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NXP Semiconductors MC34845AEPR2
- Part No.:
- MC34845AEPR2
- Manufacturer:
- NXP Semiconductors
- Category:
- LED Drivers
- Package:
- 24-UFQFN Exposed Pad
- Datasheet:
-
MC34845AEPR2.pdf
- Description:
- IC LED DRVR RGLTR PWM 2.3A 24QFN
- Quantity:
- Payment:
- Shipping:
Inventory:3,692
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Product details
Overview
MC34845AEPR2 from NXP Semiconductors is a six-channel LED backlight driver IC 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 (3–30 mA per channel), and features dynamic headroom control, PWM dimming, and comprehensive fault protection including LED open/short, overtemperature, overcurrent, and overvoltage.
For engineers reviewing the MC34845AEPR2 datasheet, MC34845AEPR2 pinout, MC34845AEPR2 application, or MC34845AEPR2 equivalent, this device is selected for mid-size portable display power management where high channel-to-channel current accuracy, integrated power conversion, and single-wire wake-up capability are required in space-constrained QFN-EP layouts.
Technical Context
The MC34845AEPR2 implements a current-mode boost converter with fixed 600 kHz switching frequency (per Table 1: MC34845CEP variant), dynamic headroom control (DHC) that auto-adjusts VOUT based on LED string voltage, and external compensation via COMP pin using type-II network. Its six independent current-sink channels use matched internal current mirrors for ≤±2% tolerance at 10–30 mA.
Fault handling includes cycle-by-cycle overcurrent limiting (2.1 A typical IBOOST_LIMIT), internally fixed 60 V OVP (typical), programmable external OVP via resistor divider (15–60 V range), and dedicated FAIL open-drain fault indicator. Low-power operation is enabled via EN pin or single-wire WAKE/PWM scheme with 27–33 ms shutdown 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 batteries or 12 V rail without pre-regulation. |
| Boost Output Voltage | Up to 60 V - sufficient to drive up to 16-series LEDs at 3.3 V each (52.8 V) with margin for diode drop and ripple. |
| Integrated Boost FET | 2.0 A rated - supports ≥10 W total LED power (6 × 30 mA × 55 V ≈ 9.9 W) with thermal derating. |
| LED Current Accuracy | ±2% max channel-to-channel mismatch - ensures uniform brightness across multi-string edge-lit LCD backlights. |
| Switching Frequency | 600 kHz (MC34845C variant) - enables compact magnetics (e.g., 22–33 µH inductors) and reduces audible noise vs. 300 kHz alternatives. |
| OVP Protection | Internally fixed 60 V (typical) + externally programmable down to 15 V - dual-layer safeguard against boost overvoltage failure modes. |
| Thermal Resistance | Junction-to-case 3.1 °C/W - requires exposed pad (EP) soldering to PCB copper for reliable operation at full load. |
Pinout & Package
MC34845AEPR2 is housed in a 24-pin QFN-EP (exposed pad) package (outline 98ASA00602D), measuring 4 mm × 4 mm × 0.85 mm, with thermal pad tied to GND for heat dissipation. Pin 1 is VIN; pins 2/5 are PGNDB/PGNDA (boost FET grounds); pins 3/4 are SWB/SWA (boost switch nodes); pins 7–12 are CH1–CH6 (LED sink outputs); EP is ground-connected thermal pad.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN (Pin 1) | Main supply input | Accepts 5–21 V; powers internal LDOs (VDC1/VDC2) and boost controller; UVLO threshold 4.0–4.4 V. |
| CH1–CH6 (Pins 7–12) | LED current sinks | Each drives up to 30 mA; channel-to-channel current match ≤±2%; minimum regulated voltage 0.75 V (typ). |
| ISET (Pin 15) | Current reference input | Resistor-to-GND sets LED current via RSET = 153 / ILED; 0.1% resistor recommended for best accuracy. |
| PWM (Pin 16) | Digital dimming control | Direct PWM input (0.4–100 kHz); modulates LED current linearly; 10%–100% duty yields 10%–100% ILED. |
| EN (Pin 6) | Enable control | Active-high logic; internal pull-down; pulls supply current to ≤10 μA in shutdown mode. |
| WAKE (Pin 18) | Single-wire low-power entry | When tied to PWM and EN grounded, holds device in shutdown until PWM low time exceeds 27–33 ms. |
| FAIL (Pin 14) | Fault indicator | Open-drain output; low-impedance when no fault; high-impedance during LED open/short, OCP, OTP, or OVP events. |
| OVP (Pin 22) | External overvoltage sense | Resistor divider from VOUT to GND programs OVP threshold (15–60 V); internal 60 V OVP acts as backup. |
| COMP (Pin 17) | Boost loop compensation | Connects external RC network (e.g., 33 nF + 220 pF + 2 kΩ) to stabilize current-mode boost control loop. |
| SWA/SWB (Pins 4/3) | Boost switch nodes | Internal FET drain connections; require low-ESR ceramic output capacitor and Schottky flyback diode. |
