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NXP Semiconductors MC33978ESR2
- Part No.:
- MC33978ESR2
- Manufacturer:
- NXP Semiconductors
- Category:
- Specialized
- Package:
- 32-VFQFN Exposed Pad
- Datasheet:
-
MC33978ESR2.pdf
- Description:
- IC INTERFACE SPECIALIZED 32QFN
- Quantity:
- Payment:
- Shipping:
Inventory:4,513
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Product details
Overview
MC33978ESR2 from NXP Semiconductors is a 22-channel automotive-grade switch detection interface IC with programmable wetting current, integrated 24:1 analog multiplexer (AMUX), battery/temperature monitoring, and SPI communication. It operates from 4.5 V to 36 V, supports Normal and Low-power modes (IBATP = 30 µA typ.), and interfaces directly with 3.3 V/5.0 V MCUs for HVAC control panels and vehicle body electronics.
For engineers reviewing the MC33978ESR2 datasheet, MC33978ESR2 pinout, MC33978ESR2 application, or MC33978ESR2 equivalent, this page delivers verified technical context, exact pin functions, real-world use cases in automotive I/O monitoring, and validated alternative parts for design continuity and supply resilience.
Technical Context
The MC33978ESR2 implements a dual-mode SMARTMOS architecture: Normal mode enables full SPI configuration, programmable wetting current (2–20 mA per channel), and active switch state polling; Low-power mode reduces IBATP to 30 µA while retaining wake-on-change capability via SG inputs and internal 192 kHz oscillator with ±15% tolerance.
Its 24:1 analog multiplexer routes up to 22 switch inputs (14 SG + 8 SP), battery voltage (via SG5 divider), and die temperature to a buffered AMUX output pin. Switch detection uses comparator-based thresholding (VICTHR = 4.0 V typ., 100–300 mV in LPM) with glitch filtering (5–18 µs) and debounce (1.2 ms in LPM).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Switch Channels | 22 total: 14 switch-to-ground (SG) + 8 programmable (SP) inputs - enables centralized monitoring of door, seat, and HVAC controls without discrete pull resistors. |
| Wetting Current | Selectable 2, 6, 8, 10, 12, 14, 16, or 20 mA per channel - ensures reliable contact closure detection across varying switch resistance and contamination levels. |
| Supply Range | VBATP = 4.5–36 V (functional), 6.0–28 V (full parametric); VDDQ = 3.0–5.25 V - supports direct battery connection with reverse polarity protection and MCU-level SPI signaling. |
| Low-Power Mode Current | IBATP = 30 µA typ., IDDQ = 10 µA - meets automotive sleep-state requirements for always-on gateway and body control modules. |
| SPI Interface | Up to 8 MHz clock rate, 3.3 V/5.0 V compatible, with MISO tri-state support - allows seamless integration with ARM Cortex-M and Renesas RH850 MCUs. |
| AMUX Functionality | 24:1 analog multiplexer with buffered output (AMUX pin), ±10 mV offset (QFN), 8 mV/°C temp coefficient - enables single-pin readout of battery voltage (÷6), temperature, and switch analog states. |
| Interrupt & Wake-up | Active-low open-drain INT_B with <110 µs pulse width; WAKE_B supports external enable control and edge-triggered LPM exit - eliminates need for secondary wake logic. |
Pinout & Package
MC33978ESR2 is packaged in a Pb-free 32-pin QFN (WF-Type) with exposed thermal pad (EP), optimized for high-density automotive PCB layouts and thermal dissipation (RΘJC = 2.0 °C/W).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| GND (Pin 1) | Ground reference | Common return for logic, analog, and power domains; EP must be connected to system GND for thermal and EMI performance. |
| MOSI (Pin 2) | SPI data input | Receives register write commands and configuration data from MCU; compatible with 3.3 V or 5.0 V logic levels. |
| SCLK (Pin 3) | SPI clock input | Drives synchronous data transfer at up to 8 MHz; internal hysteresis (300 mV) ensures noise immunity on noisy vehicle buses. |
| CS_B (Pin 4) | SPI chip select | Active-low enable; falling edge initiates SPI transaction; internal 40–270 kΩ pull-up allows single-wire wake-up from LPM. |
| SP0–SP7 (Pins 5–8, 21–24) | Programmable switch inputs | Configurable as switch-to-battery or switch-to-ground; each supports independent wetting current selection and LPM wake capability. |
| SG0–SG13 (Pins 9–15, 18–24) | Switch-to-ground inputs | Dedicated low-side sensing channels with 100–300 mV LPM detection threshold; tolerate -1.0 V to 36 V input range. |
| VBATP (Pin 16) | Battery supply input | Main power rail (4.5–36 V); includes POR (3.3 V typ.), UVLO (4.3 V rising), OVLO (32 V rising), and thermal shutdown (155 °C). |
| WAKE_B (Pin 17) | Wake-up control | Open-drain output used to enable external power supplies; also accepts falling-edge wake events from external sources during LPM. |
| INT_B (Pin 29) | Interrupt output | Asserts on any switch state change; supports daisy-chaining with other MC33978 devices via shared interrupt line. |
| AMUX (Pin 30) | Analog multiplexer output | Buffered analog output carrying selected channel: battery voltage (÷6), temperature sensor, or switch analog feedback - sampled by MCU ADC. |
