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NXP Semiconductors MC34845EP
- Part No.:
- MC34845EP
- Manufacturer:
- NXP Semiconductors
- Category:
- LED Drivers
- Package:
- 24-UFQFN Exposed Pad
- Datasheet:
-
MC34845EP.pdf
- Description:
- IC LED DRVR RGLTR PWM 2.3A 24QFN
- Quantity:
- Payment:
- Shipping:
Inventory:3,948
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Product details
Overview
MC34845EP 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 six strings (3–30 mA per channel), and features programmable OVP, thermal shutdown, and LED open/short protection. It targets edge-lit notebook and portable display backlighting.
For engineers reviewing the MC34845EP datasheet, MC34845EP pinout, MC34845EP application, or MC34845EP equivalent, key selection considerations include its 24-pin QFN-EP package, fixed 300 kHz boost frequency (per EP suffix), dynamic headroom control, PWM dimming interface, and fault reporting via open-drain FAIL pin.
Technical Context
The MC34845EP implements a current-mode boost converter with Dynamic Headroom Control (DHC) that automatically adjusts VOUT to match LED string voltage requirements-only active for LED pulse widths >400 ns. Its internal 2.0 A SMARTMOS FET, external compensation on COMP pin, and fixed 300 kHz switching frequency (confirmed for MC34845DEP variant) define its power stage behavior.
As a six-channel constant-current sink driver, it uses a single ISET resistor to set all channels identically (RSET = 153 / ILED), achieving ≤±2% channel-to-channel current tolerance at 10–30 mA. Fault detection includes LED open (OFDV = 0.55 V), short (SFDV = 7.0 V), overtemperature (150 °C shutdown), and boost overcurrent (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 regulation. |
| Boost Output Voltage | Up to 60 V - sufficient for 14+ series LEDs at 30 mA (e.g., 14 × 2.8 V ≈ 39 V + headroom). |
| LED Current Range | 3.0 mA to 30 mA per channel - set by single ISET resistor; 0.1% tolerance recommended. |
| Channel Matching | ±2% max tolerance - ensures uniform brightness across six independent LED strings. |
| Switching Frequency | 300 kHz (typical) - fixed for MC34845DEP; enables compact magnetics and low EMI in portable designs. |
| OVP Threshold | Internally fixed 60 V (typ) - failsafe backup if external OVP divider opens; externally programmable down to 15 V. |
| Fault Protection | LED open/short, overtemperature (150 °C), overcurrent (cycle-by-cycle + 10 ms timeout), UVLO - reduces system-level safety circuitry. |
Pinout & Package
MC34845EP is housed in a thermally enhanced 24-pin QFN-EP (exposed pad) package (outline 98ASA00602D), measuring 4 mm × 4 mm × 0.85 mm, with 0.5 mm pitch and JEDEC-standard wettable flanks for automated optical inspection.
