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Analog Devices Inc. LTC6420IUDC-20#PBF
- Part No.:
- LTC6420IUDC-20#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- Special Purpose Amplifiers
- Package:
- 20-WFQFN Exposed Pad
- Datasheet:
-
LTC6420IUDC-20#PBF.pdf
- Description:
- IC ADC DRIVER 20QFN
- Quantity:
- Payment:
- Shipping:
Inventory:3,313
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Product details
Overview
LTC6420IUDC-20#PBF from Analog Devices (formerly Linear Technology) is a dual, matched, high-speed differential amplifier optimized as an ADC driver for 12–16-bit converters. It delivers fixed 20dB (10V/V) gain, 1.8GHz –3dB bandwidth, ±0.1dB gain matching and ±0.1° phase matching at 100MHz, with rail-to-rail differential output swing and adjustable 1.1V–1.6V output common mode voltage - enabling direct DC-coupled interface to high-speed ADCs such as the LTC2285 in communications and instrumentation systems.
For engineers reviewing the LTC6420IUDC-20#PBF datasheet, LTC6420IUDC-20#PBF pinout, LTC6420IUDC-20#PBF application, or LTC6420IUDC-20#PBF equivalent, key selection criteria include channel-to-channel matching performance, VOCM-controlled common mode compatibility with ADC reference inputs, differential input impedance (200Ω), shutdown enable functionality per channel, and thermal robustness across –40°C to 85°C industrial operation.
Technical Context
The LTC6420IUDC-20#PBF integrates two fully independent differential amplifiers, each with internal 100Ω/1000Ω feedback networks setting fixed 10V/V gain and 200Ω differential input impedance. Its architecture employs on-chip output common mode control via dedicated VOCMA/VOCMB pins, decoupling output bias from input common mode and eliminating need for transformers or AC-coupling capacitors.
Each channel features independent ENABLEA/ENABLEB logic inputs for shutdown (high = high-Z output, 3μA supply current), 12.5Ω series output resistors for stability across load variations, and unconditional stability without external compensation. The device operates from a single 2.85V–3.5V supply, drawing 80mA per amplifier under active conditions.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Gain | 20dB (10V/V) - fixed, eliminates external gain-setting components and ensures consistent signal scaling into ADC full-scale range. |
| –3dB Bandwidth | 1.8GHz - supports wideband IF sampling up to 300MHz baseband with flat response and minimal group delay distortion. |
| Channel Matching | ±0.1dB gain / ±0.1° phase at 100MHz - enables precise I/Q signal processing and coherent dual-channel acquisition without calibration. |
| Noise Figure | 6.2dB at 100MHz - preserves SNR when driving high-resolution ADCs; input-referred noise is 2.2nV/√Hz. |
| OIP3 | 46dBm at 100MHz - provides high linearity for demanding RF receiver front-ends and broadband test equipment. |
| Output Common Mode Range | 1.1V to 1.6V - directly interfaces with VCM pins of LTC22xx, AD92xx, and similar 1.25V–1.5V-reference ADCs without level-shifting circuitry. |
| Supply Current | 80mA per amplifier at 3V - balances performance and power efficiency for dual-channel high-speed analog signal chains. |
Pinout & Package
Package: 20-lead 3mm × 4mm × 0.75mm plastic QFN (UDC) with exposed V– pad (Pin 21) requiring PCB soldering for thermal and electrical integrity.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| +INA, –INA +INB, –INB | Differential inputs (Ch A & Ch B) | Accept DC- or AC-coupled signals; 200Ω differential input impedance simplifies termination for 50Ω/200Ω sources. |
| +OUTA, –OUTA +OUTB, –OUTB | Differential outputs (Ch A & Ch B) | Rail-to-rail swing (0.2V–2.8V per side at VOCM=1.5V); 25Ω differential output impedance allows direct ADC connection or optional 25Ω series match. |
| VOCMA, VOCMB | Output common mode voltage control | High-impedance inputs setting 1.1V–1.6V output bias; bypass with 0.1μF capacitor to suppress noise coupling into ADC reference path. |
| ENABLEA, ENABLEB | Per-channel shutdown control | Active-low logic: low = enabled (80mA), high = shutdown (≤3μA), outputs high-Z - enables dynamic power management in multi-channel systems. |
