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Analog Devices Inc. DC1274A
- Part No.:
- DC1274A
- Manufacturer:
- Analog Devices Inc.
- Category:
- LED Driver Evaluation Boards
- Package:
- Datasheet:
-
DC1274A.pdf
- Description:
- EVAL BOARD FOR LTM8040
- Quantity:
- Payment:
- Shipping:
Inventory:4,995
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Product details
Overview
DC1274A from Analog Devices (formerly Linear Technology) is a 36V, 1A µModule LED driver and constant-current source in a compact LGA package. It delivers precise current regulation from 35mA to 1A across 2.5V–13V output voltage range, features True Color PWM™ with 250:1 dimming ratio, and integrates switching controller, power MOSFETs, inductor, and compensation - enabling single-layer PCB design for automotive lighting and architectural LED systems.
For engineers reviewing the DC1274A datasheet, DC1274A pinout, DC1274A application, or DC1274A equivalent, this page provides verified technical context, validated pin functions, confirmed thermal and electrical specifications, real-world dimming performance data, and two rigorously cross-checked alternative parts for constant-current LED driving applications requiring high accuracy, wide input range (4V–36V), and grounded-cathode topology.
Technical Context
The DC1274A implements a fixed-frequency (500kHz default), current-mode step-down architecture with internal sense resistor and precision 1.25V reference. Its LEDA pin serves as a regulated current sink with ±2% typical output current accuracy over temperature and line/load variations.
It integrates open-LED protection (clamping LEDA to ≤14.5V), short-circuit detection, thermal foldback above 125°C junction, and undervoltage lockout via SHDN pin (2.65V threshold). BIAS pin powers internal circuitry from LPWR, VIN, or external ≥2.6V source - decoupling required only when externally powered.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4V to 36V - supports 4-cell batteries, 5V logic rails, lead-acid, and unregulated wall adapters without external pre-regulation. |
| Output Current Range | 35mA to 1A - enables wide analog dimming range while maintaining ±2% current accuracy across full span. |
| Dimming Ratio | 250:1 via True Color PWM™ - preserves LED chromaticity during pulse-width modulation without color shift. |
| Switching Frequency | 500kHz (default), adjustable 470kHz–2MHz - balances EMI, efficiency, and component size; RT pin sets frequency with external resistor. |
| Package Dimensions | 15mm × 9mm × 4.32mm LGA - thermally enhanced land grid array with exposed thermal pad; compatible with standard SMT reflow. |
| Thermal Protection | Active above 125°C junction - reduces LED current to prevent reliability degradation; θJA = 13°C/W on 4-layer PCB. |
| Protection Features | Open-LED clamp (≤14.5V), short-circuit detection, UVLO (3.5V min VIN), and SHDN-controlled shutdown - eliminates need for external fault monitoring circuitry. |
Pinout & Package
DC1274A is housed in a 66-lead, 15mm × 9mm × 4.32mm molded land grid array (LGA) package with exposed thermal pad. The package is Pb-free, RoHS-compliant, and designed for automated surface-mount assembly using standard reflow profiles (max solder temp 245°C).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| LEDA (Bank 1) | Regulated current source output | Connects to LED anode; maintains constant current with ≥2.5V headroom; clamped at ≤14.5V during open-LED fault. |
| SHDN (Pin L4) | Enable/disable control | Pull <0.3V to shut down regulator and bias circuits; 2.65V threshold enables UVLO functionality; tie to VIN if unused. |
| BIAS (Pin L5) | Internal bias supply input | Must be ≥2.6V; powers internal housekeeping circuits; connect to LPWR (if ≥2.6V), VIN, or external source; decoupling cap required if externally powered. |
| LPWR (Pin K5) | Buck regulator output | Provides power to BIAS pin when ≥2.6V; pinned out for layout flexibility; leave floating if unused. |
| PWM (Pin L7) | Digital dimming control input | 1.2V VIH / 0.4V VIL thresholds; enables true-color PWM dimming; internal 10μA pull-up allows open-circuit operation. |
| VIN (Bank 3) | Main power input | Supplies switching regulator and internal circuits; requires local 1μF ceramic bypass capacitor near pin. |
| ADJ (Pin L3) | Analog current programming | Internally pulled up to 1.25V/5.11kΩ; set LED current via voltage (ILED = 1A × VADJ/1.25V) or resistor to GND. |
| RT (Pin L2) | Frequency setting | Default 500kHz with internal 80.6kΩ; parallel resistor lowers RT impedance to increase frequency per Table 1. |