| 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; has 4.0–4.4 V UVLO with hysteresis. |
| SWA/SWB (Pins 3,4) | Boost switch nodes | Connect to external boost inductor and Schottky diode; SWA/SWB share internal 2.0 A FET; RDS(on) = 300–520 mΩ. |
| CH1–CH6 (Pins 7–12) | LED current sinks | Each drives one LED string up to 30 mA; off-state leakage <1.0 μA at 45 V; min on-voltage = 0.675 V. |
| ISET (Pin 15) | Current reference input | Resistor to GND sets all six channels; VISET = 2.043 V (typ); RSET = 153 / ILED (kΩ for mA). |
| PWM (Pin 16) | Digital dimming control | Direct PWM input (0.5 V low / 1.5 V high); controls LED current linearly from 10% to 100% duty cycle at up to 100 kHz. |
| FAIL (Pin 14) | Open-drain fault indicator | Pulled low during normal operation; goes high-Z on any fault (LED open/short, OCP, OTP); requires EN recycle to clear. |
| EN (Pin 6) | Enable control | Active-high (internal pull-down); asserts shutdown mode drawing only 2.0 μA (typ) when low. |
| WAKE (Pin 18) | Single-wire standby control | Enables low-power mode when tied to PWM and EN grounded; 27–33 ms timeout triggers shutdown on sustained low PWM. |
| OVP (Pin 22) | External overvoltage sense | Accepts resistor divider from VOUT; sets OVP threshold between 15 V and 60 V using 6.9 V internal reference. |
| COMP (Pin 17) | Boost loop compensation | Supports Type II network (e.g., 2 kΩ + 33 nF + 220 pF) for stable current-mode control; slope compensation built-in. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated 2.0 A Boost FET | Eliminates external high-current MOSFET and associated gate drive complexity; RDS(on) optimized for efficiency at 300 kHz. |
| Dynamic Headroom Control (DHC) | Automatically minimizes VOUT to just above required LED string voltage-reducing power loss and heat in boost stage. |
| Six Independent Current Sinks | Enables true multi-zone edge lighting with matched current (±2%)-critical for uniform luminance in notebook displays. |
| Programmable OVP with Internal Backup | External resistor divider sets precise OVP level; internal 60 V clamp prevents catastrophic failure if divider fails open. |
| Single-Wire WAKE Mode | Reduces system GPIO count: PWM signal doubles as enable/disable control when WAKE and EN are configured per datasheet Figure 5. |
Applications
| PC Notebook Backlighting | Portable DVD Player Display |
|---|---|
Use Scenario: Driving 6 parallel LED strings behind a 15.6" edge-lit LCD panel powered from a 3-cell Li-ion battery (9–12.6 V). IC Role / Device Role / Timing Role: MC34845EP acts as the primary LED current controller and boost power supply, regulating each string to 20 mA with ±2% matching. Use Value: Enables thin (<3 mm) mechanical profile, extends battery runtime via DHC efficiency optimization, and simplifies BOM with integrated FET and fault protection. | Use Scenario: Powering a 7" LCD backlight in a consumer portable DVD player using a 12 V wall adapter with variable load conditions. IC Role / Device Role / Timing Role: MC34845EP provides stable 30 mA per string across temperature (-40 to 85 °C), with PWM dimming synchronized to video frame rate. Use Value: Delivers flicker-free dimming down to 1% duty cycle (Figure 9), maintains color consistency via tight current matching, and eliminates need for discrete OVP circuitry. |
| Industrial Panel Display | Healthcare Device Screen |
Use Scenario: Backlighting a ruggedized 12.1" industrial HMI display operating in extended temperature environments with ESD exposure risk. IC Role / Device Role / Timing Role: MC34845EP serves as the fault-resilient LED driver, leveraging its ±2000 V HBM ESD rating, LED open/short detection, and 150 °C thermal shutdown. Use Value: Reduces field failure rate by auto-shutting down on LED string faults and reporting status via FAIL pin to host microcontroller. | Use Scenario: Illuminating a 10.1" medical tablet display requiring consistent brightness, low EMI, and long-term reliability under continuous operation. IC Role / Device Role / Timing Role: MC34845EP functions as the certified-compliant backlight driver, using its fixed 300 kHz switching and ceramic-output-capacitor support to meet CISPR-22 Class B emissions limits. Use Value: Achieves <1% ripple-induced visual artifacts via low-noise 300 kHz operation and integrated soft-start (3.0 ms), critical for diagnostic image clarity. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar LED backlight driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM3409QMH/NOPB | Single-channel buck-boost LED driver; no integrated FET; requires external MOSFET and separate current-sense amplifier. | Lacks multi-string capability and channel matching; suited for single-string high-power LED arrays, not LCD backlighting. | Select only if driving one high-current string (>1 A) where MC34845EP's six-channel architecture is unnecessary. |
| TPS61165DRVR | Single-channel boost LED driver with integrated 1.2 A FET; 1.2 MHz switching; no DHC or multi-string support. | No current matching or multiple outputs; limited to ≤40 V output and 40 mA max per channel. | Choose for cost-sensitive single-string applications below 40 V where board space is constrained but multi-zone control is not required. |
Compared with LM3409QMH/NOPB and TPS61165DRVR, the MC34845EP uniquely integrates six matched current sinks, DHC, and a 2.0 A boost FET in one 4×4 mm QFN-making it the only solution that simultaneously satisfies multi-string uniformity, efficiency optimization, and compactness for mid-size LCD backlighting.
