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Home > Products > Integrated Circuits (ICs) > Linear > Instrumentation, Op Amps, Buffer Amps

Texas Instruments LMH6518SQ/NOPB

Name: LMH6518SQ/NOPB
Brand: Texas Instruments
SKU: LMH6518SQ/NOPB
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: LMH6518SQ/NOPB

Manufacturer:: Texas Instruments

Category:: Instrumentation, Op Amps, Buffer Amps

Package:: 16-WFQFN Exposed Pad

Datasheet:: LMH6518SQ/NOPB.pdf

Description:: IC VARIABLE GAIN 1 CIRC 16WQFN

Quantity:: RFQ Add To RFQ list

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Product details

Overview

LMH6518SQ/NOPB from Texas Instruments is a digitally controlled variable gain amplifier (DVGA) with 40 dB gain range in 2 dB steps, −3 dB bandwidth of 900 MHz across all gains, and differential main/auxiliary outputs for oscilloscope trigger and ADC driver applications. It supports SPI programming, offers 8.5 mdB combined resolution with GSPS ADCs, and features overvoltage clamps for fast recovery.

For engineers reviewing the LMH6518SQ/NOPB datasheet, LMH6518SQ/NOPB pinout, LMH6518SQ/NOPB application, or LMH6518SQ/NOPB equivalent, key selection criteria include its 900 MHz flat bandwidth, dual-output timing alignment (≤100 ps propagation delay variation), auxiliary output common-mode control, and programmable bandwidth limiting (20–750 MHz or full BW).

Technical Context

The LMH6518SQ/NOPB implements a two-stage architecture: a digitally selectable preamplifier (high-gain or low-gain mode) followed by a 10-step 2 dB ladder attenuator, enabling precise gain control from −1.16 dB to 38.8 dB. Its differential signal path includes independent VCM and VCM_AUX inputs for main and auxiliary output common-mode voltage setting.

Bandwidth limiting is applied identically to both main and auxiliary outputs via a single programmable filter with seven settings (20/100/200/350/650/750 MHz or full BW). The device uses overvoltage clamps on both outputs to ensure sub-5 ns recovery from saturation, critical for high-fidelity transient capture in oscilloscope front-ends.

Key Specifications

Parameter	Value and Actual Design Meaning
Gain Range	−1.16 dB to 38.8 dB (40 dB total); enables full-scale input scaling from 6.8 mV_PP to 920 mV_PP into TI GSPS ADCs.
−3 dB Bandwidth	900 MHz at all gain settings; maintains flat frequency response without gain-dependent roll-off.
Rise/Fall Time	< 460 ps / < 450 ps; supports accurate reproduction of sub-nanosecond edges in high-speed digitizers.
Propagation Delay Variation	100 ps across gain settings; ensures stable timing alignment between main and auxiliary outputs.
Input-Referred Noise	0.98 nV/√Hz at maximum gain; preserves SNR in low-amplitude RF/IF signal chains.
Harmonic Distortion	HD2 = −50 dBc, HD3 = −53 dBc at 100 MHz; meets linearity requirements for precision measurement systems.
Power Consumption	210 mA @ VCC = 5 V (aux enabled); 165 mA (aux off); optimized for thermal management in dense PCB layouts.
SPI Interface Speed	10 MHz SCLK max; allows rapid gain updates synchronized with acquisition triggers in real-time systems.

Pinout & Package

The LMH6518SQ/NOPB is housed in a 16-pin WQFN package (RGH), 4 mm × 4 mm, with exposed thermal pad electrically connected to pins 5 and 8 (GND).

