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Analog Devices Inc. AD1981BJST-LV
- Part No.:
- AD1981BJST-LV
- Manufacturer:
- Analog Devices Inc.
- Category:
- CODECS
- Package:
- 48-LQFP
- Datasheet:
-
AD1981BJST-LV.pdf
- Description:
- AC 97 SOUNDMAX CODEC
- Quantity:
- Payment:
- Shipping:
Inventory:2,232
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Product details
Overview
AD1981BJST-LV from Analog Devices is an AC '97 2.3–compliant stereo audio codec IC with integrated 20-bit DAC, 16-bit ADC, stereo headphone amplifier, S/PDIF output, and jack sense support. It operates with split supplies (5 V analog / 3.3 V digital), delivers >90 dB dynamic range, supports variable sample rates from 7.04 kHz to 48 kHz, and targets PC motherboard and notebook audio subsystems.
For engineers reviewing the AD1981BJST-LV datasheet, AD1981BJST-LV pinout, AD1981BJST-LV application, or AD1981BJST-LV equivalent, key selection criteria include AC '97 interface timing compliance, dual MIC preamp programmability, VREFOUT biasing capability for external amplifiers, and low-power operation modes including full codec standby (0 mA AVDD/DVDD draw).
Technical Context
The AD1981BJST-LV implements a fully AC '97 2.3–compliant digital audio interface with BIT_CLK (12.288 MHz), SYNC, SDATA_IN/OUT, and RESET signals. Its analog front-end includes three stereo line-level inputs (LINE_IN, AUX, CD), mono phone input, dual MIC inputs with 0–22.5 dB programmable gain, and high-fidelity CD differential input with ground sense.
Internally, it integrates two independent Σ-Δ converters (16-bit ADCs) and dual 20-bit Σ-Δ DACs, a digital equalizer core, mixer logic with per-channel gain/attenuation control, and power management registers enabling granular shutdown of ADC, DAC, or mixer blocks-reducing current draw to as low as 1.5 mA in ADC+DAC+Mixer low-power mode.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| DAC Resolution | 20-bit Σ-Δ architecture enabling 90 dB A-weighted dynamic range at full scale |
| ADC Resolution | 16-bit Σ-Δ architecture supporting 85 dB A-weighted dynamic range with −84 dB THD |
| Sample Rate Range | 7.04 kHz to 48 kHz in 1 Hz steps-enables flexible audio playback/recording across legacy and modern formats |
| Analog Supply | 5.0 V ±10% (AVDD); enables high-headroom line-out (1 Vrms) and headphone drive into 32 Ω |
| Digital Supply | 3.3 V ±10% (DVDD); compatible with standard PCI/AC '97 host controller I/O voltage levels |
| Dynamic Range | >90 dB SNR on CD-to-LINE_OUT path; meets premium PC audio fidelity requirements |
| Package | 48-lead LQFP (7 mm × 7 mm, 0.5 mm pitch); Pb-free option available per ordering code |
Pinout & Package
AD1981BJST-LV is housed in a 48-lead LQFP package (7 mm × 7 mm, 0.5 mm pitch) with exposed thermal pad. Pin functions are defined per Analog Devices Rev. C datasheet Figure 9 and Table 7, including dedicated AC '97 interface pins (BIT_CLK, SYNC, SDATA_IN/OUT), analog I/O (HP_OUT_L/R, LINE_OUT_L/R, MIC1/MIC2), jack sense inputs (JS0/JS1), and programmable VREFOUT (3.7 V nominal, 5 mA drive).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 5, 8 | SDATA_OUT / SDATA_IN | AC '97 serial data bidirectional stream: OUT carries codec register reads and DAC data; IN carries host writes and ADC data |
| 6 | BIT_CLK | AC '97 bit clock output (12.288 MHz) - synchronizes all frame-aligned data transfers between host and codec |
| 10 | SYNC | AC '97 frame sync signal - marks start of 256-bit frame containing 13 slots for control/data exchange |
| 11 | RESET | Active-low hardware reset - forces all internal registers to default state and initializes AC '97 link negotiation |
| 39, 41 | HP_OUT_L / HP_OUT_R | Direct-drive headphone outputs - each capable of 1 Vrms into 32 Ω with integrated amplifier and mute click suppression |
| 35, 36 | LINE_OUT_L / LINE_OUT_R | Line-level stereo outputs - 1 Vrms full-scale, 800 Ω output impedance, designed for connection to external amplifiers or speakers |
| 21, 22 | MIC1 / MIC2 | Stereo microphone inputs - support programmable 0–22.5 dB PGA gain and configurable mono/stereo recording paths |
| 17, 16 | JS0 / JS1 | Jack sense inputs - detect plug insertion/removal on headphone/speaker jacks to trigger automatic output routing |