Availability
MC34845EP is available at Aetrix Electronics and suitable for PC notebook backlighting, portable media display systems, and industrial HMI panels requiring stable component supply, automotive-grade reliability, and long-term production continuity.
Supply support for MC34845EP 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 IoT applications, with deep expertise in power management and analog mixed-signal ICs.
The MC34845EP belongs to NXP's SMARTMOS LED backlight driver family, engineered specifically for energy-efficient, fault-tolerant LCD display illumination in portable and industrial equipment demanding high current accuracy and thermal robustness.
FAQ
What is the boost switching frequency of the MC34845EP?
The MC34845EP is the D-version variant, confirmed by its part number suffix "DEP" in Table 1 and datasheet revision history. It operates at a fixed 300 kHz boost switching frequency (min 270 kHz, typ 300 kHz, max 330 kHz), enabling optimized inductor sizing and EMI performance for portable display applications. This differs from the C-version (MC34845CEP) which runs at 600 kHz.
How does the MC34845EP achieve LED current matching across six channels?
The MC34845EP uses a precision current mirror architecture fed by a single ISET reference, delivering ≤±2% channel-to-channel current tolerance at 10–30 mA. This matching is achieved through matched internal transistor geometries and layout symmetry-not external calibration-and is validated over -40°C to 85°C ambient per Table 4's ITOLERANCE specification.
Can the MC34845EP drive more than 16 LEDs in series per string?
No-the MC34845EP's absolute maximum ratings limit CHx pin voltage to 45 V in off-state and 20 V in on-state (Table 3), and its boost output is rated up to 60 V. Assuming typical white LED forward voltage of 3.0–3.3 V, 16 LEDs × 3.3 V = 52.8 V, leaving minimal headroom for dynamic headroom control and ripple. Driving >16 LEDs risks exceeding safe operating area and violating the 45 V off-state CHx rating.
What external components are mandatory for basic MC34845EP operation?
Four components are mandatory: (1) ISET resistor (e.g., 5.1 kΩ for 30 mA), (2) input capacitor (≥10 μF X7R, 25 V), (3) boost inductor (e.g., 33 μH, ISAT ≥ 2.6 A), and (4) output capacitor (e.g., 2 × 4.7 μF X7R, 50 V). Additionally, 2.2 μF capacitors on VDC1 and VDC2 pins are required per datasheet Section 4.2, and the exposed pad (EP) must be soldered to PCB ground for thermal and electrical integrity.
Does the MC34845EP support analog dimming in addition to PWM?
No-the MC34845EP supports only digital PWM dimming via the PWM pin (Section 4.2: PWMCONTROL). It does not implement analog (DC) current adjustment; LED current magnitude is set solely by the ISET resistor, while brightness is controlled exclusively by PWM duty cycle (10–100% range, up to 100 kHz). Attempting analog control on ISET will disrupt regulation and void current matching.
MC34845EP 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)
MC34845EP FAQ
1.How can I place an order for MC34845EP through Aetrix?
Please submit a Request for Quotation (RFQ) for MC34845EP 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 MC34845EP reliable?
The price and inventory of MC34845EP are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MC34845EP is usually 5 days.
3.What payment methods are accepted for MC34845EP?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MC34845EP transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MC34845EP?
MC34845EP orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MC34845EP 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 MC34845EP?
For technical support, including MC34845EP datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MC34845EP requirements.
6.How does Aetrix verify that MC34845EP is sourced from the original manufacturer or authorized distributors?
All MC34845EP 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 MC34845EP meets industry standards.
7.What is the process for return or replacement of MC34845EP?
All MC34845EP units undergo pre-shipment inspection (PSI). If there is an issue with MC34845EP, 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 MC34845EP part is unused and in its original packaging.
Return procedure for MC34845EP:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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