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Texas Instruments LM8328TMX/NOPB
- Part No.:
- LM8328TMX/NOPB
- Manufacturer:
- Texas Instruments
- Category:
- Specialized
- Package:
- 25-WFBGA, DSBGA
- Datasheet:
-
LM8328TMX/NOPB.pdf
- Description:
- IC INTFACE SPECIALIZED 25DSBGA
- Quantity:
- Payment:
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Product details
Overview
LM8328TMX/NOPB from Texas Instruments is a mobile I/O companion IC designed to offload keypad scanning and provide programmable GPIO expansion, three independent PWM outputs for LED brightness control, and I²C-compatible ACCESS.bus host interface. It operates from a single 1.8V ±10% supply, integrates an internal RC oscillator and power-on reset, and supports up to 8×12 keypad matrices plus 8 special-function keys in a 25-pin DSBGA package for compact handheld applications.
For engineers reviewing the LM8328TMX/NOPB datasheet, LM8328TMX/NOPB pinout, LM8328TMX/NOPB application, or LM8328TMX/NOPB equivalent, key selection considerations include its 25-ball DSBGA footprint, default I²C slave address 0x88, 100/400 kHz ACCESS.bus timing, HALT mode power management, and register-based PWM scripting capability for autonomous LED control without host intervention.
Technical Context
The LM8328TMX/NOPB implements a dedicated keypad scan engine with configurable settle (4–16 ms) and debounce (4–16 ms) times, supporting up to four simultaneous key presses stored in KBDCODE[3:0] registers and a 15-byte FIFO for key events. Its interrupt architecture includes raw and masked keyboard interrupt status (KBDRIS/KBDMIS), with IRQN assertion on rising/falling edge or pulse for wake-up from HALT mode.
Its three PWM channels operate from a dedicated 32.768 kHz clock, each with a 64-byte script buffer supporting RAMP, SET_PWM, GO_TO_START, BRANCH, TRIGGER, and END commands - enabling self-sustaining LED fade, blink, and synchronized multi-channel effects without CPU polling. Script execution is triggered by host-initiated START commands and managed via TIMRIS interrupt flags.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage | 1.8 V ±10% - enables direct integration with low-voltage application processors and baseband ICs in mobile handsets. |
| Operating Temperature | −40°C to +85°C - qualified for consumer and industrial portable electronics environments. |
| I²C-Compatible Interface | ACCESS.bus at 100 kHz (Standard-Mode) and 400 kHz (Fast-Mode) - ensures interoperability with legacy and modern host controllers using standard I²C protocol layers. |
| Keypad Support | Up to 8×12 matrix + 8 SF keys = 104-key total - provides scalable input handling for feature-rich cordless phones and smart handhelds. |
| PWM Channels | Three independent outputs with 64-byte script buffers - allows autonomous, synchronized LED modulation (e.g., breathing, color cycling) without host CPU overhead. |
| Halt Mode Current | Typical 1.2 µA at 1.98 V and +85°C - minimizes standby power in battery-powered devices during user inactivity. |
| Package | 25-pin DSBGA (2.13 mm × 2.13 mm, 0.4 mm pitch) - supports high-density PCB layouts in space-constrained mobile form factors. |
Pinout & Package
LM8328TMX/NOPB uses a 25-ball DSBGA package with bottom-side solder balls. Pin configuration is defined per TI SNLS328A datasheet Figure 1 and Signal Descriptions table. All pins support dual functionality (keypad I/O, GPIO, PWM, or interrupt), with reset, supply, ground, I²C, and keypad/PWM/IRQ functions assigned to specific ball positions.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| RESETN (C1) | Active-low system reset input | Allows host processor to force hardware reset of LM8328TMX/NOPB; synchronizes initialization sequence and clears internal state. |
| VCC (C4) | Primary power supply | Accepts 1.8 V ±10%; powers all internal logic, keypad drivers, and PWM circuitry - no external regulator required. |
| GND (C3) | Ground reference | Provides return path for all internal currents; must be connected to system ground plane for noise immunity and stable operation. |
| SCL (D1) | I²C clock input | Drives synchronous communication with host; supports clock stretching up to 100 µs during busy processing phases. |
| SDA (E1) | I²C data bidirectional line | Carries serial command/data traffic; open-drain structure requires external pull-up resistor to VCC. |
