC DNC VCC GND R2 350Ω T2 2:1 • DNC DNC –IN C2 1000pF C3 1000pF T_DIODE LTC6430-15 DNC C8 60pF DNC DNC DNC DNC BALUN_A L1 560nH DNC T1 1:2 GND PORT INPUT +IN R1 350Ω VCC C7 60pF DNC C1 1000pF GND Test Circuit A C5 1nF C4 1000pF BALUN_A PORT OUTPUT RFOUT 50Ω, SMA L2 560nH C6 0.
PAGE 11
LTC6430-15 Applications Information The LTC6430-15 is a highly linear fixed-gain amplifier which is designed for ease of use. Both the input and output are internally matched to 100Ω differential source and load impedance from 20MHz to 1700MHz. Biasing and temperature compensation are also handled internally to deliver optimized performance. The designer need only supply input/output blocking capacitors, RF chokes and decoupling capacitors for the 5V supply.
PAGE 12
LTC6430-15 Applications Information and a larger 0.1µF capacitor to handle lower frequencies. Use ceramic capacitors of appropriate physical size for each capacitance value (e.g., 0402 for the 1000pF, 0805 for the 0.1µF) to minimize the equivalent series resistance (ESR) of the capacitor. Low Frequency Stability Most RF gain blocks suffer from low frequency instability.
PAGE 13
LTC6430-15 Applications Information Balanced Amplifier Circuit, 50Ω Input and 50Ω Output the circuit as a comprehensive protection for any passive element placed at the LTC6430-15 input. Its performance degradation at low frequencies can be mitigated by increasing the 60pF capacitor’s value. This balanced amplifier circuit is a replica of the Test Circuit A. It is useful for single-ended 50Ω amplifier requirements and is surprisingly wideband.
PAGE 14
LTC6430-15 Applications Information Driving the LTC2158, 14-Bit, 310Msps ADC with 1.25GHz of Bandwidth Boasting high linearity, low associated noise and wide bandwidth, the LTC6430-15 is well suited to drive high speed, high resolution ADCs with over a GHz of input bandwidth. To demonstrate its performance, the LTC643015 was used to drive an LTC2158 14-bit, 310Msps ADC with 1.25GHz of input bandwidth in an undersampling application.
PAGE 15
LTC6430-15 Applications Information VCM 5V 560nH 0402AF 60pF GUANELLA BALUN 1nF 150Ω VCC = 5V 49.9Ω 1nF 350Ω • • 100nH 0402CS LTC6430-15 LTC2158 MA/COM ETC1-1-13 643015 F03 200ps Figure 3. Wideband ADC Driver, LTC6430-15 Directly Driving the LTC2158 ADC VCM 5V 560nH 0402AF 60pF MINI-CIRCUITS ADTL2-18 2:1 BALUN 1nF VCC = 5V 49.9Ω 1nF 350Ω • • LTC6430-15 100nH 0402CS LTC2158 643015 F04 200ps Figure 4.
PAGE 16
LTC6430-15 Applications Information pads should be avoided within these distances. A 100nH shunt inductor at the ADC input approximates the complex conjugate of the ADC sampling circuit, and in doing so, improves power transfer and suppresses the low frequency difference products produced by direct sampling ADCs.
PAGE 17
LTC6430-15 Applications Information Figure 6. ADC Output: 2-Tone Test at 380MHz with 310Msps Sampling Rate Undersampled in the Third Nyquist Zone Figure 7. ADC Output: 1-Tone Test at 1000MHz with 307.
PAGE 18
LTC6430-15 Applications Information Figure 8. ADC Output: 2-Tone Test at 1000MHz with 307.2Msps Sampling Rate Undersampled in the Seventh Nyquist Zone Figure 9.
PAGE 19
LTC6430-15 Applications Information 50MHz to 1000MHz CATV Push-Pull Amplifier: 75Ω Input and 75Ω Output DNC GND DNC T_DIODE LTC6430-15 DNC –OUT BALUN_A = TC1.33-282+ FOR 50MHz TO 1000MHz MINI-CIRCUITS 1:1.33 BALUN DNC GND DNC DNC C2 0.047µF T2 1.33:1 100Ω • DIFFERENTIAL DNC DNC DNC BALUN_A C3 0.047µF +OUT VCC 100Ω DIFFERENTIAL L1 560nH DNC DNC DNC VCC +IN DNC GND RFIN 75Ω, CONNECTOR T1 1:1.33 –IN PORT INPUT GND C1 0.047µF C5 1000pF C4 0.
PAGE 20
LTC6430-15 Applications Information 50MHz to 1000MHz CATV Push-Pull Amplifier: 75Ω Input and 75Ω Output 0 –5 S22 MAG (dB) MAG (dB) –10 –15 S11 –20 –25 –30 0 200 400 600 800 FREQUENCY (MHz) 1000 1200 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 Figure 12. CATV Amplifier Circuit, Gain (S21) vs Frequency 10 S21 0 200 643015 F11 400 600 800 FREQUENCY (MHz) 1000 0 1200 0 200 643015 F12 400 600 800 FREQUENCY (MHz) 1000 1200 643015 F13 Figure 15.
