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NXP Semiconductors MC34845CEP
- Part No.:
- MC34845CEP
- Manufacturer:
- NXP Semiconductors
- Category:
- LED Drivers
- Package:
- 24-UFQFN Exposed Pad
- Datasheet:
-
MC34845CEP.pdf
- Description:
- IC LED DRVR RGLTR PWM 2.3A 24QFN
- Quantity:
- Payment:
- Shipping:
Inventory:3,863
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Product details
Overview
MC34845CEP from NXP Semiconductors is a six-channel LED backlight driver IC with integrated 2.0 A boost converter, 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 programmable OVP, thermal shutdown, and LED open/short protection. It targets notebook and portable display power management.
For engineers reviewing the MC34845CEP datasheet, MC34845CEP pinout, MC34845CEP application, or MC34845CEP equivalent, key selection criteria include its 600 kHz fixed boost frequency, 24-pin QFN-EP package with exposed thermal pad, dynamic headroom control, PWM dimming interface, and fault reporting via open-drain FAIL pin.
Technical Context
The MC34845CEP integrates a current-mode boost controller with Dynamic Headroom Control (DHC) that automatically adjusts VOUT to match LED string voltage requirements above 400 ns pulse width. Its internal 2.0 A SMARTMOS FET, external compensation on COMP pin, and fixed 600 kHz switching frequency (540–660 kHz range) enable stable high-efficiency operation across varying input and load conditions.
It implements six independent current-sink channels with matched accuracy, ISET resistor-based current programming (RSET = 153 / ILED), and comprehensive fault detection-including LED open (OFDV = 0.55 V), short (SFDV = 7.0 V typ), overtemperature (150 °C shutdown), overcurrent (10 ms timeout), and overvoltage (60 V internal OVP).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 5.0 V to 21 V - supports single/dual-cell Li-ion or 12 V rail without pre-regulation |
| Boost Output Voltage | Up to 60 V - sufficient for up to 16-series LEDs at 3.5 V each under worst-case VF drift |
| Boost Switch Current Limit | 1.9 A (min) to 2.3 A (max) - ensures safe operation with margin against peak inductor current |
| Switching Frequency | 540–660 kHz (typ 600 kHz) - enables compact magnetics and low EMI in portable designs |
| LED Channel Current | 3.0 mA to 30 mA (programmable) - set by 0.1% RSET to GND; supports brightness scaling and power optimization |
| Current Matching Tolerance | ±2% (10–30 mA range) - ensures uniform luminance across multi-string edge-lit panels |
| OVP Threshold | Internally fixed 56–64 V (typ 60 V) - failsafe backup if external resistor divider opens |
Pinout & Package
MC34845CEP is housed in a 24-pin QFN-EP (exposed pad) package (outline 98ASA00602D), optimized for thermal dissipation in space-constrained display power modules. The EP pad must be soldered to PCB ground plane for junction-to-ambient thermal resistance of 36 °C/W.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN | Main supply input | Accepts 5–21 V; powers internal LDOs and boost FET gate drive; UVLO threshold 4.0–4.4 V |
| SWA / SWB | Boost switch nodes | Connect to external inductor and Schottky diode; support synchronous rectification topology |
| PGNDA / PGNDB | Power ground (boost FET) | Separate low-impedance return path for boost current; must be routed away from signal GND |
| CH1–CH6 | LED current sinks | Each drives one LED string up to 30 mA; off-state leakage <1.0 μA at 45 V |
| ISET | Current programming reference | 0.1% resistor to GND sets LED current; pin voltage ~2.04 V (typ) at 30 mA |
| PWM | Digital dimming input | Direct PWM modulation (DC–100 kHz); controls all six channels simultaneously with <75 ns rise/fall |
| FAIL | Fault indicator | Open-drain output; pulled low during normal operation; floats high on any detected fault |
| OVP | External overvoltage setting | Resistor divider from VOUT to GND programs OVP level from 15 V to 60 V using 6.9 V internal reference |
| COMP | Boost loop compensation | Accepts Type II network (e.g., 2 kΩ + 33 nF + 220 pF) for stability across load/transient conditions |
| EN / WAKE | Enable & low-power control | EN active-high enables device; WAKE enables single-wire shutdown when tied to PWM and EN grounded |
Key Features