| IRQN/KPY11/PWM2 (E3) | Multi-function terminal | Configurable as active-low interrupt output (default), keypad Y11 row, or PWM channel 2 output - enables flexible board routing. |
| KPX0–KPX7 (A5, B4, D2, E2, A1, B1, A3, A4) | Keypad column / GPIO inputs or outputs | Eight programmable X-lines usable as keypad columns or general-purpose I/O with configurable pull-up/down resistors. |
| KPY0–KPY10 (D5, C5, B5, D4, B2, A2, B3, C2, D3, E4, E5) | Keypad row / GPIO / PWM outputs | Eleven Y-lines supporting keypad rows, GPIO, or PWM0–PWM2 outputs - KPY8–KPY10 are dedicated PWM outputs by default. |
Key Features
| Feature | Design Value |
|---|---|
| On-chip RC oscillator | Eliminates need for external crystal or clock source - reduces BOM count and PCB area in cost-sensitive designs. |
| Programmable HALT mode entry delay | Host-configurable inactivity timeout (default 1020 ms) - balances power savings against responsiveness in portable UI applications. |
| 15-byte key event FIFO with auto-clear | Stores press/release events with overflow detection; EVTCODE reads clear REVTINT flag - simplifies host polling logic. |
| Register-based command interpreter | Supports auto-increment addressing for multi-byte register access - accelerates host configuration and status reads/writes over I²C. |
| Dedicated PWM script execution engine | Each channel executes preloaded scripts autonomously - enables complex LED effects without host CPU cycles or real-time scheduling. |
Applications
| Cordless Phone Keypad Interface | Smart Handheld Device I/O Expansion |
|---|---|
|
Use Scenario: Integration into DECT cordless phone handsets requiring reliable 40+ key scanning, low-power standby, and LED status indication. IC Role / Device Role / Timing Role: Dedicated keypad controller and LED driver - handles matrix scanning, debouncing, and PWM modulation independently of baseband processor. Use Value: Reduces host processor interrupt load by >90% and extends battery life via sub-µA HALT current during idle periods. |
Use Scenario: Adding GPIO and LED control to compact Android-based handhelds where main SoC GPIOs are fully allocated. IC Role / Device Role / Timing Role: I/O expander and autonomous LED controller - provides 16+ configurable I/Os and three synchronized PWM outputs. Use Value: Enables dynamic UI feedback (e.g., breathing LEDs, button backlighting) without consuming host CPU time or memory resources. |
| Keyboard Applications with Special Function Keys | Low-Power Remote Control Interface |
|
Use Scenario: Feature-rich remote controls with alphanumeric keypads, navigation clusters, and dedicated function keys (e.g., volume, mute). IC Role / Device Role / Timing Role: Keypad manager with SF key support and interrupt-driven event reporting - decouples key handling from RF transmission timing. Use Value: Supports 104-key capacity including 8 SF keys, with programmable debounce ensuring robust operation across temperature and voltage ranges. |
Use Scenario: IR or Bluetooth remotes requiring ultra-low standby current and responsive wake-up on keypress. IC Role / Device Role / Timing Role: Low-power I/O hub with wake-on-keypress and fast HALT exit - resumes full operation within <100 µs after IRQN assertion. Use Value: Achieves typical 1.2 µA HALT current at +85°C, enabling multi-year battery life in coin-cell powered remotes. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar I/O companion and keypad controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TCA6424A | 24-bit I²C GPIO expander with interrupt but no keypad scan engine or PWM; requires external firmware for key detection. | Lacks integrated keypad matrix scanning, debounce, and event buffering - demands host CPU resources for key processing. | Select when only GPIO expansion is needed and host can manage key scanning logic. |
| PCA9555 | 16-bit I²C I/O expander with interrupt and reset, no keypad or PWM functionality; no internal oscillator or HALT mode. | No native keyscan support, no PWM outputs, higher active current (>100 µA), and no low-power sleep states. | Choose for basic I/O extension where power efficiency and autonomous LED control are not required. |
Compared with TCA6424A and PCA9555, LM8328TMX/NOPB uniquely integrates keypad scanning, 15-event FIFO, three autonomous PWM channels, and sub-µA HALT mode - delivering complete human-interface offload in a single 2.13 mm × 2.13 mm package without host firmware overhead.
