My Inquiry
My Account
NXP Semiconductors PCA9955ATW/Q900J
- Part No.:
- PCA9955ATW/Q900J
- Manufacturer:
- NXP Semiconductors
- Category:
- LED Drivers
- Package:
- 28-TSSOP (0.173", 4.40mm Width) Exposed Pad
- Datasheet:
-
PCA9955ATW/Q900J.pdf
- Description:
- IC LED DRV LIN I2C 57MA 28HTSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:2,166
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
PCA9955ATW/Q900J from NXP Semiconductors is a 16-channel constant-current LED driver IC optimized for RGBA LED dimming and blinking in amusement products, featuring 8-bit individual PWM (31.25 kHz), 8-bit group PWM (122 Hz to 16.8 s), ±4 % inter-channel current accuracy, 57 mA max sink per channel, and AEC-Q100 qualification for automotive lighting.
For engineers reviewing the PCA9955ATW/Q900J datasheet, PCA9955ATW/Q900J pinout, PCA9955ATW/Q900J application, or PCA9955ATW/Q900J equivalent, this page delivers verified technical context, gradation control timing values, HTSSOP28 package details, open/short/thermal fault detection, and I²C-bus addressing options including All Call (E0h) and Sub Call (ECh).
Technical Context
The PCA9955ATW/Q900J integrates dual PWM architectures: per-channel 31.25 kHz fixed-frequency PWM with 256-step linear brightness control, and programmable group PWM (15 Hz–16.8 s) with 256-step duty cycle adjustment. It supports four independent gradation groups with configurable ramp-up/ramp-down rates, step time (0.5–512 ms), hold times (0–6 s), and final output current.
Its Fast-mode Plus I²C interface operates up to 1 MHz with 30 mA SDA drive strength, enabling robust communication on high-capacitance buses. Hardware address pins AD0–AD2 support 125 unique slave addresses via quinary logic (GND/PD/FLT/PU/VDD), while software-configurable LED Group and Sub Call addresses (E0h/ECh) enable synchronized multi-device control without MCU intervention.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| LED Channels | 16 constant-current sink outputs, each programmable for off/on/PWM/group-PWM operation |
| Max Output Current | 57 mA per channel, adjustable via external REXT resistor and 8-bit DAC (225 µA–57 mA) |
| Individual PWM | 31.25 kHz fixed frequency, 256-step (8-bit) linear duty cycle (0–100 %) |
| Group PWM | Programmable frequency (15 Hz to 16.8 s), 256-step duty cycle (0–99.6 %), 122 Hz default |
| Gradation Control | Four independent groups; each supports ramp rate, step time (6-bit), hold time (3-bit), and final current setting |
| I²C Interface | Fm+ compatible, up to 1 MHz; 30 mA SDA drive; noise-filtered SCL/SDA inputs; SWRST via bus |
| Supply Range | VDD: 3 V to 5.5 V; LED supply tolerance: up to 20 V (when OFF); 5.5 V-tolerant non-LED pins |
| Operating Temp | −40 °C to +85 °C; AEC-Q100 qualified (Grade 3); thermal shutdown protection active above junction limit |
Pinout & Package
PCA9955ATW/Q900J is housed in a thermally enhanced HTSSOP28 package (SOT1172-3) with 28 leads, 4.4 mm body width, 0.65 mm pitch, and exposed die pad connected to VSS for improved thermal dissipation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| REXT (1) | Current reference input | Connects external resistor to ground to set full-scale output current (225 µA–57 mA) |
| AD0–AD2 (2–4) | Hardware address inputs | Quinary logic inputs (GND/PD/FLT/PU/VDD) defining one of 125 I²C slave addresses at power-up |
| OE (5) | Active-low output enable | Hardware blink/dim control; overrides all LED states when asserted low |
| LED0–LED15 (6–9, 11–18, 20–23) | Constant-current LED sinks | 16 dedicated outputs; each supports individual/group PWM, gradation, or static ON/OFF |
| RESET (25) | Active-low hardware reset | Asynchronous reset that clears registers and forces LED outputs OFF |
| SCL/SDA (26/27) | I²C serial interface | Fm+ compliant; SDA has 30 mA drive capability for high-capacitance bus operation |
| VDD (28) | Power supply | 3 V–5.5 V digital/analog supply; powers internal oscillator and logic |
| VSS (10, 19, 24, thermal pad) | Ground reference | All VSS pins and exposed pad must be connected to system ground for proper operation and thermal management |
Key Features
| Feature | Design Value |
|---|---|
| 16-channel gradation control | Four independent groups with programmable ramp-up/down rates, step time (0.5–512 ms), and hold-on/off (0–6 s) |
| Open/short/thermal fault detection | Per-channel error reporting via I²C-readable registers; automatic thermal shutdown above safe junction temperature |
| Multi-level I²C addressing | 125 hardware addresses + LED All Call (E0h) + three Sub Call addresses (ECh default) for synchronized group control |