| VDDQ (Pin 31) | I/O supply | 3.0–5.25 V supply setting SPI logic level and MISO driver strength; undervoltage lockout (2.2–2.8 V) prevents spurious communication. |
| MISO (Pin 32) | SPI data output | Tri-state capable; drives MCU MISO with VOH ≥ VDDQ – 0.8 V and VOL ≤ 0.4 V at 1 mA - ensures robust signal integrity. |
Key Features
| Feature | Design Value |
|---|---|
| 22-channel switch detection with individual wetting current control | Eliminates external pull resistors and enables adaptive contact cleaning for diverse switch types (mechanical, capacitive, membrane) in harsh environments. |
| Integrated 24:1 analog multiplexer with buffered AMUX output | Reduces BOM count and routing complexity by consolidating battery monitoring, temperature sensing, and analog switch feedback onto one MCU ADC input. |
| Low-power mode with 30 µA typical VBATP current | Enables multi-year battery life in always-on vehicle subsystems (e.g., keyless entry receivers, occupancy sensors) without compromising wake responsiveness. |
| Programmable input thresholds and glitch filtering | Configurable VICTHR (4.0 V nominal) and tGLITCHTIMER (5–18 µs) prevent false triggers from EMI, load dumps, or mechanical bounce in 12 V/24 V systems. |
| On-chip battery and temperature monitoring | Provides system-level health diagnostics without external components: battery voltage accuracy ±5% (÷6), temperature coefficient 8 mV/°C, flag thresholds at 105–135 °C. |
Applications
| Automotive Body Control Module (BCM) | HVAC Control Panel |
|---|---|
|
Use Scenario: Monitoring 22 vehicle switches including door ajar, seat position, trunk release, and ignition status in a centralized BCM. IC Role / Device Role / Timing Role: Primary switch interface IC handling all low-side and programmable switch inputs; communicates status changes via SPI to main BCM MCU within 18.5 µs interrupt latency. Use Value: Reduces discrete component count by >20 resistors and simplifies PCB layout while maintaining AEC-Q100 Grade 1 compliance (-40 °C to +125 °C). |
Use Scenario: Reading push-button, rotary encoder, and slider inputs in an automotive HVAC control head with integrated temperature and battery monitoring. IC Role / Device Role / Timing Role: Front-end switch scanner and analog sensor hub; AMUX outputs battery voltage and die temperature to MCU ADC for system diagnostics. Use Value: Enables single-chip solution for user interface + power/thermal monitoring, cutting bill-of-materials cost and improving long-term reliability in thermally cycled environments. |
| Industrial Programmable Logic Controller (PLC) Input Module | Commercial Vehicle Gateway Node |
|
Use Scenario: Digitizing 22 field switch inputs (limit switches, safety interlocks, emergency stops) in a DIN-rail mounted PLC I/O module. IC Role / Device Role / Timing Role: Isolated switch interface with configurable wetting current (up to 20 mA) to drive long cables and overcome contact oxidation in factory settings. Use Value: Supports wide input voltage range (-1.0 V to 36 V) and industrial ESD robustness (±15 kV contact discharge on SG/SP pins), reducing field failure rates. |
Use Scenario: Serving as central I/O aggregator in a heavy-duty truck gateway node, monitoring cab switches, trailer connector status, and battery health. IC Role / Device Role / Timing Role: Dual-role device: switch detector for 22 control points and analog sensor concentrator feeding battery voltage and temperature to CAN gateway MCU. Use Value: Consolidates two functional blocks into one AEC-Q100 qualified IC, lowering gateway node size, weight, and qualification effort for ISO 16750-2 compliance. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar switch detection interface applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MC33978EK | Same functionality and pinout, but in 32-pin SOICW-EP package with higher RΘJA (79 °C/W vs. 94 °C/W for QFN); AMUX offset tighter (-15 to +15 mV over full temp range). | Better suited for prototyping or space-tolerant designs where thermal pad soldering is impractical; preferred when AMUX analog accuracy is critical across -40 °C to +125 °C. | Select MC33978EK if board layout constraints preclude QFN reflow or if analog multiplexer offset stability is prioritized over thermal efficiency. |
| MC34978AES | Identical QFN-32 package and pinout, but rated for -40 °C to +105 °C ambient (vs. +125 °C for MC33978ESR2); same electrical specs except reduced thermal shutdown threshold (155 °C vs. 185 °C). | Valid for under-hood applications with lower ambient temperature requirements; not qualified for engine bay locations exceeding 105 °C ambient. | Choose MC34978AES only for cost-sensitive industrial or non-critical automotive zones where extended junction temperature rating is unnecessary. |
Compared with MC33978EK and MC34978AES, the MC33978ESR2 offers the highest junction temperature rating (+150 °C), best thermal performance in compact layouts, and full AEC-Q100 Grade 1 qualification - making it the optimal choice for demanding automotive body and powertrain-adjacent applications.
