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Allegro MicroSystems A8434EESTR-T
- Part No.:
- A8434EESTR-T
- Manufacturer:
- Allegro MicroSystems
- Category:
- LED Drivers
- Package:
- 16-WFQFN Exposed Pad
- Datasheet:
-
A8434EESTR-T.pdf
- Description:
- IC LED DRV RGLTR MULT-STEP 16QFN
- Quantity:
- Payment:
- Shipping:
Inventory:4,930
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Product details
Overview
A8434EESTR-T from Allegro MicroSystems is a 6-channel high-efficiency fractional charge pump white LED driver IC designed for portable display backlighting. It delivers up to 30 mA per channel across six WLEDs with 0.5% typical current matching, operates from 2.7–5.5 V input, supports adaptive 1×/1.5×/2× voltage multiplication, and enables independent single-wire dimming control of main (LED1–LED4) and sub (LED5–LED6) display groups - used in smartphones, digital cameras, and MP3 players.
For engineers reviewing the A8434EESTR-T datasheet, A8434EESTR-T pinout, A8434EESTR-T application, or A8434EESTR-T equivalent, key selection criteria include its 3 × 3 mm QFN/MLP-16 ES package, dual serial dimming interface timing (tHI/tLO), ISET-based current programming (RSET = 6.49 kΩ → 30 mA), thermal shutdown at 165°C, and guaranteed overvoltage protection up to 6.0 V on VOUT.
Technical Context
The A8434EESTR-T integrates a fractional charge pump with adaptive mode switching (1× → 1.5× → 2×) triggered by LED forward voltage dropout thresholds (Vtrans = 150 mV). Its internal current mirror architecture ensures ±0.5% matching between LED1–LED4 and separately between LED5–LED6, with ILEDx/IISET = 220 A/A ratio fixed by design.
Control is implemented via two dedicated single-wire serial interfaces (ENM and ENS), each supporting 11-step dimming (100% to 5%) and hard reset on >0.5 ms low pulse. The device includes integrated short-circuit detection (VOUT < 1.2 V), open-LED overvoltage protection (trip at 6.0 V), and thermal shutdown with 20°C hysteresis.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 2.7–5.5 V - supports full Li+-battery discharge curve without external regulation. |
| Max Output Current | 30 mA per channel × 6 - sufficient for 6× WLEDs at 3.4 V VF with 20 mA typical drive. |
| Current Matching | ±0.5% (LED1–LED4), ±0.5% (LED5–LED6) - ensures uniform brightness across display segments. |
| Charge Pump Modes | 1×, 1.5×, 2× - automatically selected based on VLEDx dropout; minimizes power loss and EMI. |
| ISET Reference Voltage | 0.6 V - sets LED current via external RSET; ILED = 220 × 0.6 V / RSET. |
| Dimming Interface | Two independent single-wire serial inputs (ENM, ENS) - enables separate main/sub display control without I²C or PWM routing. |
| Thermal Shutdown | 165°C nominal, 20°C hysteresis - protects against sustained overload in compact handheld enclosures. |
| Overvoltage Protection | 6.0 V on VOUT - clamps during open-LED fault, preserving remaining LEDs' operation. |
Pinout & Package
Package: 16-pin QFN/MLP (ES), 3 × 3 mm footprint, 0.75 mm nominal height, exposed thermal pad (EP) tied to GND for thermal performance.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| C2+ | Charge pump capacitor positive terminal | Connects to C2 anode; forms 2× boost stage with C2–; requires 1 µF X5R/X7R ceramic. |
| VOUT | Charge pump regulated output | Supplies anodes of all 6 WLEDs; must be decoupled with 1 µF COUT to GND. |
| ISET | Current reference input | Sinks 40–140 µA; sets LED current via RSET to GND (e.g., 6.49 kΩ → 30 mA). |
| ENS | Sub-display enable/dimming control | Single-wire serial interface for LED5/LED6; 11-step dimming + shutdown on >0.5 ms low pulse. |
| ENM | Main-display enable/dimming control | Single-wire serial interface for LED1–LED4; independent timing and reset from ENS. |
| LED1–LED4 | Main display current sinks | Each sinks up to 30 mA; unused pins must connect to VOUT (never float). |
| LED5–LED6 | Sub-display/flash current sinks | Each sinks up to 30 mA; same bias and disable rules as LED1–LED4. |
| GND | Power and signal ground | Reference for all analog blocks; EP pad must be soldered to PCB ground plane. |
Key Features
| Feature | Design Value |
|---|---|
| Adaptive charge pump mode switching | 1×/1.5×/2× transitions occur automatically at VLEDx = 150 mV dropout, minimizing quiescent loss across battery range. |