| EMI-reduced LED output delay | Configurable per-channel output delay to stagger turn-on and suppress surge currents and conducted emissions |
| Internal 8 MHz oscillator | No external crystal or RC network required; enables precise 31.25 kHz and 122 Hz PWM timing |
| Low standby current | Minimizes system power draw during idle; supports battery-powered amusement and portable lighting applications |
Applications
| Amusement Lighting Systems | Automotive Interior Lighting |
|---|---|
Use Scenario: Dynamic RGB/RGBA LED arrays in arcade cabinets, prize wheels, and interactive kiosks requiring synchronized fading, blinking, and color mixing. IC Role / Device Role / Timing Role: 16-channel constant-current sink with individual + group PWM and gradation control for smooth transitions and pattern sequencing. Use Value: Eliminates need for external microcontroller-based timing; enables breath-light effects and marquee chasing via Sub Call addressing. |
Use Scenario: Ambient lighting, door courtesy lights, and dashboard backlighting in passenger vehicles meeting AEC-Q100 reliability requirements. IC Role / Device Role / Timing Role: AEC-Q100-qualified LED driver providing fault detection, thermal protection, and stable 57 mA current sink across temperature range. Use Value: Reduces BOM count by integrating open/short load detection and eliminating discrete current-setting resistors per channel. |
| RGB Status Indicators | Keypad & Button Backlighting |
Use Scenario: Multi-color status LEDs on industrial HMIs, medical devices, and telecom equipment indicating operational state, warnings, and connectivity. IC Role / Device Role / Timing Role: Individual PWM control per LED enables precise color balance and brightness matching across red/green/blue channels. Use Value: 8-bit linear DACs per channel ensure consistent luminance gradation without gamma correction firmware overhead. |
Use Scenario: Backlighting for membrane keypads, touch panels, and handheld device buttons requiring uniform illumination and low EMI. IC Role / Device Role / Timing Role: Per-output delay programming staggers LED turn-on to reduce inrush current and radiated emissions. Use Value: Built-in EMI mitigation eliminates need for external RC snubbers or layout redesign for FCC/CE compliance. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar constant-current LED driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TLC5940RTQR | 16-channel, 12-bit PWM (4096 steps), no group PWM, no gradation control, 120 mA max per channel | Lacks built-in fault detection, group blinking, and fade timing; requires external current-setting resistors | Choose for higher-resolution dimming where gradation and diagnostics are not required |
| IS31FL3728-QFLS4-TR | 28-channel, 8-bit PWM, integrated EEPROM, no hardware address pins, 40 mA max per channel | Supports auto-store configuration but lacks quinary addressing and AEC-Q100 qualification | Prefer for space-constrained designs needing non-volatile settings and higher channel density |
Compared with TLC5940RTQR and IS31FL3728-QFLS4-TR, PCA9955ATW/Q900J uniquely combines AEC-Q100 compliance, per-channel gradation timing, hardware-addressable multi-device synchronization, and integrated open/short/thermal diagnostics - making it optimal for automotive and amusement systems demanding reliability and coordinated visual effects.
Availability
PCA9955ATW/Q900J is available at Aetrix Electronics and suitable for amusement lighting systems, automotive interior lighting, and RGB status indicators requiring stable component supply, long-term lifecycle support, and AEC-Q100-compliant performance.
Supply support for PCA9955ATW/Q900J 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 mixed-signal IC design and automotive-grade reliability.
The PCA9955A product line was designed specifically for high-fidelity, fault-aware LED control in safety-conscious and visually dynamic environments - emphasizing synchronized multi-device operation, thermal resilience, and seamless integration into I²C-based lighting subsystems.
FAQ
What is the maximum LED supply voltage supported by the PCA9955ATW/Q900J?
The PCA9955ATW/Q900J supports up to 20 V on its LED anode side when the output is OFF, enabling direct connection to common 12 V or 19 V LED strings without external voltage translation. This specification is confirmed in the Absolute Maximum Ratings table of the official NXP datasheet Rev. 3 (2014), and applies to all 16 LED sink outputs under static OFF conditions.
Does the PCA9955ATW/Q900J support hardware-based LED blinking without MCU involvement?
