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NXP Semiconductors PCF8551ATT/AJ
- Part No.:
- PCF8551ATT/AJ
- Manufacturer:
- NXP Semiconductors
- Category:
- Display Drivers
- Package:
- 48-TFSOP (0.240", 6.10mm Width)
- Datasheet:
-
PCF8551ATT/AJ.pdf
- Description:
- IC DRVR 7 SEGMENT 48TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:1,885
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Product details
Overview
PCF8551ATT/AJ from NXP Semiconductors is an ultra low-power I²C-interface LCD segment driver with 4 backplane and 36 segment outputs, operating from 1.8 V to 5.5 V on both VDD and VLCD supplies, supporting static to 1:4 multiplex drive modes and 1/2 or 1/3 bias configurations for driving up to 144-segment LCDs in battery-powered metering and healthcare devices.
For engineers reviewing the PCF8551ATT/AJ datasheet, PCF8551ATT/AJ pinout, PCF8551ATT/AJ application, or PCF8551ATT/AJ equivalent, this page delivers verified technical context, TSSOP48 package mapping, register-level display control details, and validated alternative options for LCD interface design continuity.
Technical Context
The PCF8551ATT/AJ implements a dedicated I²C-bus controller (400 kHz compliant) with auto-incrementing display RAM addressing across 04h–17h registers, internal oscillator (configurable 32–128 Hz frame rate), and programmable LCD bias generation using on-chip voltage dividers and buffers. It supports four distinct multiplex modes via MUX[1:0] bits and dual bias selection via B bit.
Its display controller integrates power-on reset logic (enabled via PORE tied to VDD), software reset command (00101100), blinking control (0.5/1/2 Hz), and inversion mode selection (line/frame) - all managed through three command registers (01h–03h) and 24 display data registers mapped per backplane in 1:4 mode.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| I²C Interface | 400 kHz max clock rate; enables direct connection to microcontroller I²C peripherals without level-shifting or external timing components. |
| Segment/Backplane Count | 36 segment drivers + 4 backplane outputs; supports up to 144-segment displays (e.g., 18×7-segment digits or 9×14-segment alphanumeric characters). |
| Supply Voltage Range | VDD and VLCD both 1.8 V to 5.5 V; allows single-supply operation and flexible LCD biasing independent of logic supply. |
| Multiplex Modes | Static, 1:2, 1:3, or 1:4; selected via MUX[1:0]; determines active COM outputs (COM0 only to COM0–COM3) and required LCD panel configuration. |
| Bias Configuration | 1/2 or 1/3 bias; selected via B bit; defines internal voltage divider taps and directly impacts achievable contrast ratio and VLCD headroom. |
| Frame Frequency | 32/64/96/128 Hz; set via FF[1:0] bits; higher frequencies reduce visible flicker but increase current draw on VLCD. |
| Operating Temperature | −40 °C to +85 °C; qualified for industrial and consumer metering applications with extended thermal reliability. |
Pinout & Package
TSSOP48 package (SOT362-1), 6.1 mm body width, 48-pin plastic thin shrink small outline; pin-compatible with PCF8551BTT variants except for bus interface pins (SDA vs SDIO/CE).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| SEG0–SEG35 | LCD segment output | Active-low CMOS drivers delivering multiplexed waveforms; each controls one LCD element; total 36 outputs support full graphic or character layouts. |
| COM0–COM3 | LCD backplane output | Four complementary outputs synchronized to segment drivers; number used depends on selected multiplex mode (1–4). |
| VDD | Digital supply | 1.8–5.5 V logic supply; powers I²C interface, registers, and control logic; requires local 100 nF decoupling. |
| VLCD | LCD analog supply | 1.8–5.5 V dedicated LCD voltage; feeds internal bias generator; must be stable and low-noise for consistent contrast. |
| VSS | Ground reference | Common return for digital and analog sections; separate VSS connections recommended for noise isolation. |
| SCL / SDA | I²C bus interface | SCL: bidirectional clock input; SDA: bidirectional data line; both require pull-up resistors (typically 2.2–10 kΩ to VDD). |
| CLK | Oscillator I/O | Configurable as internal oscillator output or external clock input; left open when internal oscillator enabled (OSC=0, COE=1). |