| GND (Pins 13,19,21) | Analog/digital reference | Signal ground for control circuitry; separate from PGNDA/PGNDB (power ground for boost FET). |
| EP | Thermal pad | Must be soldered to PCB ground plane; contributes to 3.1 °C/W θJC and overall thermal reliability. |
Key Features
| Feature | Design Value |
|---|---|
| Dynamic Headroom Control (DHC) | Automatically adjusts VOUT to minimum required voltage above LED string forward voltage - reduces power loss and heat generation. |
| Six Independent Current Sinks | Each CHx pin delivers precisely matched current (±2% max) without external sensing resistors - simplifies layout and improves display uniformity. |
| Integrated 2.0 A Boost FET | Eliminates need for external MOSFET and gate driver - reduces BOM count, board area, and EMI sources in portable backlight designs. |
| Programmable Overvoltage Protection | OVP threshold set via external resistor divider (15–60 V range) with internal 60 V backup - prevents catastrophic failure during LED string open-circuit events. |
| Single-Wire Wake-Up Mode | WAKE + PWM tie-off enables ultra-low standby current (<10 μA) without additional control lines - ideal for battery-powered netbooks and GPS devices. |
| Comprehensive Fault Detection | Detects and reports LED open/short, boost overcurrent (10 ms timeout), overtemperature (150 °C shutdown), and input UVLO - enables robust system-level error recovery. |
Applications
| PC Notebook Backlight | Industrial Display Backlight |
|---|---|
Use Scenario: Driving six parallel LED strings in a 15.6" edge-lit notebook LCD panel powered by 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 to 20 mA with ±2% matching; manages VOUT dynamically via DHC. Use Value: Enables thin (<2.5 mm) mechanical profile, extends battery runtime via >90% peak boost efficiency, and eliminates brightness non-uniformity across display edges. | Use Scenario: Backlighting a ruggedized 12.1" industrial HMI display operating in -40°C to 85°C ambient with 24 V DC input. IC Role / Device Role / Timing Role: Six-channel constant-current driver with integrated 600 kHz boost; handles wide input (5–21 V) and provides fail-safe OVP/OTP/LED fault reporting via FAIL pin. Use Value: Reduces component count vs. discrete boost + current source solutions; ensures long-term reliability under thermal stress via 150 °C shutdown and 3.1 °C/W θJC. |
| Portable DVD Player Display | Healthcare Device Screen |
Use Scenario: Powering 10" LCD backlight in consumer portable DVD player using 2-cell Li-ion (7.4 V nominal) with PWM dimming controlled by microcontroller. IC Role / Device Role / Timing Role: LED driver with direct PWM interface (600 Hz–100 kHz); supports 3–30 mA per channel; uses WAKE/PWM single-wire mode for <10 μA standby. Use Value: Achieves >8-hour playback via low quiescent current and high-efficiency boost; eliminates flicker with linear PWM dimming response. | Use Scenario: Backlighting a 7" medical tablet display requiring Class II safety isolation, stable luminance, and fault logging for regulatory compliance. IC Role / Device Role / Timing Role: Six-channel current sink with open/short LED detection and FAIL pin assertion; operates from isolated 12 V supply; supports programmable OVP for safety margin. Use Value: Provides real-time fault visibility for diagnostic logging; maintains display brightness consistency critical for clinical image interpretation. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar LED backlight driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MC34844DEPR2 | 300 kHz boost frequency, lower IBOOST_LIMIT (2.1–2.6 A), different slope compensation (0.22 V/μs) | Better suited for higher-inductance, lower-RMS-current designs; slightly lower efficiency at light loads due to lower fSW | Select when thermal constraints favor lower switching losses or when 300 kHz EMI profile is required. |
| TPS61165DRVR | Single-channel, 40 V max boost, no integrated OVP programming, no FAIL pin, 1.2 A FET | Lacks multi-string current matching and comprehensive fault reporting; requires external current sensing for multi-LED arrays | Choose only for simple single-string applications where cost and size outweigh channel matching and safety features. |
Compared with MC34845AEPR2, MC34844DEPR2 offers lower-frequency operation for reduced EMI but sacrifices some efficiency and channel count flexibility, while TPS61165DRVR lacks integrated multi-channel control and fault diagnostics-making it unsuitable as a drop-in replacement for six-string backlight systems.
