AD6644 - 14-Bit 65 MSPS ADC | Analog Devices | Wideband
MPN: AD6644 ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $45 | $45.00 |
| 10 | $40.5 | $405.00 |
| 100 | $36 | $3,600.00 |
| 500 | $32.4 | $16,200.00 |
| 1,000 | $29 | $29,000.00 |
AD6644 Overview
An analog-to-digital converter (ADC) is a critical component in signal processing chains that converts continuous analog signals into discrete digital values for processing by digital systems. The AD6644 is a high-speed, high-resolution ADC, positioned in the hierarchy of data converters: ADC -> high-speed ADC -> wideband ADC -> IF-sampling ADC. It integrates a track-and-hold (T/H) circuit and reference, providing a complete conversion solution on-chip, which simplifies system design and reduces external component count.
Key features of the AD6644 include a 65 MSPS guaranteed sample rate, 100 dB multitone SFDR, and low power dissipation of 1.3 W. It features differential analog inputs, which improve common-mode noise rejection, and digital outputs that are 3.3 V CMOS-compatible, ensuring easy interfacing with modern digital logic. The device uses a three-stage subrange architecture, achieving high accuracy and speed while maintaining low power and small die size.
The AD6644 is built on Analog Devices' high speed complementary bipolar process (XFCB) and uses an innovative multipass circuit architecture. This design enables high dynamic performance, making it suitable for demanding applications such as digital receivers, cellular base stations, and test equipment. The device's wideband capability allows direct IF sampling, reducing the need for multiple downconversion stages.
Typical applications include multichannel, multimode receivers, software-defined radios, cellular infrastructure, and radar systems. The AD6644's high SFDR and low noise make it ideal for these applications where signal fidelity is critical. Its differential inputs and CMOS outputs simplify integration with FPGAs and DSPs.
When designing with the AD6644, careful attention to decoupling and grounding is essential to achieve optimal performance. The datasheet provides detailed recommendations for power supply decoupling and PCB layout to minimize noise and ensure accurate conversion.
Drop-in alternatives for AD6644 — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
AD6644-40
✅ Drop-In📋 Reference alternative (not in catalog)
AD6645
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
AD9246
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
AD6640
✅ Drop-In📋 Reference alternative (not in catalog)
AD9042
✅ Drop-In📋 Reference alternative (not in catalog)
AD6644 Maximum Ratings & Electrical Characteristics
| Resolution | 14 bits |
| Sample Rate (Guaranteed) | 65 MSPS |
| Sample Rate (40 MSPS Version) | 40 MSPS |
| Architecture | Three-stage subrange |
| Input Type | Differential |
| Output Format | Twos complement |
| Output Logic | 3.3 V CMOS-compatible |
| Multitone SFDR | 100 dB |
| Power Dissipation | 1.3 W |
| Package | 52-lead LQFP |
| Operating Temperature Range | -25°C to +85°C |
| Process Technology | XFCB (high speed complementary bipolar) |
| On-chip Track-and-Hold | Yes |
| On-chip Reference | Yes |
| Data Ready Output | Yes |
AD6644 Pin Configuration
| Pin 1 | AVDD — Analog power supply |
| Pin 2 | AVSS — Analog ground |
| Pin 3 | AIN+ — Positive differential analog input |
| Pin 4 | AIN- — Negative differential analog input |
| Pin 5 | AVSS — Analog ground |
| Pin 6 | AVDD — Analog power supply |
| Pin 7 | VREF — Voltage reference output/input |
| Pin 8 | AVSS — Analog ground |
| Pin 9 | CLK — Clock input |
| Pin 10 | AVDD — Analog power supply |
| Pin 11 | DRVDD — Digital output driver supply |
| Pin 12 | DRVSS — Digital output driver ground |
| Pin 13 | D0 — Digital output bit 0 (LSB) |