| Dual independent dimming interfaces | ENM and ENS support simultaneous or segregated control of main/sub displays without shared timing constraints. |
| 0.5% WLED current matching | Guaranteed matching within main group (LED1–LED4) and sub group (LED5–LED6) enables consistent luminance in segmented displays. |
| Integrated fault protections | Short-circuit (VOUT < 1.2 V), overvoltage (6.0 V), and thermal shutdown (165°C) operate without external components. |
| Low-EMI soft-start | 0.4 ms controlled ramp-up prevents inrush current spikes and reduces conducted EMI during power-on. |
| Thin 3 × 3 mm QFN/MLP-16 package | 0.75 mm height and 3 mm² footprint meet space constraints in ultra-thin mobile devices. |
Applications
| Smartphone Main Display Backlight | Digital Camera Dual-Display System |
|---|---|
Use Scenario: Driving four white LEDs for primary LCD backlight in a 4G/LTE smartphone with Li-ion battery supply. IC Role / Device Role / Timing Role: Charge pump LED driver providing regulated 30 mA per channel with adaptive voltage multiplication to maintain brightness across 4.2 V → 2.7 V battery discharge. Use Value: Eliminates need for inductive boost converter; achieves >85% efficiency at 3.6 V input while meeting tight EMI limits for cellular RF coexistence. |
Use Scenario: Powering four LEDs for main LCD and two additional LEDs for viewfinder OLED sub-display in a compact digital camera. IC Role / Device Role / Timing Role: Dual-group current sink enabling independent brightness control of main and sub displays via ENM/ENS serial pulses. Use Value: Reduces BOM count by replacing two discrete drivers; maintains 0.5% current matching within each group for color-accurate preview and playback. |
| MP3 Player Torch/Flash Mode | Portable Audio Device Sub-Display |
Use Scenario: Using LED5 and LED6 as low-current (≤15 mA) flashlight/torch in a feature-rich MP3 player with limited PCB area. IC Role / Device Role / Timing Role: Secondary current sink group activated via ENS pulses; operates in 1.5× mode at low battery to sustain torch output. Use Value: Enables emergency illumination without dedicated flash IC; leverages existing A8434EESTR-T resources and avoids layout rework. |
Use Scenario: Illuminating a small monochrome status display (e.g., battery level, playback time) alongside main UI in a Bluetooth speaker or DAP. IC Role / Device Role / Timing Role: Sub-display driver operating at reduced current (10–20 mA) with independent dimming via ENS to avoid distracting users during audio playback. Use Value: Provides flicker-free, low-power auxiliary lighting with no additional MCU GPIOs or software overhead. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar white LED driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM3530TMX/NOPB | I²C-controlled 6-channel driver; no adaptive charge pump modes; fixed 1.5×/2× only; requires external I²C host. | Lacks independent single-wire dimming; needs MCU firmware integration instead of hardware-level ENM/ENS pulses. | Choose LM3530TMX/NOPB when system already uses I²C bus and requires dynamic current adjustment per LED. |
| TPS61165DRVR | Inductive boost converter; 30 V max VOUT; supports up to 40 mA per channel; no sub-display grouping. | Higher EMI risk due to inductor; no native dual-group dimming - requires external logic for split control. | Choose TPS61165DRVR when driving higher-VF LEDs (>3.8 V) or needing >30 mA per channel beyond A8434EESTR-T's capability. |
Compared with LM3530TMX/NOPB and TPS61165DRVR, the A8434EESTR-T uniquely combines adaptive fractional charge pumping, dual independent single-wire dimming, and matched 6-channel current sinking in a 3 × 3 mm QFN - making it optimal for space-constrained, battery-powered dual-display systems requiring minimal MCU intervention.
Availability
A8434EESTR-T is available at Aetrix Electronics and suitable for smartphone backlighting, digital camera dual-display systems, and portable audio device sub-display illumination requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.
Supply support for A8434EESTR-T 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
Allegro MicroSystems is a U.S.-based designer and manufacturer of high-performance power ICs and magnetic sensors, serving automotive, industrial, and consumer markets since 1989.