| 28 | VREFOUT | Software-programmable reference output - adjustable up to 3.7 V, used to bias electret microphones or external power amps |
| 48 | SPDIF | S/PDIF digital audio output - supports 44.1 kHz and 48 kHz sample rates in 20-bit format for optical/coaxial transmission |
Key Features
| Feature | Design Value |
|---|---|
| AC '97 2.3 Compliance | Fully compliant interface with guaranteed timing margins (e.g., BIT_CLK jitter ≤2000 ps), enabling drop-in integration with Intel 8x0/9x0 and AMD SBxx AC '97 controllers |
| Integrated Stereo Headphone Amp | Capable of driving 32 Ω loads directly with <±5 mV mute click suppression-eliminates need for external buffer stages |
| Programmable VREFOUT | Configurable 2.25–3.70 V output with 5 mA drive-supports biasing of dual electret mics and external Class AB power amplifiers |
| Dual MIC Preamp with Gain Control | Independent 0–22.5 dB programmable gain per channel (1.5 dB steps), enabling robust noise rejection in laptop microphone arrays |
| Jack Sense Support | Dedicated JS0/JS1 inputs with interrupt capability-enables OS-level automatic switching between speakers, headphones, and headset modes |
| Low-Power Operation Modes | Seven discrete power-down states (e.g., PR0–PR6 bits) allow selective shutdown of ADC/DAC/mixer blocks-reducing idle current to 1.5 mA |
Applications
| PC Motherboard Audio | Notebook Integrated Audio |
|---|---|
Use Scenario: Primary audio subsystem on ATX/mATX motherboards interfacing with Intel ICH or AMD SB southbridge via AC '97 link. IC Role / Device Role / Timing Role: AC '97 slave codec providing synchronized ADC/DAC conversion, analog mixing, and headphone/line-out amplification. Use Value: Eliminates need for discrete op-amps and level-shifters; supports simultaneous playback/recording with >90 dB SNR and jack-sense–driven auto-routing. |
Use Scenario: Compact audio solution in space-constrained notebooks requiring low quiescent current and integrated headphone drive. IC Role / Device Role / Timing Role: Full-duplex audio codec managing mic input, speaker/headphone output, and S/PDIF passthrough under ACPI power management. Use Value: Reduces BOM count by integrating VREFOUT bias, jack sense, and 32 Ω headphone amp-enabling direct connection to 3.5 mm jacks without external components. |
| Desktop All-in-One Systems | Legacy Industrial HMI Terminals |
Use Scenario: Audio interface for touchscreen-based desktop PCs with built-in speakers, microphone array, and optical audio output. IC Role / Device Role / Timing Role: Central audio hub handling multi-source analog inputs (CD, AUX, LINE), stereo DAC output, and S/PDIF transmission. Use Value: Supports CD-quality differential CD input with ground sense and 20-bit S/PDIF output-preserving fidelity across analog and digital paths. |
Use Scenario: Audio subsystem in ruggedized industrial HMIs requiring long-lifecycle component support and deterministic AC '97 timing. IC Role / Device Role / Timing Role: AC '97-compliant audio transceiver managing voice prompts, operator microphone input, and mono speakerphone output. Use Value: Guaranteed AC '97 2.3 timing compliance (e.g., tRST_LOW ≥1.0 ms, tSYNC_HIGH ≥1.3 ms) ensures reliable boot-time enumeration in embedded Windows/Linux environments. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar AC '97 audio codec applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AD1981BSTZ | Same die, but packaged in 48-lead LQFP with standard (non-LV) supply tolerance: AVDD = 4.5–5.5 V, DVDD = 3.0–3.47 V | No LV-specific optimization; suitable where 3.3 V digital rail has tighter regulation or higher noise margin is acceptable | Select AD1981BSTZ only if board-level DVDD stability exceeds ±5% and no requirement for extended low-voltage digital operation |
| ALC203-GR | Realtek AC '97 codec; 18-bit DAC/ADC, no integrated headphone amp, requires external VREF and jack sense circuitry | Lacks VREFOUT, HP amp, and S/PDIF-requires additional components for equivalent functionality | Choose ALC203-GR only when cost sensitivity outweighs BOM simplification and performance requirements like >90 dB SNR or 20-bit DAC resolution |
Compared with AD1981BSTZ, AD1981BJST-LV provides enhanced digital supply tolerance (DVDD down to 3.0 V) for marginal 3.3 V rails, while ALC203-GR lacks integrated analog features-increasing design complexity and reducing SNR headroom by ~5 dB.
