My Inquiry
My Account
Texas Instruments LM4550BVH
- Part No.:
- LM4550BVH
- Manufacturer:
- Texas Instruments
- Category:
- CODECS
- Package:
- 48-LQFP
- Datasheet:
-
LM4550BVH.pdf
- Description:
- IC AC '97 AUDIO CODEC 48-LQFP
- Quantity:
- Payment:
- Shipping:
Inventory:1,047
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
LM4550BVH from Texas Instruments is an AC '97 Rev 2.1–compliant multi-channel audio codec featuring dual 18-bit sigma-delta ADCs and DACs, stereo headphone amplifier with independent gain control, TI 3D Sound enhancement, and sample rate conversion from 4 kHz to 48 kHz in 1 Hz steps. It delivers 90 dB ADC dynamic range, 89 dB DAC dynamic range, and supports up to 6 DAC channels in multi-codec systems for PC audio subsystems.
For engineers reviewing the LM4550BVH datasheet, LM4550BVH pinout, LM4550BVH application, or LM4550BVH equivalent, this page provides verified technical context, real-world interface roles, validated pin functions, confirmed analog/digital supply requirements (AVDD: 4.2–5.5 V, DVDD: 3–5.5 V), and direct alternatives for AC Link–based audio system design.
Technical Context
The LM4550BVH implements a full AC '97 Rev 2.1 digital audio interface with BIT_CLK (12.288 MHz), SYNC (48 kHz frame marker), SDATA_IN (codec-to-controller PCM/status), and SDATA_OUT (controller-to-codec PCM/control). It uses separate 18-bit sigma-delta converters for ADC and DAC paths, each with A-weighted dynamic range ≥89 dB (DAC) and ≥90 dB (ADC).
Analog functionality includes a programmable stereo mixer with 4 stereo + 4 mono inputs (CD_L/R, LINE_IN_L/R, AUX_L/R, VIDEO_L/R, MIC1/MIC2, PHONE, PC_BEEP), TI 3D Sound circuitry (enabled via register bit D13), and stereo headphone output (HP_OUT_L/R) with dedicated volume control (0 dB to –46.5 dB in 1.5-dB steps) and HP_OUT_C reference pin.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| ADC Resolution | 18-bit sigma-delta - enables high-fidelity digitization of microphone and line inputs with ≥90 dB dynamic range. |
| DAC Resolution | 18-bit sigma-delta - delivers low-noise analog outputs to LINE_OUT and HP_OUT with ≥89 dB dynamic range. |
| Sample Rate Conversion | 4 kHz to 48 kHz in 1 Hz increments - allows flexible clock domain bridging between non-synchronous audio sources and AC Link timing. |
| Headphone Amp THD+N | 0.02% typical at 50 mW into 32Ω - ensures clean playback without audible distortion in portable or desktop headphone outputs. |
| Analog Supply Range | AVDD = 4.2 V to 5.5 V - supports standard 5 V analog rail; AVSS1/AVSS2 required for dual analog ground separation. |
| Digital Supply Range | DVDD = 3 V to 5.5 V - compatible with both 3.3 V and 5 V logic domains; DVSS1/DVSS2 required for digital ground isolation. |
| Operating Temperature | −40°C ≤ TA ≤ 85°C - qualified for industrial and extended-temperature PC motherboard and embedded audio applications. |
Pinout & Package
LQFP-48 package (7.00 mm × 7.00 mm), thermally enhanced with exposed pad; requires proper analog/digital ground partitioning and 24.576 MHz crystal (XTL_IN/XTL_OUT) for primary mode operation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| HP_OUT_L / HP_OUT_R | Stereo headphone output | Line-level (1 Vrms) buffered outputs with independent 1.5-dB-step volume control; require HP_OUT_C AC ground reference. |
| LINE_OUT_L / LINE_OUT_R | Stereo line output | 1 Vrms nominal outputs driven from stereo mix; mute/attenuation controlled by Master Volume register (02h). |
| MIC1 / MIC2 | Microphone inputs | Support programmable 0 dB or 20 dB boost amplification; selectable per channel for ADC conversion or stereo mixing. |
| BIT_CLK / SYNC / SDATA_IN / SDATA_OUT | AC Link interface signals | Compliant with AC '97 Rev 2.1 timing; BIT_CLK = 12.288 MHz (primary) or input (secondary); SYNC marks 256-cycle frames. |
| ID0# / ID1# / CIN | Multi-codec addressing & chaining | Configure Primary/Secondary identity (ID0#/ID1#); CIN enables TI-specific daisy-chaining of multiple LM4550Bs on single SDATA_IN line. |
| VREF / VREF_OUT | Internal reference | VREF = 2.16 V nominal internal reference; VREF_OUT supplies up to 5 mA - usable for biasing electret microphones. |
Key Features
| Feature | Design Value |
|---|---|
| AC '97 Rev 2.1 compliance | Fully implements AC Link protocol including controller-to-codec and codec-to-controller frame structures, register map, and timing - interoperable with Intel AC'97 host controllers. |
| TI 3D Sound enhancement | Fixed-depth stereo widening circuit activated via General Purpose register bit D13; uses 3DP/3DN pins with 0.022 µF capacitor - improves perceived soundstage without DSP overhead. |
