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NXP Semiconductors MC34845BEP
- Part No.:
- MC34845BEP
- Manufacturer:
- NXP Semiconductors
- Category:
- LED Drivers
- Package:
- 24-UFQFN Exposed Pad
- Datasheet:
-
MC34845BEP.pdf
- Description:
- IC LED DRVR RGLTR PWM 2.6A 24QFN
- Quantity:
- Payment:
- Shipping:
Inventory:4,388
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Product details
Overview
MC34845BEP from NXP Semiconductors is a six-channel LED backlight driver with integrated 2.0 A boost converter, designed for LCD displays from 10" to 17". It operates from 5.0 V to 21 V input, delivers up to 60 V boost output, supports ±2% LED current matching across all six channels, and enables PWM dimming via dedicated PWM pin. It is used in notebook and portable display backlight systems requiring high uniformity and compact power integration.
For engineers reviewing the MC34845BEP datasheet, MC34845BEP pinout, MC34845BEP application, or MC34845BEP equivalent, key selection considerations include its fixed 300 kHz boost frequency (per B-suffix), 24-pin QFN-EP package with exposed thermal pad, programmable LED current (3–30 mA per channel), integrated fault protection (LED open/short, OVP, OTP, OCP), and dynamic headroom control for adaptive VOUT regulation.
Technical Context
The MC34845BEP implements a current-mode boost converter with Dynamic Headroom Control (DHC) that automatically adjusts VOUT to match the forward voltage of up to 16-series LEDs per string while minimizing power loss. Its six independent current sinks use matched internal circuitry to maintain ≤±2% channel-to-channel current tolerance at 3–30 mA.
It features dual shutdown modes: standard EN-active-high enable and single-wire WAKE+PWM low-power mode with 27 ms timeout. Fault detection includes LED open (OFDV = 0.55 V), short (SFDV = 7.0 V typ.), overvoltage (internally fixed 60 V OVP + externally programmable down to 15 V), overtemperature (150 °C shutdown), and cycle-by-cycle overcurrent (2.35 A typ. limit, 10 ms timeout).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 5.0 V to 21 V - supports 2–3 cell Li-ion batteries or 12 V rail without external regulators. |
| Boost Output Voltage | Up to 60 V - sufficient for driving up to 16 white LEDs (3.5 V each) in series per string. |
| Boost Switch Current Limit | 2.35 A (typ.) - sets maximum inductor peak current; limits power delivery during faults or startup. |
| Switching Frequency | 300 kHz (MC34845BEP) - balances efficiency, EMI, and external component size (e.g., 33 µH inductor). |
| LED Current Accuracy | ±2% max channel-to-channel mismatch - ensures consistent brightness across multi-string edge-lit LCD backlights. |
| OVP Threshold | Internally fixed 60 V (typ.) - secondary protection if external resistor divider fails; prevents damage to LED strings or IC. |
| Thermal Resistance | Junction-to-case 3.1 °C/W - requires proper PCB copper area under EP pad for reliable operation at full load. |
Pinout & Package
MC34845BEP is housed in a 24-pin QFN-EP (exposed pad) package (outline 98ASA00602D), measuring 4 mm × 4 mm × 0.85 mm, with thermal pad soldered to PCB ground plane for heat dissipation. Pin 1 is top-left corner (marked), and EP is electrically connected to GND.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN (Pin 1) | Main supply input | Accepts 5–21 V; powers internal LDOs (VDC1/VDC2) and boost FET gate drive; UVLO threshold 4.0–4.4 V. |
| PGNDB / PGNDA (Pins 2, 5) | Power ground for boost FET | Separate low-impedance return path for high-current boost switching; must be routed directly to EP. |
| SWA / SWB (Pins 4, 3) | Boost switch nodes | Connect to external boost inductor and Schottky diode; handle high dv/dt; require tight layout to minimize ringing. |
| EN (Pin 6) | Enable control | Active-high logic input (VIHL ≥ 2.1 V); pulls down internally; asserts shutdown when low. |
| CH1–CH6 (Pins 7–12) | LED current sink outputs | Each drives one LED string; rated for 3–30 mA; off-state leakage <1.0 µA at 45 V. |
| ISET (Pin 15) | Current reference setting | Resistor to GND sets LED current via RSET = 153 / ILED; 0.1% tolerance recommended. |
| PWM (Pin 16) | PWM dimming input | Direct digital dimming control (0–100% duty); supports fPWM up to 100 kHz; min pulse width 0.2 µs in enable mode. |
| WAKE (Pin 18) | Single-wire low-power mode | When tied to PWM and EN grounded, enables automatic shutdown after 27–33 ms low-PWM period. |
| OVP (Pin 22) | External overvoltage sense | Resistor divider from VOUT to GND programs OVP threshold between 15 V and 60 V using 6.9 V internal reference. |
| FAIL (Pin 14) | Fault indicator output | Open-drain; low-impedance when healthy; high-Z on any fault (LED open/short, OVP, OTP, OCP); cleared by EN toggle or POR. |