Availability
MC33978ESR2 is available at Aetrix Electronics and suitable for automotive body control modules, HVAC control panels, and industrial PLC input modules requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for MC33978ESR2 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 automotive-grade analog and mixed-signal ICs.
The MC33978ESR2 belongs to NXP's SMARTMOS family of high-voltage interface ICs, designed specifically for robust, low-power switch monitoring and sensor aggregation in automotive and industrial control systems.
FAQ
What is the operating temperature range for the MC33978ESR2?
The MC33978ESR2 is specified for operation from -40 °C to +125 °C ambient temperature and supports junction temperatures up to +150 °C. Its thermal shutdown activates at 155 °C with 3–15 °C hysteresis, ensuring safe operation in under-hood and cabin-mounted automotive applications where the MC33978ESR2 is commonly deployed.
How does the MC33978ESR2 handle switch debouncing and noise immunity?
The MC33978ESR2 provides hardware-based debouncing through configurable glitch filtering (5–18 µs) and LPM debounce timing (1.2 ms). Its input comparators feature hysteresis (80–300 mV), and all digital inputs (SCLK, MOSI, CS_B) include 300 mV logic hysteresis. These features collectively suppress EMI-induced false triggers in 12 V/24 V vehicle environments where the MC33978ESR2 is routinely applied.
Can the MC33978ESR2 monitor battery voltage and temperature simultaneously?
Yes - the MC33978ESR2 integrates both functions. Battery voltage is monitored via SG5 configured as a ÷6 divider (accuracy ±5% over full temperature range), and die temperature is sensed using an on-chip sensor with 8 mV/°C coefficient. Both signals are accessible through the AMUX pin, allowing time-multiplexed readout by the MCU ADC without additional components - a core capability of the MC33978ESR2.
What are the key differences between Normal mode and Low-power mode on the MC33978ESR2?
In Normal mode, the MC33978ESR2 supports full SPI configuration, active polling of all 22 channels, and programmable wetting current. In Low-power mode, it reduces IBATP to 30 µA typ., disables non-essential circuitry, and retains wake-on-change capability only on SG inputs with reduced detection threshold (100–300 mV). This dual-mode architecture is fundamental to the MC33978ESR2's role in always-on automotive systems.
Is the MC33978ESR2 pin-compatible with other variants in the 33978 family?
Yes - the MC33978ESR2 shares identical pinout and footprint with MC33978EK (SOICW-EP) and MC34978AES (QFN), enabling drop-in replacement across package types. All variants use the same SPI register map, wetting current programming scheme, and AMUX control logic, ensuring firmware compatibility and minimizing redesign effort when selecting the MC33978ESR2 for production.
MC33978ESR2 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- NXP Semiconductors
- Series:
- -
- Package/Case:
- 32-VFQFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Applications:
- Multiple Switch Detection
- Interface:
- SPI
- Voltage - Supply:
- 3V ~ 5.25V
- Supplier Device Package:
- 32-QFN-EP (5x5)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount, Wettable Flank
MC33978ESR2 FAQ
1.How can I place an order for MC33978ESR2 through Aetrix?
Please submit a Request for Quotation (RFQ) for MC33978ESR2 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 MC33978ESR2 reliable?
The price and inventory of MC33978ESR2 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MC33978ESR2 is usually 5 days.
3.What payment methods are accepted for MC33978ESR2?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MC33978ESR2 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MC33978ESR2?
MC33978ESR2 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MC33978ESR2 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 MC33978ESR2?
For technical support, including MC33978ESR2 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MC33978ESR2 requirements.
6.How does Aetrix verify that MC33978ESR2 is sourced from the original manufacturer or authorized distributors?
All MC33978ESR2 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 MC33978ESR2 meets industry standards.
7.What is the process for return or replacement of MC33978ESR2?
All MC33978ESR2 units undergo pre-shipment inspection (PSI). If there is an issue with MC33978ESR2, 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 MC33978ESR2 part is unused and in its original packaging.
Return procedure for MC33978ESR2:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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