| V+ A, V+ B V– (Pins 3,4,13,14,21) | Independent positive supplies & shared negative rail | V+ pins must be bypassed individually with 0.1μF + 1000pF; all V– pins and exposed pad connect to same ground plane for optimal PSRR and thermal dissipation. |
Key Features
| Feature | Design Value |
|---|---|
| Dual matched amplifiers | Guaranteed ±0.1dB gain and ±0.1° phase matching at 100MHz - critical for I/Q imbalance correction and MIMO receiver coherence. |
| VOCM-controlled output bias | Independent VOCMA/VOCMB pins enable precise alignment of differential output common mode to ADC VCM, eliminating transformer or resistor-divider bias networks. |
| Rail-to-rail differential output | Delivers ≥2VP-P swing while sourcing/sinking 20mA - maximizes ADC utilization without clipping in high-dynamic-range applications. |
| Per-channel enable/shutdown | ENABLEA/ENABLEB allow independent power gating - reduces system-level power by >95% per idle channel without affecting adjacent channel operation. |
| Unconditional stability | No external compensation required across all loads; 12.5Ω integrated output resistors ensure robustness with capacitive or mismatched ADC inputs. |
Applications
| Direct-Coupled ADC Interface | I/Q Signal Conditioning |
|---|---|
Use Scenario: Driving dual-channel 14-bit, 125Msps ADC LTC2285 in a software-defined radio front-end with DC-coupled analog signal path. IC Role / Device Role / Timing Role: Differential ADC driver providing matched gain, phase, and common mode alignment between I and Q paths to preserve quadrature integrity. Use Value: Eliminates transformers and AC-coupling caps, reducing board area by >30% and enabling sub-100ps inter-channel skew for accurate complex baseband reconstruction. |
Use Scenario: Amplifying and balancing I/Q outputs from a quadrature mixer in a satellite communications transceiver operating at L-band (1–2GHz). IC Role / Device Role / Timing Role: Dual-channel broadband gain block maintaining amplitude/phase coherence across 100MHz instantaneous bandwidth. Use Value: ±0.1dB/±0.1° matching ensures <−40dBc image rejection without digital calibration, meeting ETSI Class 3 spectral mask requirements. |
| IF Sampling Receiver | Broadband Test Instrumentation |
Use Scenario: Digitizing 70MHz IF signals in a diversity-receiver architecture with parallel ADC channels for interference mitigation. IC Role / Device Role / Timing Role: High-linearity differential amplifier delivering 46dBm OIP3 and –84dBc IMD3 to preserve weak-signal detectability amid strong blockers. Use Value: 1.8GHz bandwidth supports >100MHz instantaneous IF bandwidth, enabling real-time spectrum analysis without downconversion stages. |
Use Scenario: Signal conditioning stage in a 1GHz+ oscilloscope or arbitrary waveform generator output amplifier module. IC Role / Device Role / Timing Role: Low-noise (2.2nV/√Hz), low-distortion gain block with 0.8ns 1% settling time for fast edge fidelity. Use Value: 4500V/μs slew rate and 0.3GHz 0.1dB flatness bandwidth preserve rise times <350ps, supporting >500MHz small-signal step response accuracy. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar differential ADC driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC6400-20 | Single-channel, identical 20dB gain, 1.8GHz BW, but higher distortion (IMD3 = –86dBc) and no VOCM control. | Requires external common mode bias network; unsuitable for dual-channel matched systems without discrete matching. | Select when only one channel is needed and VOCM flexibility is not required - saves board space vs dual-amplifier solution. |
| LT6402-20 | Single-channel, lower 300MHz BW, 12mA supply current, –80dBc distortion at 25MHz; no VOCM pin. | Targeted at lower-frequency IF/RF applications (<100MHz); lacks precision matching and wideband linearity. | Choose for cost-sensitive, low-power, sub-100MHz designs where 1.8GHz bandwidth and dual-channel coherence are unnecessary. |
Compared with LTC6400-20 and LT6402-20, the LTC6420IUDC-20#PBF uniquely delivers dual-channel matching, VOCM-controlled DC coupling, and 1.8GHz bandwidth in a single 3mm×4mm package - making it the only option for high-fidelity, space-constrained, wideband dual-ADC interfaces requiring guaranteed inter-channel coherence.