Pin/Terminal	Circuit Role	Design Meaning
+OUT AUX	Auxiliary positive differential output	Provides replica of main output for oscilloscope trigger circuitry; independently controllable common-mode voltage (VCM_AUX).
−OUT AUX	Auxiliary negative differential output	Completes auxiliary differential pair; matches main output timing (≤100 ps delay variation) and gain (±0.2 dB matching).
+IN / −IN	Differential analog input	Accepts dc-coupled signals; 150 kΩ \|\| 1.5 pF input impedance; CMVR = 1.9–3.1 V for ≥40 dB CMRR.
+OUT / −OUT	Main differential output	Drives ADC inputs directly; supports 800 mV_PP full-scale swing at ≤−40 dBc THD; clamped to 1.8 V per pin (VCM = 1.2 V).
VCM / VCM_AUX	Common-mode voltage control inputs	Analog inputs setting DC offset of main/auxiliary outputs; bias current ≤±10 nA enables high-impedance source compatibility.
VCC (pins 3,4)	Analog power supply	5 V ±5% supply; powers preamp and ladder stages; 210 mA typical draw at full power.
VDD (pin 12)	Digital power supply	3.3 V ±5% supply; powers SPI interface and logic; draws only 350 µA typical.
CS / SCLK / SDIO	SPI serial interface	Standard 3-wire SPI (active-low CS, 10 MHz max SCLK); SDIO bidirectional for 24-bit command/data transfers.
GND (pins 5,8)	Ground reference	Electrically tied to thermal pad; provides low-inductance return path for analog and digital currents.

Key Features

Feature	Design Value
Dual differential outputs with independent CM control	Enables simultaneous high-fidelity signal acquisition (main) and deterministic trigger generation (aux) without external level-shifting.
Programmable bandwidth limiting (7 settings)	Reduces out-of-band noise and aliasing before ADC sampling; identical filtering applied to both outputs ensures matched group delay.
Overvoltage clamps with <5 ns recovery	Prevents ADC saturation-induced dead time during large transient events; critical for real-time oscilloscope waveform reconstruction.
8.5 mdB effective gain resolution with GSPS ADC	Combines 2 dB DVGA steps with adjustable ADC full-scale range to achieve fine analog gain tuning for dynamic range optimization.
Gain accuracy ±0.75 dB and matching ±0.2 dB	Ensures repeatable amplitude calibration across temperature (−40°C to +85°C) and gain settings for metrology-grade instruments.
Low 0.98 nV/√Hz input noise at max gain	Maintains system SNR when amplifying weak RF/IF signals; complements high-performance ADCs like TI's ADC12DJ3200.

Applications

Oscilloscope Front-End Amplifier	Differential ADC Driver
Use Scenario: Amplifies probe-sensed analog signals prior to digitization in real-time digital storage oscilloscopes. IC Role / Device Role / Timing Role: Digitally controlled gain stage with auxiliary output feeding independent trigger path; main output drives ADC input with matched timing. Use Value: Enables automatic input range scaling across 40 dB while preserving sub-ns edge fidelity and ensuring trigger-event correlation within 100 ps.	Use Scenario: Conditions single-ended or differential sensor outputs for high-speed data converters in test equipment and communications receivers. IC Role / Device Role / Timing Role: Differential driver with programmable gain and bandwidth limiting; interfaces directly to TI GSPS ADCs (e.g., ADC12DJ5200RF) via 100 Ω differential load. Use Value: Delivers 800 mV_PP full-scale swing at ≤−40 dBc THD while suppressing harmonics and noise outside ADC Nyquist zone.
RF/IF Signal Chain Gain Control	Precision Medical Imaging Front-End
Use Scenario: Adjusts signal level in wideband RF receiver chains before downconversion or direct sampling. IC Role / Device Role / Timing Role: Wideband DVGA with 900 MHz flat response; used in IF sampling architectures where gain must remain stable across multi-hundred-MHz bandwidths. Use Value: Maintains constant −3 dB bandwidth and <±0.2 dB gain matching between main/aux paths, reducing calibration complexity in phased-array or spectrum analyzers.	Use Scenario: Amplifies low-amplitude ultrasound or MRI coil signals requiring high dynamic range and low distortion. IC Role / Device Role / Timing Role: Low-noise, high-linearity DVGA with 0.98 nV/√Hz input noise and −53 dBc HD3 at 100 MHz; dc-coupled for baseband imaging waveforms. Use Value: Preserves weak echo signal integrity while enabling programmable gain compensation for varying transducer sensitivities and tissue attenuation.

Oscilloscope Front-End Amplifier

Differential ADC Driver

Use Scenario: Amplifies probe-sensed analog signals prior to digitization in real-time digital storage oscilloscopes.

IC Role / Device Role / Timing Role: Digitally controlled gain stage with auxiliary output feeding independent trigger path; main output drives ADC input with matched timing.