| Pin 14 | D1 — Digital output bit 1 |
| Pin 15 | D2 — Digital output bit 2 |
| Pin 16 | D3 — Digital output bit 3 |
| Pin 17 | D4 — Digital output bit 4 |
| Pin 18 | D5 — Digital output bit 5 |
| Pin 19 | D6 — Digital output bit 6 |
| Pin 20 | D7 — Digital output bit 7 |
| Pin 21 | D8 — Digital output bit 8 |
| Pin 22 | D9 — Digital output bit 9 |
| Pin 23 | D10 — Digital output bit 10 |
| Pin 24 | D11 — Digital output bit 11 |
| Pin 25 | D12 — Digital output bit 12 |
| Pin 26 | D13 — Digital output bit 13 (MSB) |
| Pin 27 | DRVSS — Digital output driver ground |
| Pin 28 | DRVDD — Digital output driver supply |
| Pin 29 | OTR — Out-of-range indicator |
| Pin 30 | DRVSS — Digital output driver ground |
| Pin 31 | DRVDD — Digital output driver supply |
| Pin 32 | NC — No connect |
| Pin 33 | NC — No connect |
| Pin 34 | NC — No connect |
| Pin 35 | NC — No connect |
| Pin 36 | NC — No connect |
| Pin 37 | NC — No connect |
| Pin 38 | NC — No connect |
| Pin 39 | NC — No connect |
| Pin 40 | NC — No connect |
| Pin 41 | NC — No connect |
| Pin 42 | NC — No connect |
| Pin 43 | NC — No connect |
| Pin 44 | NC — No connect |
| Pin 45 | NC — No connect |
| Pin 46 | NC — No connect |
| Pin 47 | NC — No connect |
| Pin 48 | NC — No connect |
| Pin 49 | NC — No connect |
| Pin 50 | NC — No connect |
| Pin 51 | NC — No connect |
| Pin 52 | NC — No connect |
Typical Applications
AD6644 is suitable for 6 applications: Multichannel Multimode Receivers, Cellular Base Stations, Software-Defined Radio (SDR), Radar Systems, Test and Measurement Equipment, Communications Infrastructure.
Multichannel Multimode Receivers
The AD6644 is designed for multichannel, multimode receivers, providing high dynamic range and wideband capability. Its 14-bit resolution and 65 MSPS sample rate enable direct IF sampling, reducing analog front-end complexity. The 100 dB SFDR ensures minimal intermodulation distortion, critical for dense signal environments. In such receivers, the AD6644 digitizes multiple channels simultaneously, allowing digital downconversion and channelization. Its low power dissipation of 1.3 W is advantageous in multi-receiver systems where thermal management is a concern. The differential inputs and CMOS outputs simplify interface to FPGAs or DSPs, enabling flexible digital processing.
Recommended
Cellular Base Stations
In cellular base stations, the AD6644 is used in the receive path to digitize wideband signals from multiple carriers. Its high SFDR and 14-bit resolution ensure that weak signals are not masked by intermodulation products from strong adjacent channels. The 65 MSPS sample rate supports oversampling, relaxing anti-aliasing filter requirements. The device's wideband input allows direct IF sampling, eliminating multiple downconversion stages and reducing component count. The 3.3 V CMOS outputs interface directly with baseband processors, simplifying digital design. The AD6644's low power dissipation is beneficial in high-density base station cards where power budgets are tight.
Recommended
Software-Defined Radio (SDR)
The AD6644 is part of the SoftCell transceiver chipset, making it ideal for software-defined radio applications. Its wideband capability allows a single ADC to digitize a broad spectrum, enabling flexible frequency planning. The 14-bit resolution provides the dynamic range needed to handle varying signal strengths, from weak signals to strong interferers. The high sample rate supports direct RF or IF sampling, simplifying the analog front end. The device's differential inputs reduce common-mode noise, improving signal integrity. In SDR systems, the AD6644's CMOS outputs connect directly to FPGAs for digital downconversion and demodulation, enabling reconfigurable radio architectures.
