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NXP Semiconductors MC34845DEP
- Part No.:
- MC34845DEP
- Manufacturer:
- NXP Semiconductors
- Category:
- LED Drivers
- Package:
- 24-UFQFN Exposed Pad
- Datasheet:
-
MC34845DEP.pdf
- Description:
- IC LED DRVR RGLTR PWM 2.6A 24QFN
- Quantity:
- Payment:
- Shipping:
Inventory:3,603
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Product details
Overview
MC34845DEP from NXP Semiconductors is a six-channel LED backlight driver IC with integrated 2.35 A boost FET, designed for edge-lit LCD displays from 10" to 17". It operates from 5.0 V to 21 V input, delivers up to 60 V boost output, supports 3.0–30 mA per channel with ±2% current matching, and features 300 kHz fixed switching frequency-ideal for notebook and portable display power management.
For engineers reviewing the MC34845DEP datasheet, MC34845DEP pinout, MC34845DEP application, or MC34845DEP equivalent, this page delivers verified technical context, real-world dimming performance data, fault protection behavior, thermal design guidance, and validated alternative options for backlight system integration.
Technical Context
The MC34845DEP implements a current-mode boost converter with Dynamic Headroom Control (DHC) to auto-adjust VOUT based on LED string voltage, requiring ≥400 ns LED drive pulse width for DHC activation. Its internal 2.35 A (typ) boost FET and externally compensated COMP pin support stable operation across varying inductor/capacitor combinations.
It integrates six matched current sinks with ISET-resistor programming, open/short LED detection (OFDV = 0.55 V, SFDV = 7.0 V), overtemperature shutdown at 150 °C, and dual-mode enable: standard EN pin control or single-wire WAKE+PWM low-power entry with 30 ms timeout.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 5.0 V to 21 V - powers directly from 2–3-cell Li-ion or 12 V rail without pre-regulation |
| Boost Output Voltage | Up to 60 V - sufficient for 16-series LED strings at ~3.75 V per LED |
| Boost Switch Current Limit | 2.1 A (min) to 2.6 A (max) - ensures robust startup under high VOUT/low VIN conditions |
| Switching Frequency | 300 kHz (typ) - balances EMI, efficiency, and external component size for portable designs |
| LED Current Accuracy | ±2% max channel-to-channel tolerance - enables uniform brightness across multi-string edge-lit panels |
| OVP Threshold | Internally fixed 60 V (typ); externally programmable down to 15 V - dual-layer protection against LED string failure |
| Thermal Resistance | Junction-to-case 3.1 °C/W - requires direct thermal coupling of EP pad to PCB copper for >1.8 W dissipation at 85 °C ambient |
Pinout & Package
MC34845DEP is housed in a thermally enhanced 24-pin QFN-EP package (98ASA00602D) with exposed thermal pad (EP) tied to GND. The package supports high-power density layout with dedicated PGNDA/PGNDB pins for boost FET return paths and three isolated GND pins (13, 19, 21) for analog/IC ground separation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN (Pin 1) | Main supply input | Accepts 5–21 V; powers internal LDOs and boost FET gate drive; UVLO triggers at 4.0–4.4 V rising |
| SWA/SWB (Pins 4,3) | Boost switch nodes | Connect to external boost inductor and Schottky diode; SWA/SWB share current path but are separate pins for layout symmetry |
| CH1–CH6 (Pins 7–12) | LED current sink outputs | Each drives one LED string up to 30 mA; off-state leakage <1 μA at 45 V; short/open detection active |
| ISET (Pin 15) | Current reference input | Resistor to GND sets LED current via RSET = 153 / ILED; 0.1% resistor recommended for ±2% matching |
| FAIL (Pin 14) | Open-drain fault indicator | Pulled low during normal operation; floats high on LED open, boost OCP, OVP, or overtemperature |
| WAKE (Pin 18) | Single-wire standby control | When tied to PWM and EN grounded, enables automatic shutdown after 30 ms low-PWM duration |
| OVP (Pin 22) | External overvoltage sense | Resistor divider from VOUT to GND programs OVP threshold; internal 60 V OVP remains active as backup |
| COMP (Pin 17) | Boost loop compensation | Accepts Type II network (R+C series + C shunt); recommended values: 2 kΩ, 56 nF, 220 pF for 300 kHz operation |
Key Features
| Feature | Design Value |
|---|---|
| Integrated 2.35 A boost FET | Eliminates external MOSFET and gate driver, reducing BOM count and board area in space-constrained notebooks |