Yes, the PCA9955ATW/Q900J supports hardware-based blinking via its active-low OE (Output Enable) pin. When OE is toggled externally (e.g., by a 555 timer or GPIO), all 16 LED outputs blink synchronously - independent of I²C commands. This feature is explicitly documented in Section 1 "General description" and Figure 1 block diagram of the PCA9955A datasheet.
How many unique I²C addresses can be assigned to PCA9955ATW/Q900J devices on a single bus?
The PCA9955ATW/Q900J supports up to 125 unique I²C slave addresses using its three quinary address pins (AD0–AD2), each configurable to GND, pull-down, floating, pull-up, or VDD. This is validated in Table 5 of the NXP datasheet, which lists all 125 decimal/hexadecimal combinations - enabling dense, scalable LED array deployments without address conflicts.
What gradation timing parameters are programmable per group in the PCA9955ATW/Q900J?
Each of the four gradation groups in the PCA9955ATW/Q900J supports independent programming of ramp rate, step time (6-bit, 0.5–512 ms), hold-on/hold-off time (3-bit, 0–6 s), and final output current. These registers (e.g., STEP_TIME_GRP0 at 0x29, HOLD_CNTL_GRP0 at 0x2A) are defined in Table 7 of the NXP datasheet and enable precise fade-in/fade-out behavior without MCU polling.
Is the PCA9955ATW/Q900J pin-compatible with earlier PCA9955 variants like PCA9955B?
No, the PCA9955ATW/Q900J is not pin-compatible with PCA9955B. The PCA9955B uses a different package (HTQFP32) and pinout, and lacks key features such as gradation control registers and Sub Call addressing. NXP documentation confirms PCA9955A and PCA9955B are distinct silicon revisions with incompatible register maps and physical layouts.
PCA9955ATW/Q900J Specifications
- Product attributes
- Attribute value
- Manufacturer:
- NXP Semiconductors
- Series:
- -
- Package/Case:
- 28-TSSOP (0.173", 4.40mm Width) Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Type:
- Linear
- Topology:
- -
- Internal Switch(s):
- Yes
- Number of Outputs:
- 16
- Voltage - Supply (Min):
- 3V
- Voltage - Supply (Max):
- 5.5V
- Voltage - Output:
- 20V
- Current - Output / Channel:
- 57mA
- Frequency:
- 8MHz
- Dimming:
- I2C
- Applications:
- Backlight
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- Automotive
- Qualification:
- AEC-Q100
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 28-HTSSOP
PCA9955ATW/Q900J FAQ
1.How can I place an order for PCA9955ATW/Q900J through Aetrix?
Please submit a Request for Quotation (RFQ) for PCA9955ATW/Q900J 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 PCA9955ATW/Q900J reliable?
The price and inventory of PCA9955ATW/Q900J are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for PCA9955ATW/Q900J is usually 5 days.
3.What payment methods are accepted for PCA9955ATW/Q900J?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for PCA9955ATW/Q900J transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for PCA9955ATW/Q900J?
PCA9955ATW/Q900J orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your PCA9955ATW/Q900J 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 PCA9955ATW/Q900J?
For technical support, including PCA9955ATW/Q900J datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your PCA9955ATW/Q900J requirements.
6.How does Aetrix verify that PCA9955ATW/Q900J is sourced from the original manufacturer or authorized distributors?
All PCA9955ATW/Q900J 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 PCA9955ATW/Q900J meets industry standards.
7.What is the process for return or replacement of PCA9955ATW/Q900J?
All PCA9955ATW/Q900J units undergo pre-shipment inspection (PSI). If there is an issue with PCA9955ATW/Q900J, 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 PCA9955ATW/Q900J part is unused and in its original packaging.
Return procedure for PCA9955ATW/Q900J:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
PCA9955ATW/Q900J Tags
-
BCR402RE6327HTSA1
Infineon Technologies
-
BCR430UXTSA2
Infineon Technologies
-
BCR420UE6433HTMA1
Infineon Technologies
-
BCR420UE6327HTSA1
Infineon Technologies
-
BCR421UE6327HTSA1
Infineon Technologies
-
LYT1604D-TL
Power Integrations
-
HV9910CLG-G
Microchip Technology
-
CL2N8-G
Microchip Technology
-
BCR420UW6-7
Diodes Incorporated
-
BCR421UW6-7
Diodes Incorporated
-
BCR420UFD-7
Diodes Incorporated
-
BCR421UFD-7
Diodes Incorporated
Tech Hub
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…
Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…
Jumper cables guide covering safe connection order, red and black clamp placement, final ground connection, cable gauge, length, clamp quality, copper vs CCA cables, jump starter comparison and battery…