| Multi-codec chaining | Enables up to 6 DAC channels using TI's proprietary chain-in feature (CIN pin); eliminates need for multiple SDATA_IN lines when cascading LM4550Bs for surround sound. |
| PC Beep passthrough | During Cold Reset (RESET# active low), PC_BEEP input is hardwired to LINE_OUT_L/R - ensures BIOS POST tones are audible before driver initialization. |
| Extended power management | Separate analog/digital shutdown modes (PR6543210 register); analog shutdown draws only 70 µA, digital shutdown draws 19 µA - reduces idle power in portable systems. |
Applications
| Desktop PC Audio Subsystem | Portable PC MDC Audio |
|---|---|
Use Scenario: Integrated audio on PCI or AMR add-in cards with AC Link–capable chipset. IC Role / Device Role / Timing Role: Primary AC '97 codec handling full-duplex stereo ADC/DAC, analog mixing, and headphone amplification under AC Link timing control. Use Value: Delivers 90 dB ADC/89 dB DAC performance with TI 3D Sound and PC Beep passthrough - meets PC99 compliance and user-facing audio quality targets. |
Use Scenario: Audio solution on Mobile Daughter Card (MDC) in notebook platforms with AC Link support. IC Role / Device Role / Timing Role: Secondary codec configured via ID0#/ID1#, synchronized to primary controller's BIT_CLK and SYNC - enables compact, low-pin-count audio expansion. Use Value: Supports 4–6 DAC channel configurations via TI chaining; low quiescent current (19 µA digital shutdown) extends battery life during audio standby. |
| Automotive Telematics Head Unit | Industrial Embedded Audio Gateway |
Use Scenario: Voice/audio processing module in automotive infotainment systems requiring microphone input, line output, and headphone drive. IC Role / Device Role / Timing Role: Audio interface bridging MCU-based voice recognition engine (via AC Link) to analog sensors (MIC1/MIC2) and actuators (HP_OUT_L/R, LINE_OUT_L/R). Use Value: −40°C to 85°C operating range and robust ESD rating (±2000 V HBM) ensure reliability in vehicle cabin environments; VREF_OUT powers electret mics directly. |
Use Scenario: Audio I/O node in industrial HMI or medical device with isolated analog/digital domains and strict EMC requirements. IC Role / Device Role / Timing Role: Isolated audio transceiver with separate AVDD/AVSS and DVDD/DVSS supplies, differential-capable HP_OUT_C reference, and grounded NC pins for noise suppression. Use Value: Dual analog ground (AVSS1/AVSS2) and dual digital ground (DVSS1/DVSS2) enable PCB-level signal integrity optimization; LQFP-48 thermal resistance (74°C/W) supports convection-cooled enclosures. |
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 |
|---|---|---|---|
| ALC202A | Realtek AC '97 Rev 2.1 codec; 18-bit ADC/DAC; no integrated headphone amp; requires external amplifier for HP drive. | Targeted at cost-sensitive desktop motherboards where headphone output is handled off-chip; lacks TI 3D Sound and PC Beep passthrough. | Select when system already includes discrete headphone amplifier and TI-specific features are unnecessary. |
| AD1885 | Analog Devices AC '97 Rev 2.1 codec; 20-bit ADC/DAC; supports 96 kHz sampling; no TI chaining or 3D Sound. | Used in high-end audio workstations requiring extended dynamic range (96 dB ADC) and higher sample rates; incompatible with TI's CIN daisy-chain topology. | Select when >48 kHz sampling or >90 dB dynamic range is mandatory, and multi-codec chaining is not required. |
Compared with ALC202A and AD1885, the LM4550BVH uniquely integrates stereo headphone amplification with TI 3D Sound and hardware-accelerated multi-codec chaining - reducing BOM count and enabling compact 6-channel surround solutions without external logic or additional data lines.
Availability
LM4550BVH is available at Aetrix Electronics and suitable for desktop PC audio subsystems, portable MDC implementations, automotive telematics head units, and industrial embedded audio gateways requiring stable component supply, long-lifecycle support, and AC '97 Rev 2.1 compliance.
Supply support for LM4550BVH 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 company specializing in analog, embedded processing, and connectivity technologies, with leadership in audio signal chain ICs since the 1990s.
The LM4550BVH belongs to TI's AC '97 audio codec product line, designed specifically to deliver PC99-compliant, high-fidelity audio subsystems for desktop, mobile, and embedded platforms with minimal external components.
FAQ
What is the function of the CIN pin on the LM4550BVH?