| COMP (Pin 17) | Boost compensation node | Accepts Type II network (R + C series to GND + shunt C); RCOMP = 2 kΩ typical; stabilizes current-mode loop. |
| VDC1 / VDC2 (Pins 20, 23) | Internal LDO decoupling | VDC1 = 2.5 V (2.2 µF cap), VDC2 = 6.0 V (2.2 µF cap); both for internal use only; not for external loads. |
| GND (Pins 13, 19, 21) | Analog/Logic ground | Reference for control logic, comparators, and bias circuits; separate from PGNDA/B; connects to EP. |
| VOUT (Pin 24) | Boost output feedback | Regulated high-voltage rail; connects to LED anodes and OVP divider; max rating 65 V absolute. |
Key Features
| Feature | Design Value |
|---|---|
| Dynamic Headroom Control (DHC) | Automatically adjusts VOUT to minimum required voltage per LED string, reducing power loss and heat generation in boost stage. |
| Six independent current sinks | Each channel delivers 3–30 mA with ≤±2% matching - eliminates need for external current-setting resistors per string. |
| Integrated 2.0 A boost FET | Eliminates external MOSFET and gate driver; reduces BOM count and board space in compact portable display designs. |
| Programmable OVP with internal backup | External resistor divider sets precise OVP level (15–60 V); internal 60 V fallback prevents catastrophic failure if divider opens. |
| Single-wire WAKE+PWM control | Reduces system GPIO count by combining enable and dimming into one signal - simplifies host MCU interface in space-constrained devices. |
| Comprehensive fault protection | Detects and responds to LED open (0.55 V threshold), short (7.0 V), overtemperature (150 °C), overcurrent (2.35 A), and overvoltage - improves field reliability. |
Applications
| PC Notebook Backlight | Industrial Display Backlight |
|---|---|
Use Scenario: Driving six-edge LED strings in a 15.6" notebook LCD panel powered from a 12 V supply or 3-cell Li-ion battery. IC Role / Device Role / Timing Role: Primary LED current controller and boost power supply; regulates VOUT dynamically and matches current across all strings. Use Value: Enables thin, uniform backlighting with <±2% brightness variation and >90% boost efficiency at 35 V output, extending battery life. | Use Scenario: Backlighting a ruggedized 12" industrial HMI display operating in -40°C to 85°C ambient with ESD-prone environment. IC Role / Device Role / Timing Role: Fault-resilient LED driver with integrated OVP, OTP, and LED open/short detection; provides fail-safe operation in unattended equipment. Use Value: Reduces system-level protection components; FAIL pin alerts host MCU of faults; exposed pad ensures thermal stability at full load. |
| Portable DVD Player | Healthcare Device Display |
Use Scenario: Powering dual 8-LED strings in a clamshell portable DVD player with variable battery voltage (7–12.6 V). IC Role / Device Role / Timing Role: Single-chip solution integrating boost conversion and six-channel current control; supports PWM dimming down to 1% duty cycle. Use Value: Eliminates discrete boost controller + LED drivers; soft-start and slope compensation ensure stable startup across battery range. | Use Scenario: Backlighting a critical-care monitor's 10.1" medical-grade LCD requiring consistent luminance and long-term reliability. IC Role / Device Role / Timing Role: Precision current-matched LED driver with <±2% channel tolerance and programmable OVP to protect against LED degradation over time. Use Value: Ensures display brightness compliance over product lifetime; SMARTMOS process enhances robustness against latch-up and ESD (±2000 V HBM). |
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 | Same architecture but 300 kHz boost frequency (vs. MC34845BEP's 300 kHz); identical pinout and feature set; higher boost current limit (2.35 A vs. 2.1 A typ.). | Optimized for lower EMI and larger inductor values; suitable where 300 kHz is mandated for regulatory compliance or noise sensitivity. | Select MC34845DEP when higher boost current margin or tighter OCP tolerance is needed; verify inductor saturation current ≥2.6 A. |
| LM3409QMHX/NOPB | Single-channel automotive-grade LED controller with external MOSFET; no integrated current sinks or multi-string support; requires external current sensing per channel. | Used in high-reliability automotive clusters; lacks native 6-string matching, DHC, or FAIL pin; needs additional ICs for multi-string operation. | Choose LM3409QMHX/NOPB only for single-string designs requiring AEC-Q100 qualification; not a functional replacement for MC34845BEP's integrated 6-channel capability. |
Compared with MC34845DEP, MC34845BEP offers slightly lower boost current limit but identical timing, protection, and pin compatibility; versus LM3409QMHX/NOPB, MC34845BEP integrates six matched current sinks and boost power stage - reducing component count by >15 parts and eliminating inter-channel calibration.