Availability
LTC6420IUDC-20#PBF is available at Aetrix Electronics and suitable for high-speed data acquisition, satellite communications transceivers, and broadband test instrumentation requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for LTC6420IUDC-20#PBF 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
Analog Devices, Inc. (acquired Linear Technology in 2017) is a global leader in high-performance analog, mixed-signal, and DSP technologies, serving precision instrumentation, communications, and industrial markets.
The LTC6420 family was designed specifically for high-fidelity, wideband differential signal conditioning in ADC front-ends - emphasizing channel matching, VOCM control, and transformerless DC coupling for next-generation RF and measurement systems.
FAQ
What is the operating temperature range for the LTC6420IUDC-20#PBF?
The LTC6420IUDC-20#PBF is specified and guaranteed over the industrial temperature range of –40°C to +85°C. This rating applies to all DC and AC electrical characteristics in the datasheet, including gain matching, noise figure, and OIP3 performance - ensuring reliability in outdoor infrastructure, industrial automation, and aerospace-qualified systems where ambient temperatures vary widely.
Can the LTC6420IUDC-20#PBF drive ADCs without external transformers or coupling capacitors?
Yes. The LTC6420IUDC-20#PBF supports direct DC-coupled connection to ADCs via its VOCMA and VOCMB pins, which set output common mode voltage from 1.1V to 1.6V - matching typical ADC VCM inputs (e.g., LTC2285, AD9265). Its rail-to-rail differential output swing and 200Ω input impedance eliminate need for baluns or AC-coupling networks, simplifying layout and improving low-frequency response.
How does the ENABLE pin functionality work on the LTC6420IUDC-20#PBF?
ENABLEA and ENABLEB are independent active-low logic inputs: pulling either pin high (≥2.4V) places its respective amplifier into shutdown mode, reducing supply current to ≤3μA and forcing outputs to high-impedance state. Pulling low (≤0.8V) enables normal operation at 80mA per channel. Pins must never float - tie unused enables to ground via 10kΩ resistor to prevent erratic behavior.
What is the differential input impedance of the LTC6420IUDC-20#PBF, and how should it be terminated?
The LTC6420IUDC-20#PBF has a nominal differential input impedance of 200Ω. For 50Ω source systems, use shunt termination (e.g., 66.5Ω across inputs) or a wideband 1:4 balun as shown in the datasheet Figures 1 and 2. Termination must be placed adjacent to the input pins to minimize reflections; mismatch degrades return loss and increases harmonic distortion above 100MHz.
Is the LTC6420IUDC-20#PBF pin-compatible with other members of the LTC6420 family?
Yes - all LTC6420-x variants (e.g., LTC6420CUDC-20#PBF, LTC6420IUDC-20#TRPBF) share identical UDC-20 QFN pinout, footprint, and thermal pad configuration. The 'I' grade differs only in extended temperature screening and qualification; electrical specifications are identical to the 'C' grade except for guaranteed performance across –40°C to 85°C.
LTC6420IUDC-20#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 20-WFQFN Exposed Pad
- Packaging:
- Tube
- Product Status:
- Last Time Buy
- Type:
- ADC Driver
- Applications:
- Data Acquisition
- Mounting Type:
- Surface Mount
- Grade:
- -
- Qualification:
- -
- Supplier Device Package:
- 20-QFN (3x4)
LTC6420IUDC-20#PBF FAQ
1.How can I place an order for LTC6420IUDC-20#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC6420IUDC-20#PBF 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 LTC6420IUDC-20#PBF reliable?
The price and inventory of LTC6420IUDC-20#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC6420IUDC-20#PBF is usually 5 days.
3.What payment methods are accepted for LTC6420IUDC-20#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC6420IUDC-20#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC6420IUDC-20#PBF?
LTC6420IUDC-20#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC6420IUDC-20#PBF 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 LTC6420IUDC-20#PBF?
For technical support, including LTC6420IUDC-20#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC6420IUDC-20#PBF requirements.
6.How does Aetrix verify that LTC6420IUDC-20#PBF is sourced from the original manufacturer or authorized distributors?
All LTC6420IUDC-20#PBF 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 LTC6420IUDC-20#PBF meets industry standards.
7.What is the process for return or replacement of LTC6420IUDC-20#PBF?
All LTC6420IUDC-20#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC6420IUDC-20#PBF, 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 LTC6420IUDC-20#PBF part is unused and in its original packaging.
Return procedure for LTC6420IUDC-20#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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