PAGE 21
LTC6430-15 Applications Information 50MHz to 1000MHz CATV Push-Pull Amplifier: 75Ω Input and 75Ω Output 5 4 3 2 1 ECO __ REVISION HISTORY REV DESCRIPTION 1 1ST PROTOTYPE APPROVED JOHN C. DATE 06-26-12 D D L1=L2=560nH=COILCRAFT, PART#:0603LS-561XJLB C5 VCC 1000pF C10 1000pF 0603 C1 0.047uF U1 T4 C7 0.047uF R3 0 OPT DNC DNC GND 14 -OUT 13 C19 OPT MINI CIRCUIT TC1.33-282+ 3 4 1 6 C8 0.047uF OUT J2 L2 560nH CON-RF-75 OHM 12 -IN 8 7 C2 0.
PAGE 22
LTC6430-15 Applications Information 5 4 C13 1000pF C1 1000pF C R13 * R6 348 C7 VCC 1000pF C8 62pF R2 348 U1 R3 C2 1000pF *0603 B DNC C9 62pF 12 * GND R14 0603 DNC SMA-R 6 DNC C22 0.1uF C15 1000pF C4 1000pF T4 * J10 3 5 J8 1 R18 L22 OPT 1008 * -OUT 0603 VCC C23 0.
PAGE 23
LTC6430-15 Applications Information Figure 19.
PAGE 24
LTC6430-15 Differential S Parameters DD: Differential In to Differential Out 5V, ZDIFF = 100Ω, T = 25°C, De-Embedded to Package Pins, FREQUENCY (MHz) S11DD (Mag) S11DD (Ph) S21DD (Mag) S21DD (Ph) S12DD (Mag) S12DD (Ph) S22DD (Mag) S22DD (Ph) GTU (Max) STABILITY (K) 23.5 –14.79 –83.75 15.59 166.68 –18.75 9.35 –14.74 –66.63 15.88 0.99 83.5 –22.74 –107.27 15.16 170.23 –18.67 –3.01 –22.99 –48.57 15.21 1.07 143 –23.62 –121.45 15.14 167.23 –18.74 –8.44 –24.91 –37.10 15.
PAGE 25
LTC6430-15 Typical Applications 50Ω Input/Output Balanced Amplifier BALUN_A = ADT2-1T FOR 50MHz TO 300MHz BALUN_A = ADT2-1P FOR 300MHz TO 400MHz BALUN_A = ADTL2-18 FOR 400MHz TO 1300MHz ALL ARE MINI-CIRCUITS CD542 FOOTPRINT DNC DNC DNC –OUT DNC GND DNC R2 350Ω T2 2:1 • • 100Ω DIFFERENTIAL C4 1000pF BALUN_A DNC DNC –IN C2 1000pF C3 1000pF T_DIODE LTC6430-15 DNC C8 60pF VCC GND DNC BALUN_A DNC +OUT DNC DNC 100Ω DIFFERENTIAL RFIN 50Ω, SMA L1 560nH DNC VCC T1 1:2 GND PORT INPUT
PAGE 26
LTC6430-15 Typical Applications 75Ω 50MHz to 1000MHz CATV Amplifier T1 1:1.33 DNC DNC VCC DNC DNC GND DNC T_DIODE LTC6430-15 DNC • 100Ω DIFFERENTIAL C4 0.047µF DNC –OUT DNC GND DNC DNC C2 0.047µF C3 0.047µF T2 1.33:1 DNC DNC VCC BALUN_A L1 560nH +OUT GND 100Ω DIFFERENTIAL RFIN 75Ω, CONNECTOR GND DNC –IN PORT INPUT +IN C1 0.047µF • BALUN_A PORT OUTPUT RFOUT 75Ω, CONNECTOR L2 560nH BALUN_A = TC1.33-282+ FOR 50MHz TO 1000MHz MINI-CIRCUITS 1:1.33 C5 1000pF C6 0.
PAGE 27
LTC6430-15 Package Description Please refer to http://www.linear.com/designtools/packaging/ for the most recent package drawings. UF Package 24-Lead Plastic QFN (4mm × 4mm) (Reference LTC DWG # 05-08-1697 Rev B) 0.70 ±0.05 4.50 ±0.05 2.45 ±0.05 3.10 ±0.05 (4 SIDES) PACKAGE OUTLINE 0.25 ±0.05 0.50 BSC RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS 4.00 ±0.10 (4 SIDES) BOTTOM VIEW—EXPOSED PAD R = 0.115 TYP 0.75 ±0.05 PIN 1 NOTCH R = 0.20 TYP OR 0.35 × 45° CHAMFER 23 24 PIN 1 TOP MARK (NOTE 6) 0.
PAGE 28
LTC6430-15 Typical Application Wideband Balanced Amplifier 5V VCC = 5V RF 1:2 TRANSFORMER VIN LTC6430-15 RS 50Ω RSOURCE = 100Ω DIFFERENTIAL RLOAD = 100Ω DIFFERENTIAL 2:1 TRANSFORMER RL 50Ω 643015 TA05 Related Parts PART NUMBER DESCRIPTION COMMENTS Fixed Gain IF Amplifiers/ADC Drivers LTC6431-15 50Ω Gain Block IF Amplifier Single-Ended Version of LTC6431-15, 15.5dB Gain, 47dBm OIP3 at 240MHz into a 50Ω Load LTC6417 1.