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NXP Semiconductors PCF8551ATT/AY
- Part No.:
- PCF8551ATT/AY
- Manufacturer:
- NXP Semiconductors
- Category:
- Display Drivers
- Package:
- 48-TFSOP (0.240", 6.10mm Width)
- Datasheet:
-
PCF8551ATT/AY.pdf
- Description:
- LCD DRIVER
- Quantity:
- Payment:
- Shipping:
Inventory:3,862
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Product details
Overview
PCF8551ATT/AY 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 integrated bias generation - used in battery-powered metering and healthcare displays.
For engineers reviewing the PCF8551ATT/AY datasheet, PCF8551ATT/AY pinout, PCF8551ATT/AY application, or PCF8551ATT/AY equivalent, this page delivers verified technical context, TSSOP48 package mapping, real-time display control register behavior, and validated alternative options for 36×4 LCD systems requiring stable bias, blinking, and auto-incremented RAM loading.
Technical Context
The PCF8551ATT/AY implements a fully integrated I²C-bus LCD controller with internal oscillator (32–128 Hz frame rate), programmable 1/2 or 1/3 LCD bias, and selectable 1:1 (static) to 1:4 multiplex drive - all managed via four command registers (Device_ctrl, Display_ctrl_1/2, Software_reset). It supports up to 144 independent segment elements across four backplanes.
Its display RAM organization maps 36 segments × 4 backplanes into 18 dedicated byte-addressed registers (04h–17h), with auto-increment addressing and frame/line inversion modes to suppress DC voltage buildup. Pin CLK serves as either internal oscillator output or external clock input, configurable via Device_ctrl register bit COE/OSC.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Interface | I²C-bus, 400 kHz max - enables 2-wire host communication with standard address decoding and ACK/NACK protocol handling. |
| Segment/Backplane Count | 36 segment drivers + 4 backplane outputs - supports up to 18 numeric 7-segment digits, 9 alphanumeric 14-segment characters, or arbitrary 144-element graphics. |
| Supply Range | VDD and VLCD: 1.8 V to 5.5 V - allows single-supply operation and flexible LCD voltage scaling independent of logic supply. |
| Drive Modes | Static, 1:2, 1:3, or 1:4 multiplex - selected via MUX[1:0] bits; each mode configures active COM outputs and internal waveform timing. |
| Bias Configuration | Selectable 1/2 or 1/3 bias - determines RMS voltage ratios (e.g., 1:4/1/3 → Von/Voff = 1.732) and directly impacts contrast and required VLCD level. |
| Blink Frequency | 0.5 Hz, 1 Hz, or 2 Hz - software-controlled via BL[1:0]; full-display blink achieved without host CPU intervention during active frames. |
| Operating Temperature | −40 °C to +85 °C - qualified for industrial and consumer metering environments with guaranteed functionality across full range. |
Pinout & Package
TSSOP48 package (SOT362-1), plastic thin shrink small outline, 48 leads, body width 6.1 mm - surface-mount compatible with standard reflow profiles and IPC-7351B land patterns.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| SEG0–SEG35 | LCD segment output | 36 open-drain CMOS outputs driving LCD segment electrodes; logic-high disables segment, logic-low enables (with backplane phase). |
| COM0–COM3 | LCD backplane output | 4 complementary outputs generating time-multiplexed backplane waveforms; synchronized with segment data per selected MUX mode. |
| VLCD | LCD supply voltage | Independent analog supply rail (1.8–5.5 V); feeds internal bias generator and segment/backplane drivers - decoupling mandatory. |
| VDD / VSS | Digital supply / ground | VDD powers logic core and I²C interface (1.8–5.5 V); VSS is common reference for all supplies and digital I/O. |
| SCL / SDA | I²C clock / data | Standard bidirectional I²C interface pins; support repeated START, 7-bit slave address (0x70 default), and register auto-increment writes. |
| CLK | Oscillator I/O | Configurable as internal oscillator output (COE=1) or external clock input (OSC=1); 50% duty cycle when enabled; must be left open if unused. |