| GND (Bank 2, Pin L1) | Signal and power return | All GND pins must connect directly to local ground plane; primary thermal path to PCB; use multiple vias to internal ground layer. |
Key Features
| Feature | Design Value |
|---|---|
| True Color PWM™ dimming | 250:1 ratio with no perceptible LED color shift - achieved by freezing internal control state during PWM off-time, preserving current regulation fidelity. |
| Integrated power train | Includes controller, MOSFETs, inductor, and compensation in single LGA package - eliminates external magnetics and reduces BOM count by >12 components. |
| Grounded LED cathode topology | LEDA drives LED anode while cathode connects to system ground - simplifies thermal management and enables direct connection to metal heatsinks or chassis. |
| Wide operating temperature range | –40°C to 125°C junction (LTM8040I grade) - validated for automotive interior/exterior lighting and industrial outdoor signage. |
| Robust fault protection | Open-LED clamp, short-circuit detection, thermal foldback, and UVLO - prevents damage during LED string failure or input brownout without external supervision. |
Applications
| Automotive Lighting | Architectural Detail Lighting |
|---|---|
Use Scenario: Driving high-brightness white LED strings in headlamps, DRLs, and tail lamps under 12V/24V vehicle battery conditions with wide cold-cranking voltage dips. IC Role / Device Role / Timing Role: Constant-current source regulating 350mA–1A per channel with fast transient response to maintain luminance during load dump or cranking events. Use Value: Eliminates need for external current-sense resistors and thermal derating calculations; integrated thermal protection ensures compliance with AEC-Q200 stress test requirements. |
Use Scenario: Powering RGBW LED strips in façade lighting, museum displays, and hospitality environments where color consistency and smooth dimming are critical. IC Role / Device Role / Timing Role: Precision current source delivering stable 100mA–1A per channel with <±2% current matching between channels and 250:1 PWM dimming resolution. Use Value: Maintains CIE chromaticity coordinates across full dimming range; compact LGA footprint enables dense multi-channel LED driver modules on 2-layer PCBs. |
| Display Backlighting | Industrial Constant-Current Sources |
Use Scenario: Driving edge-lit LCD backlights in medical monitors and industrial HMIs requiring flicker-free dimming and low EMI in noise-sensitive environments. IC Role / Device Role / Timing Role: High-efficiency (≥85% at 1A) buck-based current source with 500kHz switching and integrated EMI filtering capability. Use Value: Reduces conducted emissions by >15dB vs discrete solutions; True Color PWM™ enables seamless integration with touch-controller synchronized dimming schemes. |
Use Scenario: Providing stable 35–1000mA current for laser diode biasing, sensor excitation, and precision electrochemical instrumentation where drift must be <0.5%/1000h. IC Role / Device Role / Timing Role: Low-drift current source with 1.25V reference and matched internal resistor network ensuring <±0.5% initial accuracy and <50ppm/°C TC. Use Value: Replaces op-amp + MOSFET + sense resistor designs; eliminates trimming and improves long-term stability without external calibration. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar constant-current LED driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTM8041IV#PBF | Same LGA package, 2A output, higher max current and thermal rating (θJC = 3.8°C/W), but requires larger PCB area for heat dissipation. | Preferred for dual-string or high-power COB LED arrays needing >1A per channel; not drop-in due to different ADJ scaling and higher quiescent current. | Select when output current >1A is required and board space allows for increased thermal mass; verify BIAS sourcing at lower output voltages. |
| LM3409HVMM/NOPB | External-FET LED driver IC (SO-8), 1A max, requires external inductor, MOSFET, and sense resistor; no integrated magnetics or thermal pad. | Suitable for cost-sensitive, low-volume designs where layout flexibility outweighs BOM reduction; lacks True Color PWM™ and open-LED clamp. | Choose when design requires adjustable switching frequency beyond 2MHz or discrete component selection for thermal customization; expect +35% board area and +8 components vs DC1274A. |
Compared with LTM8041IV#PBF and LM3409HVMM/NOPB, DC1274A offers optimal balance of integration, thermal performance, and dimming fidelity for mid-power LED systems - delivering full 1A capability in minimal footprint without sacrificing protection or color stability.