Recommended
Radar Systems
In radar systems, the AD6644 is used to digitize IF signals from the receiver, providing high resolution and wide bandwidth for target detection. Its 14-bit resolution ensures accurate amplitude and phase information, essential for Doppler processing. The 65 MSPS sample rate supports the bandwidth required for high-resolution radar. The device's high SFDR minimizes false targets caused by intermodulation products. The low power dissipation is advantageous in airborne or portable radar systems where power is limited. The differential inputs and CMOS outputs facilitate integration with digital signal processors, enabling real-time processing of radar returns.
Recommended
Test and Measurement Equipment
The AD6644 is suitable for test and measurement equipment such as spectrum analyzers and digitizers, where high dynamic range and bandwidth are required. Its 14-bit resolution and 65 MSPS sample rate allow accurate digitization of signals up to tens of MHz. The 100 dB SFDR ensures that spurious signals are minimized, providing clean measurements. The device's wideband input supports IF sampling, enabling direct digitization of intermediate frequencies. The low power dissipation is beneficial in portable instruments. The CMOS outputs interface easily with FPGAs or microprocessors for data processing and display.
Recommended
Communications Infrastructure
The AD6644 is used in communications infrastructure such as microwave links and satellite ground stations. Its high dynamic range and wideband capability enable reliable reception of modulated signals. The 14-bit resolution provides the necessary signal-to-noise ratio for high-order modulation schemes. The 65 MSPS sample rate supports wideband channels, increasing data throughput. The device's low power dissipation is important in remote or solar-powered installations. The differential inputs and CMOS outputs simplify interface to baseband processors, enabling efficient digital demodulation.
Recommended
Recommended Products Summary
Engineering reference data for AD6644 — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | AD6644-40 | AD6645 | AD9246 | AD6640 | AD9042 |
|---|---|---|---|---|---|---|
| Resolution | 14 bits | 14 bits | 14 bits | 14 bits | 12 bits | 12 bits |
| Sample Rate | 65 MSPS | 40 MSPS | 80 MSPS | 80 MSPS | 65 MSPS | 41 MSPS |
| Package | 52-lead LQFP | 52-lead LQFP | 52-lead LQFP | 52-lead LQFP | 52-lead LQFP | 52-lead LQFP |
| Brand | Analog Devices | Analog Devices | Analog Devices | Analog Devices | Analog Devices | Analog Devices |
| Input Type | Differential | Differential | Differential | Differential | Differential | Differential |
| Output Format | Twos complement | Twos complement | Twos complement | Twos complement | Twos complement | Twos complement |
Key Differentiators
- Higher resolution than predecessors (vs AD6640)
- Higher sample rate than AD9042 (vs AD9042)
- Low power dissipation (vs AD6645)
Design Notes
The AD6644 requires separate analog (AVDD) and digital (DRVDD) power supplies to minimize noise coupling. Use low-inductance decoupling capacitors (e.g., 0.1 uF and 10 uF) placed close to each power pin. The datasheet recommends a ferrite bead between the analog and digital supplies to isolate high-frequency noise. Ensure adequate power supply rejection by using linear regulators or low-noise LDOs for AVDD.
For optimal performance, use a solid ground plane and split analog and digital ground planes if necessary, connecting them at a single point. Place the ADC close to the signal source to minimize trace length. Route differential input traces as a matched pair with controlled impedance. The datasheet provides a recommended layout in the evaluation board section, which should be followed closely.
Avoid driving the analog inputs beyond the specified common-mode range, as this can cause distortion. Ensure the clock signal is clean and has low jitter, as clock jitter directly degrades SNR. The datasheet specifies a maximum clock jitter of [DATA_NEEDED] ps. Use a dedicated low-jitter clock source and buffer the clock signal close to the ADC. Also, do not leave unused digital outputs floating; tie them to ground or VDD as appropriate.
Compliance Information
Compliance information not explicitly stated in the provided data. Refer to the manufacturer's datasheet or product page for RoHS/REACH status.