| Dynamic Headroom Control (DHC) | Automatically minimizes VOUT to just above required LED string voltage, improving efficiency by up to 5% vs fixed-output boost |
| ±2% LED current matching | Ensures consistent luminance across all six channels without per-string calibration or trimming |
| Programmable OVP with internal 60 V backup | Prevents catastrophic failure during LED string open-circuit events while allowing flexible design margining |
| Single-wire WAKE+PWM standby mode | Reduces system-level GPIO count and simplifies firmware control for battery-powered portable devices |
Applications
| PC Notebook Backlight | Industrial Display Panel |
|---|---|
Use Scenario: Driving 12–14 LED strings in a 15.6" edge-lit LCD panel powered from a 12 V adapter or 3-cell Li-ion battery. IC Role / Device Role / Timing Role: Primary LED current controller and boost power supply; regulates per-string current and dynamically adjusts VOUT via DHC loop. Use Value: Achieves >90% peak boost efficiency at 35 V output, extends battery runtime, and maintains <2% brightness variation across full viewing angle. |
Use Scenario: Backlighting a ruggedized 12.1" HMI display operating in -40°C to 85°C industrial environment with ESD exposure. IC Role / Device Role / Timing Role: Fault-tolerant LED driver with integrated OCP, OTP, LED open/short detection, and fail-safe FAIL pin reporting. Use Value: Enables unattended operation with automatic channel disable on fault and system-level watchdog reset via FAIL pin monitoring. |
| Portable DVD Player | Healthcare Device Display |
Use Scenario: Powering dual 8-LED strings in a compact 7" portable DVD player using a 2-cell Li-ion pack (6–8.4 V). IC Role / Device Role / Timing Role: High-efficiency boost + current sink IC supporting PWM dimming from 1% to 100% at 25 kHz for flicker-free video playback. Use Value: Delivers linear dimming response with <±2% ILED mismatch across duty cycle, critical for accurate color reproduction in media playback. |
Use Scenario: Illuminating a 10.1" medical tablet display requiring Class I safety isolation and zero-brightness standby compliance. IC Role / Device Role / Timing Role: Low-quiescent-current LED driver (2.0 μA shutdown) with WAKE-enabled instant-on/off and fail-safe black-screen enforcement. Use Value: Meets IEC 60601-1 leakage current limits via EN-controlled hard shutdown and eliminates residual glow during diagnostic mode. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar LED backlight driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MC34845CEP | 600 kHz boost frequency; 2.1 A min boost current limit; no slope compensation (VSLOPE = 0.52 V/μs not applicable) | Better suited for higher-frequency designs needing smaller inductors; less tolerant of high-ESR output capacitors | Select when board space is constrained and 600 kHz EMI filtering is already implemented |
| RT8532GQW | 4-channel, 40 V max boost; 1.5 A FET; no integrated DHC; requires external VREF for current setting | Lacks dynamic headroom control and single-wire WAKE mode; needs additional IC for 6-string support | Consider only for cost-sensitive 4-string applications where DHC and fault coverage are secondary |
Compared with MC34845CEP, MC34845DEP trades higher frequency for lower EMI and better light-load efficiency; compared with RT8532GQW, it provides full 6-channel integration, autonomous VOUT optimization, and comprehensive fault handling in a single die-reducing total solution size by 35% and BOM count by 7 components.
Availability
MC34845DEP is available at Aetrix Electronics and suitable for PC notebook backlighting, industrial HMI displays, and portable media device power management requiring stable component supply, long-term lifecycle support, and automotive-grade reliability validation.
Supply support for MC34845DEP 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
NXP Semiconductors is a global semiconductor leader specializing in secure connectivity solutions for automotive, industrial, and consumer applications, with core expertise in power management and mixed-signal IC design.
The MC34845DEP belongs to NXP's SMARTMOS-based LED backlight driver family, engineered specifically for high-efficiency, low-profile edge-lit LCD backlight systems in portable and industrial displays demanding precise current matching and robust fault resilience.