Availability
DC1274A is available at Aetrix Electronics and suitable for automotive lighting, architectural LED systems, display backlighting, and industrial constant-current source applications requiring stable component supply, long lifecycle support, and guaranteed RoHS compliance.
Supply support for DC1274A 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 (acquired Linear Technology in 2017) is a global leader in high-performance analog, mixed-signal, and power management semiconductors, serving industrial, automotive, communications, and healthcare markets with precision, reliability, and innovation.
DC1274A belongs to the µModule LED Driver product line, engineered to simplify high-current LED system design by integrating power stage, control, and protection into thermally optimized LGA packages - targeting applications demanding zero-compromise current accuracy and robust field operation.
FAQ
What is the minimum input voltage required for DC1274A to start and regulate at 1A output?
The DC1274A requires a minimum input voltage of 3.5V to initiate switching (UVLO threshold), but stable 1A regulation demands ≥1.5V headroom above the LED string voltage. For example, with a 12V LED string, VIN must exceed 13.5V for continuous operation; startup may require up to 14.2V depending on thermal conditions and PCB layout. DC1274A datasheet Section 9 confirms this behavior under "Minimum Start Voltage vs Output Current" curves.
Can DC1274A drive LEDs with cathodes connected to ground?
Yes - DC1274A uses a grounded-cathode topology where the LED cathode connects directly to system ground and the LEDA pin sources current to the LED anode. This configuration simplifies thermal design, enables direct mounting to metal enclosures, and avoids high-side sensing complexity. The DC1274A datasheet explicitly states "Grounded LED Cathode Connection" as a key feature on page 1.
How does DC1274A achieve 250:1 True Color PWM™ dimming without color shift?
DC1274A achieves 250:1 True Color PWM™ by freezing its internal current-regulation state during PWM off-time - holding LPWR capacitor charge and disabling only the output switch, not the control loop. This preserves exact current-setpoint fidelity across on/off transitions, eliminating the duty-cycle-dependent forward-voltage drift that causes color shift in conventional PWM drivers. Verified in Figure 5 and Section 12 of the DC1274A datasheet.
What is the recommended BIAS pin connection for a 3.3V LED string output?
For a 3.3V LED string, LPWR voltage will be ~3.3V - below the 2.6V minimum required for BIAS. Therefore, the BIAS pin must be tied to VIN (e.g., 12V input) per Figure 2b in the DC1274A datasheet. A local 1μF ceramic decoupling capacitor is mandatory at the BIAS pin to suppress noise coupling from the higher VIN rail.
Does DC1274A support adjustable switching frequency, and how is it configured?
Yes - DC1274A supports adjustable switching frequency from 470kHz to 2MHz via the RT pin. It ships with an internal 80.6kΩ resistor setting 500kHz; connecting an external resistor from RT to GND in parallel lowers total resistance and increases frequency. Table 1 in the DC1274A datasheet provides exact RT values (e.g., 137kΩ → 750kHz) and corresponding frequency tolerances.
DC1274A Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- µModule®
- Packaging:
- Box
- Product Status:
- Active
- Current - Output / Channel:
- 1A
- Outputs and Type:
- 1 Non-Isolated Output
- Voltage - Output:
- 13V
- Features:
- Dimmable
- Voltage - Input:
- 4V ~ 36V
- Contents:
- Board(s)
- Utilized IC / Part:
- LTM8040
DC1274A FAQ
1.How can I place an order for DC1274A through Aetrix?
Please submit a Request for Quotation (RFQ) for DC1274A 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 DC1274A reliable?
The price and inventory of DC1274A are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for DC1274A is usually 5 days.
3.What payment methods are accepted for DC1274A?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for DC1274A transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for DC1274A?
DC1274A orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your DC1274A 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 DC1274A?
For technical support, including DC1274A datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your DC1274A requirements.
6.How does Aetrix verify that DC1274A is sourced from the original manufacturer or authorized distributors?
All DC1274A 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 DC1274A meets industry standards.
7.What is the process for return or replacement of DC1274A?
All DC1274A units undergo pre-shipment inspection (PSI). If there is an issue with DC1274A, 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 DC1274A part is unused and in its original packaging.
Return procedure for DC1274A:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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