Availability
AD1981BJST-LV is available at Aetrix Electronics and suitable for PC motherboard design, notebook audio integration, and industrial HMI terminals requiring stable component supply, long-term lifecycle assurance, and AC '97 2.3 compliance.
Supply support for AD1981BJST-LV 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. is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, headquartered in Norwood, MA.
The AD1981B series was designed specifically for AC '97–based PC audio subsystems, emphasizing integration (headphone amp, VREFOUT, jack sense), low-power operation, and guaranteed timing compliance with Intel/AMD southbridge controllers.
FAQ
What is the primary interface standard supported by the AD1981BJST-LV?
The AD1981BJST-LV implements the AC '97 2.3 specification as a slave device, using BIT_CLK (12.288 MHz), SYNC, SDATA_IN, and SDATA_OUT signals to communicate with host controllers such as Intel ICH or AMD SB chipsets. It does not support I²S, PCM, or USB audio natively-its operation is strictly AC '97–defined.
Does the AD1981BJST-LV include an integrated headphone amplifier?
Yes, the AD1981BJST-LV integrates a stereo headphone amplifier capable of delivering 1 Vrms into 32 Ω loads. It features programmable volume control (0 dB to −46.5 dB in 1.5 dB steps), independent left/right mute, and hardware mute-click suppression (±5 mV deviation during mute transitions).
What are the power supply requirements for the AD1981BJST-LV?
The AD1981BJST-LV requires split supplies: analog AVDD = 4.5–5.5 V (typical 5.0 V) and digital DVDD = 3.0–3.47 V (typical 3.3 V). The "LV" suffix denotes extended lower limit on DVDD (3.0 V vs. 3.1 V in non-LV variants), improving compatibility with loosely regulated 3.3 V rails.
Can the AD1981BJST-LV support S/PDIF digital audio output?
Yes, the AD1981BJST-LV provides a dedicated SPDIF pin (Pin 48) that outputs consumer-grade S/PDIF format at 44.1 kHz and 48 kHz sample rates, using 20-bit data format. It does not support professional AES3, HDMI ARC, or TOSLINK physical layer-only electrical S/PDIF signaling.
How does the AD1981BJST-LV handle microphone input biasing?
The AD1981BJST-LV provides a programmable VREFOUT pin (Pin 28) that can be software-configured to deliver 2.25–3.70 V with up to 5 mA drive current. This output is intended to bias electret condenser microphones and external power amplifier input stages-replacing discrete bias resistors and regulators in the signal chain.
AD1981BJST-LV Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- AD1981B
- Package/Case:
- 48-LQFP
- Packaging:
- Bulk
- Product Status:
- Active
- Type:
- AC' 97, Stereo Audio
- Data Interface:
- AC'97, DSP, S/PDIF
- Resolution (Bits):
- 16 b, 20 b
- Number of ADCs / DACs:
- 4 / 2
- Sigma Delta:
- Yes
- S/N Ratio, ADCs / DACs (db) Typ:
- -
- Dynamic Range, ADCs / DACs (db) Typ:
- 85 / 90
- Voltage - Supply, Analog:
- 4.5V ~ 5.5V
- Voltage - Supply, Digital:
- 3V ~ 3.47V
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 48-LQFP (7x7)
AD1981BJST-LV FAQ
1.How can I place an order for AD1981BJST-LV through Aetrix?
Please submit a Request for Quotation (RFQ) for AD1981BJST-LV 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 AD1981BJST-LV reliable?
The price and inventory of AD1981BJST-LV are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AD1981BJST-LV is usually 5 days.
3.What payment methods are accepted for AD1981BJST-LV?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AD1981BJST-LV transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AD1981BJST-LV?
AD1981BJST-LV orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AD1981BJST-LV 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 AD1981BJST-LV?
For technical support, including AD1981BJST-LV datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AD1981BJST-LV requirements.
6.How does Aetrix verify that AD1981BJST-LV is sourced from the original manufacturer or authorized distributors?
All AD1981BJST-LV 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 AD1981BJST-LV meets industry standards.
7.What is the process for return or replacement of AD1981BJST-LV?
All AD1981BJST-LV units undergo pre-shipment inspection (PSI). If there is an issue with AD1981BJST-LV, 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 AD1981BJST-LV part is unused and in its original packaging.
Return procedure for AD1981BJST-LV:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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