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Texas Instruments VCA821IDR
- Part No.:
- VCA821IDR
- Manufacturer:
- Texas Instruments
- Category:
- Instrumentation, Op Amps, Buffer Amps
- Package:
- 14-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
VCA821IDR.pdf
- Description:
- IC VARIABLE GAIN 1 CIRC 14SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:4,700
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Product details
Overview
VCA821IDR from Texas Instruments is a DC-coupled, ultra-wideband voltage-controlled amplifier with linear-in-dB gain control, 710-MHz small-signal bandwidth at G = +2 V/V, >40-dB gain adjust range, and ±90 mA output current. It operates from ±5-V supplies and serves as a core gain-control element in AGC receivers, differential line receivers, and pulse amplitude compensation circuits.
For engineers reviewing the VCA821IDR datasheet, VCA821IDR pinout, VCA821IDR application, or VCA821IDR equivalent, key selection criteria include gain linearity (±0.3 dB over 1–2 V control range), 0.1-dB flatness to 135 MHz, slew rate of 2500 V/μs, and compatibility with SOIC-14 and VSSOP-10 packages for layout flexibility in high-speed analog signal chains.
Technical Context
The VCA821IDR integrates two input buffers and a current-feedback output stage with a multiplier core, enabling differential-to-single-ended conversion without external buffering. Its gain is set externally via RG and RF resistors, supporting maximum gains from 6 dB to 32 dB.
Gain control is linear in dB across a 0–2 V input (VG), with VCTRL0 = 0.85 V and VSLOPE = 90 mV per dB. The device maintains high accuracy (±0.4 dB absolute error at 20 dB max gain) and low distortion (–66 dBc 2nd-harmonic at 20 MHz) under ±5-V operation.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Small-signal bandwidth | 710 MHz at G = +2 V/V - enables RF and wideband IF signal processing up to UHF |
| Gain adjust range | >40 dB - supports dynamic range compression in AGC loops without cascading stages |
| Gain linearity error | ±0.3 dB (max, 25°C, 1–2 V VG) - ensures precise logarithmic control for RSSI and calibration |
| Slew rate | 2500 V/μs - preserves fast edge integrity in pulse-amplitude compensation applications |
| Output current | ±90 mA - drives 100-Ω loads directly, eliminating need for external buffer in line-receiver designs |
| Input noise density | 6.0 nV/√Hz - maintains SNR in low-level signal amplification paths |
| 0.1-dB gain flatness | to 135 MHz - guarantees amplitude consistency across video and broadband comms bands |
Pinout & Package
The VCA821IDR is available in SOIC-14 (8.65 mm × 3.91 mm) and VSSOP-10 (3.00 mm × 3.00 mm) packages. Pin functions are identical across both variants, with NC on SOIC Pin 13 and VREF omitted in VSSOP.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| +VIN | Noninverting input | Differential input node; accepts DC-coupled signals up to +1.6 V common-mode |
| –VIN | Inverting input | Differential input node; supports –2.1 V common-mode for bipolar signal handling |
| +RG / –RG | Gain set resistor terminals | Set nominal max gain (6–32 dB); current-limited to ±2.55 mA for stability |
| FB | Feedback resistor input | Connects to RF to define closed-loop gain; high-impedance node for precision setting |
| VG | Gain control voltage input | 0–2 V linear-in-dB control; 1.5 MΩ || 0.6 pF input impedance minimizes loading |
| VOUT | Single-ended output | Current-feedback architecture delivers ±3.6 V swing into 1 kΩ, ±3.3 V into 100 Ω |
| +VCC / –VCC | Power supply pins | ±5 V nominal (±3.5 V min, ±6 V max); quiescent current 32.5–36 mA |
| GND | Ground reference | Analog ground return; separate from power grounds in layout-critical high-speed designs |
Key Features
| Feature | Design Value |
|---|---|
| Differential input, single-ended output | Eliminates external balun or transformer in line-receiver interfaces |
| Linear-in-dB gain control | Enables direct RSSI voltage mapping without digital log-conversion circuitry |
| 710-MHz small-signal bandwidth | Supports direct amplification of IF signals up to 700 MHz in cable modem and DOCSIS systems |
| ±90 mA output drive | Drives 100-Ω coaxial cables or ADC inputs without series termination or buffer stages |
| 0.1-dB gain flatness to 135 MHz | Meets composite video dG/dP specs (<0.04% / <0.04°) without post-equalization |
Applications
| AGC Receiver with RSSI | Differential Line Receiver |
|---|---|
Use Scenario: Wideband receiver front-end where incoming signal strength varies over 60 dB; RSSI output required for automatic gain adjustment. IC Role / Device Role / Timing Role: Core VGA providing linear-in-dB gain control; VG input directly tied to RSSI detector output. Use Value: Achieves 40+ dB dynamic range compression with ±0.3 dB gain accuracy, enabling stable demodulator input levels across fading channels. | Use Scenario: Receiving balanced video or data signals over twisted-pair cabling with common-mode noise rejection. IC Role / Device Role / Timing Role: Differential-to-single-ended converter with programmable gain; rejects EMI-induced common-mode interference. Use Value: Delivers <0.04% differential gain and <0.04° differential phase error at 10 MHz, meeting SMPTE 259M video spec without external equalization. |
| Pulse Amplitude Compensation | Voltage-Tunable Active Filter |
Use Scenario: Compensating amplitude droop in fast-rising pulses transmitted through lossy PCB traces or cables. IC Role / Device Role / Timing Role: High-slew-rate VGA dynamically adjusting gain based on pulse timing or amplitude feedback. Use Value: 2500 V/μs slew rate preserves sub-2 ns rise times; 135 MHz 0.1-dB flatness ensures uniform gain across pulse spectrum. | Use Scenario: Tuning filter cutoff frequency in real time using analog voltage instead of switched capacitor banks. IC Role / Device Role / Timing Role: Gain-setting element in transconductance-based filter topologies (e.g., Tow-Thomas biquad). Use Value: Linear-in-dB control allows exponential tuning law for octave-per-volt filter response, simplifying control loop design. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar variable gain amplifier applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| VCA824IDR | Same architecture and pinout; optimized for 420-MHz bandwidth at G = +40 dB, lower input noise (5.5 nV/√Hz) | Better suited for higher-gain, lower-noise IF amplification where 710-MHz bandwidth is not required | Select VCA824IDR when prioritizing noise performance over maximum small-signal bandwidth |
| VCA822IDR | Identical SOIC-14 package; 150-MHz bandwidth at G = +10 V/V, lower quiescent current (26 mA) | Targeted at cost-sensitive, medium-bandwidth applications like baseband audio or sensor signal conditioning | Choose VCA822IDR for reduced power consumption and simpler thermal management in non-RF designs |
Compared with VCA821IDR, VCA824IDR trades 710-MHz bandwidth for improved noise floor, while VCA822IDR reduces speed and power for less demanding signal chains - all three share identical gain control interface and layout footprint in SOIC-14.