| Feature | Design Value |
|---|---|
| Integrated 2.0 A Boost FET | Eliminates external high-current switch; reduces BOM count and layout area in portable backlight systems |
| Dynamic Headroom Control (DHC) | Automatically minimizes VOUT to just above required LED string voltage, improving efficiency by >5% vs fixed-output boost |
| Six Independent Current Sinks | Enables precise per-string current control for edge-lit uniformity; eliminates need for external current mirrors or DACs |
| Programmable Overvoltage Protection | External resistor divider allows OVP tuning to match exact LED string VF + margin, preventing premature shutdown |
| Comprehensive Fault Detection | Simultaneous monitoring of LED open/short, overtemperature, overcurrent, and overvoltage with FAIL pin assertion |
Applications
| PC Notebook Backlight | Industrial Display Panel |
|---|---|
Use Scenario: Driving 12–16 LED strings in 14" edge-lit notebook LCD with 12 V input and 30 mA/channel current. IC Role / Device Role / Timing Role: Primary LED current controller and boost power supply; manages PWM dimming, thermal safety, and fault reporting. Use Value: Enables thin (<3 mm) bezel design with uniform brightness, 10,000:1 contrast ratio, and battery runtime extension via DHC efficiency gain. | Use Scenario: Powering ruggedized 12.1" industrial HMI display operating continuously at 70 °C ambient. IC Role / Device Role / Timing Role: High-reliability LED driver with overtemperature shutdown (150 °C) and open-drain FAIL signaling to host MCU. Use Value: Ensures uninterrupted operation with automatic fault recovery and traceable failure diagnostics via FAIL pin state. |
| Portable DVD Player | Healthcare Device Display |
Use Scenario: Compact 7" portable DVD player with dual-cell Li-ion (7.4 V) input and 20 mA/channel LED current. IC Role / Device Role / Timing Role: Single-chip solution integrating boost conversion, six-channel current regulation, and low-power wake mode. Use Value: Reduces component count by 40% vs discrete boost + current sink solutions; extends playback time via 90% peak boost efficiency. | Use Scenario: Medical-grade patient monitor display requiring Class I safety isolation and consistent luminance over 10-year service life. IC Role / Device Role / Timing Role: Precision current-matched LED driver with ±2% channel tolerance and fail-safe OVP to prevent LED overvoltage stress. Use Value: Guarantees diagnostic image fidelity and compliance with IEC 60601-1 leakage current limits via robust internal grounding architecture. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar LED backlight driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MC34845DEP | 300 kHz boost frequency (vs 600 kHz); higher boost current limit (2.1–2.6 A); includes slope compensation (0.22 V/μs) | Better suited for lower EMI environments and higher-current strings (>25 mA); requires different compensation network | Select MC34845DEP when lower switching noise or higher peak LED current is prioritized over compact inductor size. |
| TPS61165DRVR | Single-channel, 40 V max boost, 1.2 A FET, no integrated current matching; requires external current sources | Lacks multi-string integration; used where only one LED string is needed or where discrete current control is preferred | Choose TPS61165DRVR only for single-string designs or when system-level current matching is handled externally. |
Compared with MC34845CEP, MC34845DEP offers higher current capability and lower EMI at the cost of larger magnetics, while TPS61165DRVR provides flexibility in single-string applications but increases design complexity and component count for multi-string use.
Availability
MC34845CEP is available at Aetrix Electronics and suitable for PC notebook backlighting, industrial display panels, and portable media player designs requiring stable component supply, long-term lifecycle support, and automotive-grade reliability validation.
Supply support for MC34845CEP 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 analog mixed-signal ICs.
The MC34845CEP belongs to NXP's SMARTMOS LED backlight driver family, engineered specifically for high-efficiency, multi-string LCD backlighting in portable and mid-size displays with stringent thermal and reliability requirements.