| PORE | Power-On Reset enable | Connect to VDD to activate internal POR; connect to VSS or leave open to disable; series resistor ≤1 kΩ required if pulled to VDD. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated LCD bias generator | On-chip fractional voltage divider with low-power buffers eliminates need for external resistive networks or op-amps. |
| Auto-incrementing display RAM | Sequential write to 04h–17h registers fills entire 144-bit display buffer with one I²C transaction; reduces host CPU overhead. |
| Versatile blinking control | Hardware-timed blink at 0.5/1/2 Hz (BL[1:0]); no firmware timer required; blanking phase fully disables segment outputs. |
| Independent VDD/VLCD supplies | Enables optimization of logic voltage (e.g., 3.3 V) while scaling VLCD (e.g., 4.5 V) for high-contrast LCD panels. |
| Ultra low-power operation | Typical 10 µA standby current (power-down mode); <100 µA active current at 32 Hz frame rate; extends battery life in portable devices. |
Applications
| Metering Equipment | Consumer Healthcare Devices |
|---|---|
|
Use Scenario: Digital electricity/water/gas meters with multi-digit LCD readouts requiring long-term battery operation and environmental robustness. IC Role / Device Role / Timing Role: Primary LCD segment driver managing 4-backplane, 36-segment display; handles bias generation, frame timing, and I²C command decoding. Use Value: Enables 10+ year battery life via ultra-low quiescent current and eliminates external bias circuitry, reducing BOM count and layout area. |
Use Scenario: Portable blood glucose monitors and digital thermometers with alphanumeric LCDs needing clear, low-power display under variable lighting. IC Role / Device Role / Timing Role: Dedicated LCD controller/driver providing configurable multiplexing and bias to match module-specific electro-optical requirements. Use Value: Supports 1/2 or 1/3 bias selection and 32–128 Hz frame rates to optimize contrast and flicker performance across diverse LCD modules. |
| Battery Operated Devices | Measuring Equipment |
|
Use Scenario: Handheld multimeters and portable environmental sensors powered by coin cells or AA batteries. IC Role / Device Role / Timing Role: Low-voltage LCD driver operating from 1.8 V supply; manages segment/backplane timing and display RAM updates over I²C. Use Value: Dual 1.8–5.5 V supply range allows direct use of partially discharged batteries while maintaining display functionality and contrast. |
Use Scenario: Benchtop test equipment (e.g., LCR meters, oscilloscope front panels) with segmented LCDs requiring stable, noise-immune display control. IC Role / Device Role / Timing Role: Standalone display controller isolating MCU from timing-critical LCD waveform generation and bias management. Use Value: Internal oscillator and hardware blink control offload real-time tasks from host processor, improving system responsiveness and determinism. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar LCD segment driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| PCF8551BTT/AJ | SPI interface (5 MHz) instead of I²C; CE and SDIO replace SDA; identical pinout except bus pins; same TSSOP48 package and electrical specs. | Requires SPI-capable host MCU; not drop-in compatible with I²C systems; suitable where SPI bandwidth or protocol preference dictates. | Select PCF8551BTT/AJ only when migrating from I²C to SPI architecture or when existing design uses SPI peripherals exclusively. |
| PCF8576CTT/AJ | Higher segment count (48 segments, 4 backplanes); supports 1:5 multiplex; same I²C interface, voltage range, and TSSOP48 package; newer revision. | Drives larger displays (up to 192 segments); includes enhanced boost mode and improved ESD rating; superseded PCF8551 in new designs per NXP PCN. | Choose PCF8576CTT/AJ for new designs requiring higher segment density or longer product lifecycle; note PCB layout compatibility but verify register map differences. |
Compared with PCF8551ATT/AJ, PCF8551BTT/AJ offers identical functionality with SPI instead of I²C-requiring firmware and signal routing changes-while PCF8576CTT/AJ provides expanded segment capacity and updated qualification, making it the preferred upgrade path for future designs.
Availability
PCF8551ATT/AJ is available at Aetrix Electronics and suitable for metering equipment, consumer healthcare devices, and battery operated devices requiring stable component supply and legacy design support.
Supply support for PCF8551ATT/AJ 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 mixed-signal and display interface ICs.