| PORE | Power-On Reset enable | Active-high input; connect to VDD to enable internal POR (resets registers to defaults); tie to VSS or float to disable and require software reset. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated LCD bias generator | On-chip fractional voltage divider with buffered 1/2 or 1/3 taps - eliminates external resistors and reduces layout sensitivity to VLCD ripple. |
| Auto-increment display RAM access | Single START + address byte loads 04h–17h sequentially - simplifies host firmware for full 144-segment updates without manual address management. |
| Versatile blinking control | Hardware-timed blink at 0.5/1/2 Hz - operates independently after setup; no CPU polling or timer interrupts required during active display. |
| Independent VLCD/VDD supplies | Separate analog (VLCD) and digital (VDD) rails - enables optimization of LCD contrast while maintaining robust I²C signaling under varying battery conditions. |
| Power-down mode retention | Registers preserved, bus remains responsive, oscillator disabled - achieves ultra-low standby current while allowing instant wake-up via DE bit toggle. |
Applications
| Metering Equipment | Consumer Healthcare Devices |
|---|---|
|
Use Scenario: Digital electricity/water/gas meters with multi-digit LCD readouts and status icons. IC Role / Device Role / Timing Role: Primary LCD segment driver managing 4-backplane, 36-segment display with built-in bias and frame-rate control. Use Value: Enables long-life battery operation via ultra-low power consumption and eliminates need for external bias circuitry. |
Use Scenario: Portable blood glucose monitors and digital thermometers with alphanumeric LCDs. IC Role / Device Role / Timing Role: Standalone display controller interfacing directly to MCU over I²C, handling all segment timing and blinking. Use Value: Reduces BOM count by integrating oscillator, bias, and display RAM - critical for compact, cost-sensitive medical devices. |
| Battery Operated Devices | Measuring Equipment |
|
Use Scenario: Handheld multimeters and portable environmental sensors with segmented LCDs. IC Role / Device Role / Timing Role: Low-voltage LCD driver supporting 1.8 V operation and static-to-1:4 multiplex flexibility for diverse panel types. Use Value: Maintains display readability across wide battery discharge range (1.8–5.5 V) without external level-shifting or voltage regulation. |
Use Scenario: Benchtop test equipment (e.g., LCR meters, oscilloscope front panels) with high-reliability segmented displays. IC Role / Device Role / Timing Role: Industrial-grade segment driver with −40 °C to +85 °C qualification and robust ESD protection on all pins. Use Value: Ensures consistent segment contrast and flicker-free operation under thermal stress and electromagnetic noise. |
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/AY | SPI interface (5 MHz) instead of I²C; CE pin replaces T1; SDIO replaces SDA; identical TSSOP48 package and register map. | Requires 3-wire SPI host interface; not compatible with I²C-only systems; same display capabilities and bias features. | Select when host MCU lacks I²C hardware or requires higher update bandwidth than 400 kHz I²C permits. |
| PCF8576CTT/AY | Higher segment count (48 segments × 4 backplanes); same I²C interface, supply range, and bias architecture; TSSOP48 package. | Supports larger displays (up to 192 segments); register map differs slightly; requires updated firmware for extended RAM addressing. | Choose for future-proofing or when display expansion beyond 36 segments is anticipated in same footprint. |
Compared with PCF8551BTT/AY and PCF8576CTT/AY, the PCF8551ATT/AY provides optimal balance of I²C simplicity, ultra-low power, and proven reliability in 36×4 LCD metering applications - with no trade-offs in bias control, temperature range, or blink functionality.
Availability
PCF8551ATT/AY is available at Aetrix Electronics and suitable for metering equipment, consumer healthcare devices, and battery operated devices requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.
Supply support for PCF8551ATT/AY 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 company headquartered in Eindhoven, Netherlands, specializing in secure connectivity solutions for automotive, industrial, and IoT applications.