FAQ
What is the maximum LED string voltage supported by the MC34845CEP?
The MC34845CEP supports a maximum boost output voltage of 60 V (typical), which corresponds to the internally fixed overvoltage protection threshold. When using external OVP programming, the upper limit remains 60 V, and the minimum programmable OVP level is 15 V. This allows driving up to 16 white LEDs (3.5 V typical VF) in series with margin for temperature and aging drift. The MC34845CEP must be configured with appropriate external components-especially the OVP resistor divider-to avoid premature shutdown under nominal operating conditions.
How does the Dynamic Headroom Control (DHC) function in the MC34845CEP?
The Dynamic Headroom Control in the MC34845CEP continuously monitors LED string voltage via the VOUT feedback and adjusts the boost converter output to maintain minimal headroom-just enough to sustain conduction across all six channels. It operates only when LED driver pulse widths exceed 400 ns; below this, the DHC circuit is inactive and VOUT defaults to the programmed OVP level. This feature improves system efficiency by reducing switching losses and heat generation, especially at partial brightness levels. The MC34845CEP implements DHC without requiring external sensors or host MCU intervention.
Can the MC34845CEP drive more than six LED strings?
No, the MC34845CEP is strictly a six-channel LED driver with dedicated CH1–CH6 pins; it cannot drive more than six independent LED strings. Each channel is a matched current sink with ±2% tolerance between channels, and all six are controlled simultaneously by the single PWM input. To drive additional strings, multiple MC34845CEP devices must be synchronized using shared PWM and EN signals, with careful attention to timing skew and thermal management. The MC34845CEP does not support daisy-chaining or master-slave configuration in its datasheet-defined operation.
What is the role of the COMP pin on the MC34845CEP, and what external components are required?
The COMP pin on the MC34845CEP is the compensation node for the boost converter's current-mode control loop. It requires an external Type II compensation network-typically a series RC (e.g., 2 kΩ + 33 nF) with a shunt capacitor (e.g., 220 pF) to ground-to ensure loop stability across line, load, and temperature variations. NXP recommends CCOMP1 = 33 nF and CCOMP2 = 220 pF for standard 600 kHz operation. Incorrect or missing compensation can cause VOUT oscillation, poor transient response, or startup failure. The MC34845CEP datasheet provides detailed design equations and layout guidance for the COMP network.
Does the MC34845CEP support analog dimming in addition to PWM dimming?
No, the MC34845CEP supports only digital PWM dimming via the dedicated PWM pin; it does not implement analog (DC) dimming through ISET or other pins. LED current is set exclusively by the ISET resistor and remains constant during active periods; brightness is controlled solely by modulating the duty cycle of the PWM signal (DC to 100 kHz). Attempting to vary ISET voltage dynamically will not produce linear dimming and may violate specification limits. For applications requiring smooth analog dimming, an external DAC-controlled current source or a different driver IC must be used alongside the MC34845CEP.
MC34845CEP 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:
- 2.3A (Switch)
- Frequency:
- 600kHz
- Dimming:
- PWM
- Applications:
- Backlight
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 24-QFN-EP (4x4)
MC34845CEP FAQ
1.How can I place an order for MC34845CEP through Aetrix?
Please submit a Request for Quotation (RFQ) for MC34845CEP 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 MC34845CEP reliable?
The price and inventory of MC34845CEP are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MC34845CEP is usually 5 days.
3.What payment methods are accepted for MC34845CEP?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MC34845CEP transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MC34845CEP?
MC34845CEP orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MC34845CEP 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 MC34845CEP?
For technical support, including MC34845CEP datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MC34845CEP requirements.
6.How does Aetrix verify that MC34845CEP is sourced from the original manufacturer or authorized distributors?
All MC34845CEP 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 MC34845CEP meets industry standards.
7.What is the process for return or replacement of MC34845CEP?
All MC34845CEP units undergo pre-shipment inspection (PSI). If there is an issue with MC34845CEP, 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 MC34845CEP part is unused and in its original packaging.
Return procedure for MC34845CEP:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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