Availability
MC34845BEP is available at Aetrix Electronics and suitable for PC notebook backlighting, industrial HMI displays, portable media players, and healthcare device displays requiring stable component supply, long lifecycle support, and qualified automotive-grade alternatives.
Supply support for MC34845BEP 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 focused on secure connectivity solutions for automotive, industrial, and IoT applications, with deep expertise in power management and analog mixed-signal ICs.
The MC34845BEP belongs to NXP's SMARTMOS-based LED backlight driver family, engineered specifically for mid-size LCD panels (10"–17") requiring high-efficiency, multi-string current matching, and integrated fault resilience in space-constrained portable electronics.
FAQ
What is the boost switching frequency of the MC34845BEP?
The MC34845BEP has a fixed boost switching frequency of 300 kHz, as indicated by the "B" suffix in its part number. This frequency is factory-trimmed and not user-adjustable. It balances efficiency, electromagnetic interference (EMI) performance, and external component size - enabling use of standard 33 µH inductors and ceramic output capacitors. The datasheet specifies typical frequency range as 270–330 kHz at TA = 25 °C.
How is LED current set on the MC34845BEP?
LED current on the MC34845BEP is set using a precision resistor (0.1% tolerance recommended) connected between the ISET pin (Pin 15) and GND. The relationship is defined by RSET = 153 / ILED, where ILED is the desired current per channel in mA. For example, a 5.1 kΩ resistor sets ~30 mA per channel. The ISET pin voltage remains regulated at ~2.04 V, ensuring stable current programming across temperature and supply variations.
Does the MC34845BEP support single-wire dimming and shutdown control?
Yes, the MC34845BEP supports single-wire control via its WAKE pin (Pin 18). When WAKE is tied to PWM and EN is held low, the device enters low-power shutdown mode automatically if the PWM signal remains low for longer than 27–33 ms. This eliminates the need for a separate enable signal and simplifies host MCU GPIO usage in portable designs - a key feature confirmed in Section 5.2.5 of the MC34845 datasheet.
What fault protections does the MC34845BEP provide?
The MC34845BEP includes LED open detection (OFDV = 0.55 V), LED short detection (SFDV = 7.0 V typ.), overvoltage protection (OVP) with internal 60 V fallback and external programmability, overtemperature shutdown (150 °C), and cycle-by-cycle overcurrent limiting (2.35 A typ.). All faults assert the open-drain FAIL pin (Pin 14) into high-impedance state and can be cleared only by toggling EN or performing a full power-on reset - ensuring robust system-level fault handling.
What package type and thermal characteristics does the MC34845BEP use?
The MC34845BEP uses a 24-pin QFN-EP package (outline 98ASA00602D), 4 mm × 4 mm × 0.85 mm, with an exposed thermal pad (EP) that must be soldered to a PCB ground plane. Its thermal resistance is 3.1 °C/W junction-to-case and 36 °C/W junction-to-ambient (on 2-layer JEDEC board). To maintain safe operation at full load, designers must allocate ≥200 mm² of 2-oz copper under EP and connect it to ≥4 thermal vias to inner ground layers.
MC34845BEP 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)
MC34845BEP FAQ
1.How can I place an order for MC34845BEP through Aetrix?
Please submit a Request for Quotation (RFQ) for MC34845BEP 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 MC34845BEP reliable?
The price and inventory of MC34845BEP are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MC34845BEP is usually 5 days.
3.What payment methods are accepted for MC34845BEP?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MC34845BEP transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MC34845BEP?
MC34845BEP orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MC34845BEP 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 MC34845BEP?
For technical support, including MC34845BEP datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MC34845BEP requirements.
6.How does Aetrix verify that MC34845BEP is sourced from the original manufacturer or authorized distributors?
All MC34845BEP 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 MC34845BEP meets industry standards.
7.What is the process for return or replacement of MC34845BEP?
All MC34845BEP units undergo pre-shipment inspection (PSI). If there is an issue with MC34845BEP, 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 MC34845BEP part is unused and in its original packaging.
Return procedure for MC34845BEP:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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