The PCF8551ATT/AY belongs to NXP's universal LCD segment driver product line, designed specifically for ultra-low-power, microcontroller-offloaded display control in resource-constrained embedded systems.
FAQ
What interface does the PCF8551ATT/AY use, and what is its maximum speed?
The PCF8551ATT/AY uses a standard I²C-bus interface with a maximum clock frequency of 400 kHz. It supports 7-bit slave addressing (default 0x70), repeated START conditions, and ACK/NACK handshaking. This interface allows simple two-wire connection to microcontrollers and eliminates the need for additional SPI or parallel bus resources - making it ideal for space- and pin-constrained designs using the PCF8551ATT/AY.
How many LCD segments and backplanes does the PCF8551ATT/AY support?
The PCF8551ATT/AY supports exactly 36 segment drivers and 4 backplane outputs, enabling configurations such as 18 numeric 7-segment digits, 9 alphanumeric 14-segment characters, or any custom arrangement totaling up to 144 individual LCD elements. This fixed 36×4 topology is hardwired in silicon and confirmed in the PCF8551ATT/AY datasheet Section 1 and Figure 1.
Does the PCF8551ATT/AY include an internal oscillator and LCD bias generator?
Yes, the PCF8551ATT/AY integrates both an internal oscillator (configurable for 32/64/96/128 Hz frame rates) and an on-chip LCD bias generator with buffered 1/2 or 1/3 voltage taps. These eliminate external components and reduce layout complexity - a key design advantage confirmed in the PCF8551ATT/AY General Description and Section 8.1 of the datasheet.
What are the supply voltage requirements for the PCF8551ATT/AY?
The PCF8551ATT/AY requires two independent supplies: VDD (digital logic and I²C interface) and VLCD (LCD analog drive), both rated from 1.8 V to 5.5 V. This dual-rail flexibility allows optimized contrast control and battery longevity - a specification explicitly defined in Section 2 Features and Benefits and Table 11 of the PCF8551ATT/AY datasheet.
Can the PCF8551ATT/AY drive static LCDs, or is it limited to multiplexed displays?
The PCF8551ATT/AY supports static drive mode (1:1) as well as 1:2, 1:3, and 1:4 multiplex configurations - selected via MUX[1:0] bits in Display_ctrl_1 register (address 02h). In static mode, only COM0 is active and all 36 segments map directly to a single backplane, enabling simple bar-graph or fixed-symbol displays - fully documented in Section 7.2.2 and Table 10 of the PCF8551ATT/AY datasheet.
PCF8551ATT/AY Specifications
- Product attributes
- Attribute value
- Manufacturer:
- NXP Semiconductors
- Series:
- -
- Package/Case:
- 48-TFSOP (0.240", 6.10mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Display Type:
- LCD
- Configuration:
- 36 Segment
- 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 (TA)
- Grade:
- Automotive
- Qualification:
- AEC-Q100
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 48-TSSOP
PCF8551ATT/AY FAQ
1.How can I place an order for PCF8551ATT/AY through Aetrix?
Please submit a Request for Quotation (RFQ) for PCF8551ATT/AY 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/AY reliable?
The price and inventory of PCF8551ATT/AY are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for PCF8551ATT/AY is usually 5 days.
3.What payment methods are accepted for PCF8551ATT/AY?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for PCF8551ATT/AY transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for PCF8551ATT/AY?
PCF8551ATT/AY orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your PCF8551ATT/AY 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/AY?
For technical support, including PCF8551ATT/AY datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your PCF8551ATT/AY requirements.
6.How does Aetrix verify that PCF8551ATT/AY is sourced from the original manufacturer or authorized distributors?
All PCF8551ATT/AY 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/AY meets industry standards.
7.What is the process for return or replacement of PCF8551ATT/AY?
All PCF8551ATT/AY units undergo pre-shipment inspection (PSI). If there is an issue with PCF8551ATT/AY, 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/AY part is unused and in its original packaging.
Return procedure for PCF8551ATT/AY:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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