Use Value: Enables automatic input range scaling across 40 dB while preserving sub-ns edge fidelity and ensuring trigger-event correlation within 100 ps.

Use Scenario: Conditions single-ended or differential sensor outputs for high-speed data converters in test equipment and communications receivers.

IC Role / Device Role / Timing Role: Differential driver with programmable gain and bandwidth limiting; interfaces directly to TI GSPS ADCs (e.g., ADC12DJ5200RF) via 100 Ω differential load.

Use Value: Delivers 800 mV_PP full-scale swing at ≤−40 dBc THD while suppressing harmonics and noise outside ADC Nyquist zone.

RF/IF Signal Chain Gain Control

Precision Medical Imaging Front-End

Use Scenario: Adjusts signal level in wideband RF receiver chains before downconversion or direct sampling.

IC Role / Device Role / Timing Role: Wideband DVGA with 900 MHz flat response; used in IF sampling architectures where gain must remain stable across multi-hundred-MHz bandwidths.

Use Value: Maintains constant −3 dB bandwidth and <±0.2 dB gain matching between main/aux paths, reducing calibration complexity in phased-array or spectrum analyzers.

Use Scenario: Amplifies low-amplitude ultrasound or MRI coil signals requiring high dynamic range and low distortion.

IC Role / Device Role / Timing Role: Low-noise, high-linearity DVGA with 0.98 nV/√Hz input noise and −53 dBc HD3 at 100 MHz; dc-coupled for baseband imaging waveforms.

Use Value: Preserves weak echo signal integrity while enabling programmable gain compensation for varying transducer sensitivities and tissue attenuation.

Equivalent & Alternatives

The following parts are listed as comparable options for similar digitally controlled variable gain amplifier applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
ADL5330ACPZ-R7	50 Ω single-ended RF input/output; 0.1–2.5 GHz bandwidth; analog gain control (voltage); no auxiliary output.	Optimized for RF transmitter/receiver gain control, not precision ADC driving or dual-output timing-critical applications.	Select when RF system integration requires 50 Ω impedance matching and analog control, not SPI-programmed gain with matched dual outputs.
MAX19723ETX+	Differential 50 Ω I/O; 0.1–1.2 GHz bandwidth; 25 dB gain range; integrated 12-bit DAC for gain control; no auxiliary output.	Targets broadband communications infrastructure; lacks overvoltage clamps and sub-5 ns recovery for oscilloscope use.	Select for compact, integrated RF gain control in base stations where DAC-based analog programming suffices and auxiliary timing path is unnecessary.

Compared with ADL5330ACPZ-R7 and MAX19723ETX+, the LMH6518SQ/NOPB uniquely delivers matched dual differential outputs with independent common-mode control, SPI programmability, and fast-recovery overvoltage clamps-making it the only option suited for high-fidelity oscilloscope front-ends requiring deterministic trigger correlation.

Availability

LMH6518SQ/NOPB is available at Aetrix Electronics and suitable for oscilloscope front-end amplifiers, differential ADC drivers, and RF/IF signal chain gain control requiring stable component supply, traceable sourcing, and long-term lifecycle support.

Supply support for LMH6518SQ/NOPB includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Texas Instruments is a global semiconductor leader specializing in analog, embedded processing, and high-performance signal chain solutions.

The LMH6518SQ/NOPB belongs to TI's high-speed amplifier product line, designed specifically for precision instrumentation, test & measurement, and wideband communications systems demanding programmable gain, ultra-wide bandwidth, and dual-output timing integrity.

FAQ

What is the gain adjustment resolution of the LMH6518SQ/NOPB when used with a TI GSPS ADC?

The LMH6518SQ/NOPB achieves an effective gain resolution of 8.5 mdB when its 2 dB digital gain steps are combined with adjustable full-scale range settings on compatible TI GSPS ADCs. This allows fine-grained input signal scaling from 6.8 mV_PP to 920 mV_PP, targeting a nominal 700 mV_PP at the ADC input. The LMH6518SQ/NOPB's gain accuracy of ±0.75 dB ensures consistent amplitude calibration across this extended range.

Does the LMH6518SQ/NOPB support independent bandwidth limiting for main and auxiliary outputs?