Availability
MC34845AEPR2 is available at Aetrix Electronics and suitable for PC notebooks, industrial HMIs, and portable media players requiring stable component supply, long-lifecycle support, and automotive-grade reliability in compact QFN packages.
Supply support for MC34845AEPR2 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 MC34845AEPR2 belongs to NXP's SMARTMOS-based LED backlight driver product line, engineered specifically for energy-efficient, high-accuracy LCD backlighting in portable and industrial displays from 10" to 17".
FAQ
What is the maximum LED string voltage supported by the MC34845AEPR2?
The MC34845AEPR2 supports a maximum boost output voltage of 60 V (typical), with an internally fixed overvoltage protection threshold at 60 V. When using external OVP programming, the upper limit remains 60 V, and the minimum programmable level is 15 V. This allows driving up to 16 white LEDs (3.3 V VF each) plus margin for diode drop and ripple, making MC34845AEPR2 suitable for 10–17" edge-lit LCD panels.
How does the Dynamic Headroom Control (DHC) function in the MC34845AEPR2?
The Dynamic Headroom Control in MC34845AEPR2 continuously monitors LED string voltage via feedback and adjusts the boost converter's output voltage to the minimum level required-typically 0.5–1.5 V above the total forward voltage of the active LED string. This minimizes power dissipation in the current sinks and improves overall system efficiency, especially at partial brightness levels where VOUT would otherwise remain fixed at maximum.
Can the MC34845AEPR2 operate in single-wire wake-up mode without an external enable signal?
Yes, the MC34845AEPR2 supports single-wire wake-up mode: connect the WAKE and PWM pins together and tie EN to GND. In this configuration, holding PWM low for longer than 27–33 ms places MC34845AEPR2 into shutdown (<10 μA supply current), while a high PWM pulse wakes it immediately. This eliminates the need for a dedicated EN control line in space-constrained portable designs.
What is the recommended external compensation network for the MC34845AEPR2 boost converter?
The MC34845AEPR2 requires a Type II compensation network on the COMP pin. For the 600 kHz variant, NXP recommends RCOMP = 2.0 kΩ, CCOMP1 = 33 nF, and CCOMP2 = 220 pF. A resistor divider from PWM to COMP (e.g., 3.3 kΩ + 10 kΩ) can inject 1.0 V to improve transient response. Layout must place these components close to the MC34845AEPR2 with short traces to ensure loop stability.
Does the MC34845AEPR2 provide channel-to-channel current matching, and how is it achieved?
Yes, the MC34845AEPR2 guarantees ≤±2% LED current matching across all six channels (CH1–CH6) for currents between 10 mA and 30 mA. This is achieved through precision-matched internal current mirror circuitry and laser-trimmed references-no external sensing resistors are needed. The matching accuracy degrades slightly to ±4% at 3–10 mA, as confirmed in Table 4's ITOLERANCE specification.
MC34845AEPR2 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- NXP Semiconductors
- Series:
- -
- Package/Case:
- 24-UFQFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- 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:
- 1.2MHz
- Dimming:
- PWM
- Applications:
- Backlight
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 24-QFN-EP (4x4)
MC34845AEPR2 FAQ
1.How can I place an order for MC34845AEPR2 through Aetrix?
Please submit a Request for Quotation (RFQ) for MC34845AEPR2 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 MC34845AEPR2 reliable?
The price and inventory of MC34845AEPR2 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MC34845AEPR2 is usually 5 days.
3.What payment methods are accepted for MC34845AEPR2?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MC34845AEPR2 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MC34845AEPR2?
MC34845AEPR2 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MC34845AEPR2 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 MC34845AEPR2?
For technical support, including MC34845AEPR2 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MC34845AEPR2 requirements.
6.How does Aetrix verify that MC34845AEPR2 is sourced from the original manufacturer or authorized distributors?
All MC34845AEPR2 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 MC34845AEPR2 meets industry standards.
7.What is the process for return or replacement of MC34845AEPR2?
All MC34845AEPR2 units undergo pre-shipment inspection (PSI). If there is an issue with MC34845AEPR2, 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 MC34845AEPR2 part is unused and in its original packaging.
Return procedure for MC34845AEPR2:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
MC34845AEPR2 Tags
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