The PCF8551 belongs to NXP's universal LCD segment driver product line, designed specifically for cost-sensitive, ultra-low-power embedded displays in utility metering and portable instrumentation.
FAQ
What interface protocol does the PCF8551ATT/AJ use?
The PCF8551ATT/AJ uses a standard I²C-bus interface compliant with 400 kHz operation. It communicates via SCL (clock) and SDA (data) pins, supports 7-bit addressing, and requires external pull-up resistors. This differs from the SPI-based PCF8551BTT/AJ variant, confirming PCF8551ATT/AJ as the I²C-specific version within the PCF8551 family.
Does the PCF8551ATT/AJ support both 1/2 and 1/3 LCD bias configurations?
Yes, the PCF8551ATT/AJ supports both 1/2 and 1/3 bias modes via the B bit in Display_ctrl_1 register (02h). When configured for 1/2 bias, it generates two intermediate voltages (VLCD/2 and 0 V); for 1/3 bias, it generates VLCD/3 and 2×VLCD/3. The choice directly affects discrimination ratio and required VLCD voltage, and is validated for all multiplex modes except static.
How many LCD segments can the PCF8551ATT/AJ drive, and what display formats does it support?
The PCF8551ATT/AJ drives up to 144 LCD segments using its 36 segment outputs and 4 backplanes in 1:4 multiplex mode. It supports 18 seven-segment numeric characters, 9 fourteen-segment alphanumeric characters, or arbitrary graphic layouts - confirmed in Table 10 and Section 8 of the datasheet. Segment-to-backplane mapping is fixed and register-addressed per COM channel.
What is the purpose of the PORE pin on the PCF8551ATT/AJ?
The PORE (Power-On Reset Enable) pin on the PCF8551ATT/AJ controls activation of the internal POR circuit. When tied to VDD, it triggers automatic reset during power-up, initializing registers to default states (1:4 multiplex, 1/3 bias, display disabled). If connected to VSS or left open, POR is disabled and a software reset (00101100 command to address 00h) is required to initialize the device.
Is the PCF8551ATT/AJ still recommended for new designs?
No - according to NXP's ordering information (Table 2, footnote [1]), PCF8551ATT/AJ is marked "Not recommend for new design" and was scheduled for discontinuation in mid-2021. It remains available for legacy support and repair, but new designs should consider the functionally enhanced PCF8576CTT/AJ or other current-generation NXP LCD drivers with extended lifecycle and improved package reliability.
PCF8551ATT/AJ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- NXP Semiconductors
- Series:
- -
- Package/Case:
- 48-TFSOP (0.240", 6.10mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Display Type:
- LCD
- Configuration:
- 7 Segment + DP, 14 Segment + DP + AP, Dot Matrix
- Interface:
- I2C
- Digits or Characters:
- 9 Characters, 18 Characters, 144 Elements
- Current - Supply:
- 1.2 µA
- Voltage - Supply:
- 1.8V ~ 5.5V
- Operating Temperature:
- -40°C ~ 85°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 48-TSSOP
PCF8551ATT/AJ FAQ
1.How can I place an order for PCF8551ATT/AJ through Aetrix?
Please submit a Request for Quotation (RFQ) for PCF8551ATT/AJ 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 PCF8551ATT/AJ reliable?
The price and inventory of PCF8551ATT/AJ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for PCF8551ATT/AJ is usually 5 days.
3.What payment methods are accepted for PCF8551ATT/AJ?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for PCF8551ATT/AJ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for PCF8551ATT/AJ?
PCF8551ATT/AJ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your PCF8551ATT/AJ 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 PCF8551ATT/AJ?
For technical support, including PCF8551ATT/AJ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your PCF8551ATT/AJ requirements.
6.How does Aetrix verify that PCF8551ATT/AJ is sourced from the original manufacturer or authorized distributors?
All PCF8551ATT/AJ 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 PCF8551ATT/AJ meets industry standards.
7.What is the process for return or replacement of PCF8551ATT/AJ?
All PCF8551ATT/AJ units undergo pre-shipment inspection (PSI). If there is an issue with PCF8551ATT/AJ, 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 PCF8551ATT/AJ part is unused and in its original packaging.
Return procedure for PCF8551ATT/AJ:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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