FAQ
What is the maximum LED string voltage supported by the MC34845DEP?
The MC34845DEP supports up to 60 V boost output voltage, enabling driving of up to 16 LEDs in series (assuming ~3.75 V forward voltage per LED). Its internally fixed OVP threshold is 60 V (typical), and the external OVP can be programmed down to 15 V using a resistor divider on the OVP pin-ensuring safe operation across varied LED configurations in the MC34845DEP application.
How does the Dynamic Headroom Control (DHC) function in the MC34845DEP?
The DHC loop in the MC34845DEP continuously monitors LED string voltage via the CHx pins and dynamically adjusts the boost output (VOUT) to the minimum level required-typically 0.5–1.0 V above the highest string voltage. This occurs only when LED drive pulses exceed 400 ns; shorter pulses disable DHC and default to OVP-limited regulation. This feature directly improves system efficiency in the MC34845DEP design.
Can the MC34845DEP operate in single-wire standby mode without an external enable signal?
Yes-the MC34845DEP supports true single-wire standby via its WAKE pin. By connecting WAKE to PWM and grounding EN, the IC enters low-power shutdown automatically when PWM remains low for >30 ms. Recovery occurs on next PWM high transition. This eliminates need for a dedicated EN control line and reduces MCU GPIO usage in portable MC34845DEP implementations.
What thermal design considerations apply to the MC34845DEP's exposed pad (EP)?
The MC34845DEP's EP pad must be soldered to a minimum 200 mm² copper pour tied to internal GND planes via ≥6 thermal vias (0.3 mm diameter) to achieve the specified 3.1 °C/W junction-to-case thermal resistance. Without proper EP thermal coupling, power dissipation is limited to 1.8 W at 85 °C ambient-critical for sustained 30 mA/channel operation in the MC34845DEP layout.
How is LED current set and trimmed on the MC34845DEP?
LED current in the MC34845DEP is set by a precision resistor (RISET) from ISET (Pin 15) to GND, calculated as RISET = 153 / ILED (kΩ for ILED in mA). For ±2% matching, a 0.1% tolerance resistor is required. VISET remains tightly regulated at 2.043 V (typ), making current setting insensitive to VIN or temperature drift-key for stable brightness in the MC34845DEP system.
MC34845DEP Specifications
- Product attributes
- Attribute value
- Manufacturer:
- NXP Semiconductors
- Series:
- -
- Package/Case:
- 24-UFQFN Exposed Pad
- Packaging:
- Tray
- Product Status:
- Obsolete
- Type:
- DC DC Regulator
- Topology:
- Step-Up (Boost)
- Internal Switch(s):
- Yes
- Number of Outputs:
- 6
- Voltage - Supply (Min):
- 5V
- Voltage - Supply (Max):
- 21V
- Voltage - Output:
- 8V ~ 60V
- Current - Output / Channel:
- 2.6A (Switch)
- Frequency:
- 300kHz
- Dimming:
- PWM
- Applications:
- Backlight
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 24-QFN-EP (4x4)
MC34845DEP FAQ
1.How can I place an order for MC34845DEP through Aetrix?
Please submit a Request for Quotation (RFQ) for MC34845DEP 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 MC34845DEP reliable?
The price and inventory of MC34845DEP are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MC34845DEP is usually 5 days.
3.What payment methods are accepted for MC34845DEP?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MC34845DEP transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MC34845DEP?
MC34845DEP orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MC34845DEP 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 MC34845DEP?
For technical support, including MC34845DEP datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MC34845DEP requirements.
6.How does Aetrix verify that MC34845DEP is sourced from the original manufacturer or authorized distributors?
All MC34845DEP 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 MC34845DEP meets industry standards.
7.What is the process for return or replacement of MC34845DEP?
All MC34845DEP units undergo pre-shipment inspection (PSI). If there is an issue with MC34845DEP, 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 MC34845DEP part is unused and in its original packaging.
Return procedure for MC34845DEP:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
MC34845DEP Tags
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BCR402RE6327HTSA1
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BCR420UE6433HTMA1
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BCR420UE6327HTSA1
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BCR421UE6327HTSA1
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LYT1604D-TL
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HV9910CLG-G
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CL2N8-G
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BCR420UFD-7
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