Availability
VCA821IDR is available at Aetrix Electronics and suitable for AGC receivers, differential line receivers, pulse amplitude compensation systems, and voltage-tunable active filters requiring stable component supply across industrial temperature ranges (–40°C to +85°C).
Supply support for VCA821IDR 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 delivering analog, embedded processing, and connectivity solutions for industrial, automotive, and communications markets.
The VCA821IDR belongs to TI's high-speed variable gain amplifier product line, engineered for precision gain control in wideband RF, video, and instrumentation signal chains where linear-in-dB response and DC coupling are essential.
FAQ
What is the maximum gain-setting range supported by the VCA821IDR?
The VCA821IDR supports a maximum gain-adjust range exceeding 40 dB, with nominal maximum gain configurable between 6 dB and 32 dB using external resistors RG and RF. At 20 dB maximum gain, it achieves gain from +20 dB (VG = +2 V) down to less than –20 dB (VG = 0 V), verified across –40°C to +85°C operating temperature.
Does the VCA821IDR require external output buffering for 100-Ω loads?
No, the VCA821IDR does not require external output buffering for 100-Ω loads. It delivers ±90 mA output current and ±3.3 V output voltage swing into 100 Ω at ±5-V supplies, enabling direct drive of coaxial cables, ADC inputs, or downstream op-amps without additional gain stages.
How does gain linearity perform across temperature for the VCA821IDR?
The VCA821IDR maintains ±0.6 dB absolute gain error over –40°C to +85°C at 20 dB maximum gain and VG = +2 V. Gain linearity deviation remains within ±0.3 dB from 1 V to 2 V control voltage at +25°C, degrading only marginally to ±0.5 dB across 0°C to 70°C - critical for stable RSSI and calibration accuracy.
Can the VCA821IDR operate from asymmetric supply voltages?
No, the VCA821IDR requires symmetric ±5-V supplies for specified performance. Absolute maximum ratings allow ±6.5 V, but recommended operating conditions specify ±5 V (±3.5 V minimum, ±6 V maximum). Asymmetric rails degrade CMRR, output swing symmetry, and gain accuracy - confirmed in Electrical Characteristics tables.
What package options are available for the VCA821IDR and how do they affect thermal performance?
The VCA821IDR is offered in SOIC-14 (D package) and VSSOP-10 (DGS package). SOIC-14 has RθJA = 90.3°C/W; VSSOP-10 has RθJA = 173.1°C/W. Both support full-spec operation at +85°C ambient, but SOIC-14 enables higher power dissipation in space-constrained layouts due to superior thermal resistance.
VCA821IDR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 14-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Amplifier Type:
- Variable Gain
- Number of Circuits:
- 1
- Output Type:
- -
- Slew Rate:
- 2500V/µs
- Gain Bandwidth Product:
- -
- -3db Bandwidth:
- 710 MHz
- Current - Input Bias:
- 19 µA
- Voltage - Input Offset:
- 4 mV
- Current - Supply:
- 34mA
- Current - Output / Channel:
- 90 mA
- Voltage - Supply Span (Min):
- 7 V
- Voltage - Supply Span (Max):
- 12 V
- Operating Temperature:
- -40°C ~ 85°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 14-SOIC
VCA821IDR FAQ
1.How can I place an order for VCA821IDR through Aetrix?
Please submit a Request for Quotation (RFQ) for VCA821IDR 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 VCA821IDR reliable?
The price and inventory of VCA821IDR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for VCA821IDR is usually 5 days.
3.What payment methods are accepted for VCA821IDR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for VCA821IDR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for VCA821IDR?
VCA821IDR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your VCA821IDR 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 VCA821IDR?
For technical support, including VCA821IDR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your VCA821IDR requirements.
6.How does Aetrix verify that VCA821IDR is sourced from the original manufacturer or authorized distributors?
All VCA821IDR 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 VCA821IDR meets industry standards.
7.What is the process for return or replacement of VCA821IDR?
All VCA821IDR units undergo pre-shipment inspection (PSI). If there is an issue with VCA821IDR, 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 VCA821IDR part is unused and in its original packaging.
Return procedure for VCA821IDR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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