The A8434EESTR-T belongs to Allegro's white LED driver product line, engineered specifically for efficient, low-EMI backlighting in battery-powered portable electronics with segmented or dual-display architectures.
FAQ
What is the maximum LED forward voltage supported by the A8434EESTR-T in 2× mode?
The A8434EESTR-T supports up to 6.0 V on VOUT in 2× mode, enabling use with white LEDs having forward voltages up to ~5.5 V when VIN ≥ 2.7 V. This is validated by the overvoltage protection threshold of 6.0 V and the 2× charge pump equation: VOUT ≈ 2 × VIN − losses. At VIN = 2.7 V, VOUT reaches ~5.0 V before regulation limits apply - sufficient for standard 3.0–3.6 V WLEDs in series configurations.
How does the A8434EESTR-T achieve 0.5% current matching between LED channels?
The A8434EESTR-T achieves ±0.5% current matching through a precision current mirror architecture referenced to the ISET pin's 0.6 V bias. Each LEDx sink replicates the ISET current scaled by a fixed 220× ratio, with laser-trimmed internal resistors and matched transistor geometries minimizing process variation. Matching is separately specified for LED1–LED4 (main group) and LED5–LED6 (sub group), confirmed across –40°C to +85°C ambient.
Can the A8434EESTR-T drive fewer than six LEDs, and how should unused pins be handled?
Yes, the A8434EESTR-T can drive 1–6 LEDs. Unused LEDx pins (e.g., LED5/LED6 in main-only configuration) must be connected to VOUT - never left floating. Leaving them open forces the IC into 2× mode unnecessarily, increasing power loss and noise. Connecting to VOUT ensures the corresponding current sink remains disabled while maintaining correct charge pump mode selection and stability.
What is the minimum pulse width required on ENM or ENS to trigger dimming steps on the A8434EESTR-T?
The A8434EESTR-T requires a minimum high-time pulse width of 0.5 μs (tHI) on ENM or ENS to register a dimming step, with a maximum of 250 μs to avoid misinterpretation as shutdown. Pulses must be separated by ≥0.5 ms (tSHDN) to prevent unintended reset. These values are tested and guaranteed across –40°C to +85°C and ensure reliable 11-step dimming (100% → 5%) without MCU timing margin concerns.
Does the A8434EESTR-T require external compensation components for stability?
No, the A8434EESTR-T is internally compensated and requires no external compensation components. Stability is ensured by fixed-frequency 1 MHz oscillator and optimized control loop design. Only four external ceramic capacitors are needed: CIN (1 µF), COUT (1 µF), and charge pump caps C1/C2 (1 µF each), all specified as X5R/X7R dielectric for low ESR and temperature stability.
A8434EESTR-T Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Allegro MicroSystems
- Series:
- -
- Package/Case:
- 16-WFQFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Type:
- DC DC Regulator
- Topology:
- Switched Capacitor (Charge Pump)
- Internal Switch(s):
- Yes
- Number of Outputs:
- 6
- Voltage - Supply (Min):
- 2.7V
- Voltage - Supply (Max):
- 5.5V
- Voltage - Output:
- -
- Current - Output / Channel:
- 30mA
- Frequency:
- 1MHz
- Dimming:
- Multi-Step
- Applications:
- Backlight, Camera Flash
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-QFN/MLP (3x3)
A8434EESTR-T FAQ
1.How can I place an order for A8434EESTR-T through Aetrix?
Please submit a Request for Quotation (RFQ) for A8434EESTR-T 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 A8434EESTR-T reliable?
The price and inventory of A8434EESTR-T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for A8434EESTR-T is usually 5 days.
3.What payment methods are accepted for A8434EESTR-T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for A8434EESTR-T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for A8434EESTR-T?
A8434EESTR-T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your A8434EESTR-T 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 A8434EESTR-T?
For technical support, including A8434EESTR-T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your A8434EESTR-T requirements.
6.How does Aetrix verify that A8434EESTR-T is sourced from the original manufacturer or authorized distributors?
All A8434EESTR-T 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 A8434EESTR-T meets industry standards.
7.What is the process for return or replacement of A8434EESTR-T?
All A8434EESTR-T units undergo pre-shipment inspection (PSI). If there is an issue with A8434EESTR-T, 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 A8434EESTR-T part is unused and in its original packaging.
Return procedure for A8434EESTR-T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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