No-the LMH6518SQ/NOPB applies identical bandwidth limiting to both main and auxiliary outputs via a single programmable filter with seven settings: 20 MHz, 100 MHz, 200 MHz, 350 MHz, 650 MHz, 750 MHz, or full bandwidth. This ensures matched group delay and phase response between outputs, which is essential for oscilloscope trigger correlation. The LMH6518SQ/NOPB does not allow separate filter configuration for each output path.

How does the auxiliary output of the LMH6518SQ/NOPB differ from the main output in functionality?

The auxiliary output of the LMH6518SQ/NOPB replicates the main output signal with matched gain (±0.2 dB), timing (≤100 ps propagation delay variation), and bandwidth but features independent common-mode voltage control (VCM_AUX). It is intended primarily for oscilloscope trigger circuitry but can also serve as a secondary monitoring path. Unlike the main output, the auxiliary output is not rated for direct ADC driving at full performance-its HD2/HD3 are −48/−50 dBc vs. −50/−53 dBc for the main output at 100 MHz.

What power supply configurations are required for proper operation of the LMH6518SQ/NOPB?

The LMH6518SQ/NOPB requires two separate supplies: VCC = 5 V ±5% (pins 3 and 4) for analog circuitry, drawing up to 225 mA, and VDD = 3.3 V ±5% (pin 12) for digital SPI interface, drawing only 350 µA. Ground connections (pins 5 and 8) must be low-inductance and tied to the exposed thermal pad. Decoupling capacitors (e.g., 100 nF + 10 µF per supply) are mandatory close to the package to maintain 900 MHz stability and minimize digital crosstalk.

Can the LMH6518SQ/NOPB drive a 100 Ω differential ADC input directly without external termination?

Yes-the LMH6518SQ/NOPB is specified for 100 Ω differential loads and delivers 800 mV_PP full-scale swing at ≤−40 dBc THD into such a load. Its differential output impedance is tightly controlled at 100 Ω ±8 Ω, enabling direct connection to ADCs like TI's ADC12DJ3200 without external series or parallel termination. The LMH6518SQ/NOPB's output common-mode voltage is set via VCM and remains stable across temperature, simplifying interface design.

LMH6518SQ/NOPB Specifications

Product attributes: Attribute value

Manufacturer:: Texas Instruments

Series:: -

Package/Case:: 16-WFQFN Exposed Pad

Packaging:: Tape & Reel (TR)

Product Status:: Active

Amplifier Type:: Variable Gain

Number of Circuits:: 1

Output Type:: Differential

Slew Rate:: -

Gain Bandwidth Product:: -

-3db Bandwidth:: 900 MHz

Current - Input Bias:: 40 µA

Voltage - Input Offset:: -

Current - Supply:: 210mA

Current - Output / Channel:: -

Voltage - Supply Span (Min):: 4.75 V

Voltage - Supply Span (Max):: 5.25 V

Operating Temperature:: -40°C ~ 85°C

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: 16-WQFN (4x4)

LMH6518SQ/NOPB FAQ

1.How can I place an order for LMH6518SQ/NOPB through Aetrix?

Please submit a Request for Quotation (RFQ) for LMH6518SQ/NOPB on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.

2.Are the price and stock information for LMH6518SQ/NOPB reliable?

The price and inventory of LMH6518SQ/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LMH6518SQ/NOPB is usually 5 days.

3.What payment methods are accepted for LMH6518SQ/NOPB?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LMH6518SQ/NOPB transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for LMH6518SQ/NOPB?

LMH6518SQ/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your LMH6518SQ/NOPB order is processed, you will receive an email with the shipment details and tracking number.

Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.

5.How can I obtain technical support or documentation for LMH6518SQ/NOPB?

For technical support, including LMH6518SQ/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LMH6518SQ/NOPB requirements.

6.How does Aetrix verify that LMH6518SQ/NOPB is sourced from the original manufacturer or authorized distributors?

All LMH6518SQ/NOPB products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that LMH6518SQ/NOPB meets industry standards.

7.What is the process for return or replacement of LMH6518SQ/NOPB?

All LMH6518SQ/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LMH6518SQ/NOPB, returns or replacements are accepted under the following conditions:

1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.

2.The issue is reported within 90 days of delivery.

3.The LMH6518SQ/NOPB part is unused and in its original packaging.

Return procedure for LMH6518SQ/NOPB:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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