The CIN pin on the LM4550BVH enables TI's proprietary codec chaining feature. When configured via the Chain-In Control register (74h), it allows the LM4550BVH to pass through SDATA_IN from another codec instead of driving its own - supporting up to 6 DAC channels across multiple LM4550BVH devices sharing a single controller SDATA_IN line. This eliminates additional serial data routing in multi-codec surround sound systems.
Does the LM4550BVH support both 3.3 V and 5 V digital supplies?
Yes, the LM4550BVH supports DVDD from 3 V to 5.5 V, making it compatible with both 3.3 V and 5 V digital logic domains. DVDD1 (pin 1) and DVDD2 (pin 9) must be decoupled independently, and DVSS1/DVSS2 grounds must be kept separate from analog grounds to maintain SNR. The device operates correctly across this full range without configuration changes.
How does the LM4550BVH handle microphone inputs with different sensitivity levels?
The LM4550BVH provides programmable 0 dB or 20 dB gain on MIC1 and MIC2 inputs via the Mic Volume register (0Eh). At 20 dB gain, nominal input is 0.1 Vrms (suitable for low-output electret mics); at 0 dB gain, nominal input is 1 Vrms (for line-level or amplified mic signals). The boost amplifier output feeds both ADC channels and stereo mixers, enabling flexible recording and monitoring paths within the LM4550BVH.
Can the LM4550BVH operate without an external crystal?
No - the LM4550BVH requires a 24.576 MHz fundamental-mode crystal connected between XTL_IN (pin 2) and XTL_OUT (pin 3) for primary mode operation. In secondary mode, XTL_IN may accept an external 24.576 MHz oscillator, but the crystal oscillator circuit remains mandatory for accurate AC Link timing synchronization. Leaving XTL_IN open disables clock generation and prevents functional operation.
What is the purpose of the HP_OUT_C pin on the LM4550BVH?
The HP_OUT_C pin on the LM4550BVH serves as the AC ground reference for the stereo headphone outputs HP_OUT_L and HP_OUT_R. It must be capacitively coupled to analog ground with short PCB traces to minimize noise and maximize PSRR. In non-stereo applications, HP_OUT_C can also provide common-mode feedback when configuring HP_OUT_L/R as a differential pair - improving rejection of supply and EMI noise in sensitive audio paths.
LM4550BVH Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 48-LQFP
- Packaging:
- Bulk
- Product Status:
- Not For New Designs
- Type:
- Audio, AC '97
- Data Interface:
- Serial
- Resolution (Bits):
- 18 b
- Number of ADCs / DACs:
- 2 / 2
- Sigma Delta:
- Yes
- S/N Ratio, ADCs / DACs (db) Typ:
- -
- Dynamic Range, ADCs / DACs (db) Typ:
- 90 / 89
- Voltage - Supply, Analog:
- 4.2V ~ 5.5V
- Voltage - Supply, Digital:
- 3V ~ 5.5V
- Operating Temperature:
- -40°C ~ 85°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 48-LQFP (7x7)
LM4550BVH FAQ
1.How can I place an order for LM4550BVH through Aetrix?
Please submit a Request for Quotation (RFQ) for LM4550BVH 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 LM4550BVH reliable?
The price and inventory of LM4550BVH are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM4550BVH is usually 5 days.
3.What payment methods are accepted for LM4550BVH?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM4550BVH transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM4550BVH?
LM4550BVH orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM4550BVH 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 LM4550BVH?
For technical support, including LM4550BVH datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM4550BVH requirements.
6.How does Aetrix verify that LM4550BVH is sourced from the original manufacturer or authorized distributors?
All LM4550BVH 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 LM4550BVH meets industry standards.
7.What is the process for return or replacement of LM4550BVH?
All LM4550BVH units undergo pre-shipment inspection (PSI). If there is an issue with LM4550BVH, 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 LM4550BVH part is unused and in its original packaging.
Return procedure for LM4550BVH:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LM4550BVH Tags
-
NAU88C22YG
Nuvoton Technology Corporation
-
TLV320AIC3100IRHBR
Texas Instruments
-
DA7212-01UM2
Renesas
-
NAU8810YG
Nuvoton Technology Corporation
-
DA7218-00U32
Renesas
-
CMX655DQ6-TR1K
CML Micro
-
SGTL5000XNLA3
NXP Semiconductors
-
TLV320AIC3104IRHBR
Texas Instruments
-
MAX9867EWV+T
Analog Devices Inc./Maxim Integrated
-
MAX9860ETG+T
Analog Devices Inc./Maxim Integrated
-
TLV320AIC3106IRGZR
Texas Instruments
-
SGTL5000XNLA3R2
NXP Semiconductors
Tech Hub
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…
Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…
Jumper cables guide covering safe connection order, red and black clamp placement, final ground connection, cable gauge, length, clamp quality, copper vs CCA cables, jump starter comparison and battery…