Availability
LM8328TMX/NOPB is available at Aetrix Electronics and suitable for cordless phones, smart handheld devices, keyboard interfaces, and low-power remote controls requiring stable component supply, long-term lifecycle support, and consistent parametric performance across production batches.
Supply support for LM8328TMX/NOPB 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
Texas Instruments is a global semiconductor company headquartered in Dallas, Texas, delivering analog and embedded processing solutions for industrial, automotive, and personal electronics markets.
The LM8328TMX/NOPB belongs to TI's Mobile I/O Companion product line, engineered specifically to reduce host processor burden in portable devices through integrated keypad scanning, GPIO expansion, and autonomous LED control.
FAQ
What is the default I²C slave address for LM8328TMX/NOPB?
The LM8328TMX/NOPB ships with a default I²C-compatible ACCESS.bus slave address of 0x88. This address can be changed via host configuration, and a Global Call Reset (write 0x06 to slave address 0x00) restores the default value. The device supports Standard-Mode (100 kHz) and Fast-Mode (400 kHz) operation exclusively as a slave.
How does LM8328TMX/NOPB handle multiple simultaneous key presses?
The LM8328TMX/NOPB supports up to four simultaneous key presses. Pressed keys are stored in KBDCODE0–KBDCODE3 registers, with the MULTIKEY flag set in KBDCODE0 indicating additional presses. All events are also captured in the 15-byte EVTCODE FIFO, enabling host software to reconstruct full key sequences even during rapid input.
Can LM8328TMX/NOPB operate without an external clock source?
Yes. LM8328TMX/NOPB integrates an internal RC oscillator and requires no external clock crystal or signal. This oscillator drives both the keypad scan engine and the 32.768 kHz PWM timer clock, eliminating external timing components and reducing system cost and board area.
What happens to the IRQN pin after power-on reset of LM8328TMX/NOPB?
After power-on reset, the IRQN pin (ball E3) is driven low due to the PORIRQ signal. To release it, the host must write 0x01 to the RSTINTCLR register (address 0x84). Until this write occurs, IRQN remains asserted, preventing false interrupt interpretation by the host processor.
Does LM8328TMX/NOPB support wake-up from HALT mode on keypad activity?
Yes. LM8328TMX/NOPB wakes from HALT mode on any keypad event (press or release), I²C bus activity matching its slave address, or external reset. Wake-up latency is under 100 µs, and the device automatically re-enables internal clocks and resumes scanning - enabling responsive UI with minimal power penalty.
LM8328TMX/NOPB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 25-WFBGA, DSBGA
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Applications:
- Mobile Communications
- Interface:
- I2C
- Voltage - Supply:
- 1.62V ~ 1.98V
- Supplier Device Package:
- 25-DSBGA
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
LM8328TMX/NOPB FAQ
1.How can I place an order for LM8328TMX/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM8328TMX/NOPB 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 LM8328TMX/NOPB reliable?
The price and inventory of LM8328TMX/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM8328TMX/NOPB is usually 5 days.
3.What payment methods are accepted for LM8328TMX/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM8328TMX/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM8328TMX/NOPB?
LM8328TMX/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM8328TMX/NOPB 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 LM8328TMX/NOPB?
For technical support, including LM8328TMX/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM8328TMX/NOPB requirements.
6.How does Aetrix verify that LM8328TMX/NOPB is sourced from the original manufacturer or authorized distributors?
All LM8328TMX/NOPB 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 LM8328TMX/NOPB meets industry standards.
7.What is the process for return or replacement of LM8328TMX/NOPB?
All LM8328TMX/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM8328TMX/NOPB, 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 LM8328TMX/NOPB part is unused and in its original packaging.
Return procedure for LM8328TMX/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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