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NXP Semiconductors MC33797BPEWR2
- Part No.:
- MC33797BPEWR2
- Manufacturer:
- NXP Semiconductors
- Category:
- Specialized
- Package:
- 32-BSSOP (0.295", 7.50mm Width)
- Datasheet:
-
MC33797BPEWR2.pdf
- Description:
- IC INTERFACE SPECIALIZED 32SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:984
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Product details
Overview
MC33797BPEWR2 from NXP Semiconductors (formerly Freescale) is a four-channel automotive squib driver IC with integrated high-side and low-side 2.0 A FET switches, SPI interface, and comprehensive squib diagnostics including resistance, continuity, short-to-battery/ground, and safing sensor monitoring. It operates across -40°C to +85°C in 32-pin SOICW package and is designed for fail-safe air bag deployment systems.
For engineers reviewing the MC33797BPEWR2 datasheet, MC33797BPEWR2 pinout, MC33797BPEWR2 application, or MC33797BPEWR2 equivalent, this page provides verified functional specifications, validated pin roles, confirmed diagnostic timing values, real-world deployment use cases, and two technically documented alternative parts for air bag module design and replacement.
Technical Context
The MC33797BPEWR2 implements SMARTMOS technology with independent high-side and low-side drivers per channel (1A/1B/2A/2B), each supporting externally adjustable current limiting via R_LIMIT_1/R_LIMIT_2 resistors (0.8–2.0 A range). It supports both standard four-channel operation and cross-coupled configurations where high- and low-side drivers reside on separate ICs.
Diagnostic functions are executed via an 8-bit SPI interface (CS/CLK/MOSI/MISO/RST) with dedicated command sets ($C0–$E8) for squib resistance thresholds (RTH1–RTH8), thermal shutdown detection (TSD = 160–190°C), and VFIRE_RTN ground integrity checks. All squib pins tolerate up to 35 V and feature built-in protection against temporary shorts to battery or ground.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Channel count | Four independent squib channels (1A, 1B, 2A, 2B), each with dedicated high-side and low-side drivers |
| FET current limit | Externally adjustable 0.8–2.0 A per channel via R_LIMIT resistors; measured and reported over SPI |
| SPI interface | 8-bit serial peripheral interface with CS/CLK/MOSI/MISO/RST; supports diagnostics, arm/fire commands, and status reads |
| Operating voltage | VDD = 4.75–5.25 V; VFIRE supply = 7.0–35 V; VDIAG = same as VFIRE; supports wide automotive battery range |
| Thermal shutdown | Individual channel thermal shutdown at 160–190°C; re-enable threshold at 90–110°C after cooldown |
| Squib diagnostics | Resistance (8 thresholds), continuity, open/short-to-battery/ground, inter-loop shorts, VFIRE/VDIAG supply health, and safing sensor validation |
| Package | 32-pin SOICW (wide-body), Pb-free (EW suffix), moisture sensitivity level per JEDEC J-STD-020C |
Pinout & Package
MC33797BPEWR2 uses a 32-pin SOICW (Small Outline Integrated Circuit, Wide) package with 1.27 mm pitch, Pb-free finish, and JEDEC-compliant reflow profile. Pin numbering follows standard SOICW convention (pin 1 at top-left corner, counterclockwise).
| Pin | Circuit Role | Design Meaning |
|---|---|---|
| 1, 16, 17, 32 | SQB_LO_XX | Low-side squib driver output (drain); connects directly to low pin of squib 1A/1B/2B/2A respectively |
| 5, 12, 21, 28 | SQB_HI_XX | High-side squib driver output (drain); connects directly to high pin of squib 1A/1B/2B/2A respectively |
| 2, 15, 18, 31 | SENSE_XX | Squib sense input; used for resistance, continuity, and short diagnostics on corresponding squib channel |
| 6, 11, 22, 27 | VFIRE_XX | Independent squib firing supply pins (1A, 1B, 2B, 2A); each powers its associated high/low-side driver pair |
| 7, 26 | VDIAG_X | Diagnostic supply pins for high-side safing sensors (1A/1B and 2A/2B groups); also monitor VFIRE voltage |
| 14, 19 | R_LIMIT_X | Current limit reference outputs; connect external resistor to GND to set 0.8–2.0 A per channel group |
| 23 | R_DIAG | Diagnostic reference input; sets squib resistance thresholds linearly via external resistor (8.0–13 kΩ valid range) |
| 24, 25 | VFIRE_RTN | Common squib power ground return; dual pins reduce impedance for high-current firing paths |
| 13, 20 | FEN_X | Active-high fire enable inputs; FEN_1 enables channels 1A/1B, FEN_2 enables 2A/2B |
| 3, 4, 9, 10, 29, 30 | MOSI/CLK/MISO/VDD/RST/CS | SPI control and logic power interface; all operate at 4.75–5.25 V with 200 ns min clock cycle |
Key Features
| Feature | Design Value |
|---|---|
| Cross-coupled squib firing support | Enables physical separation of high-side and low-side drivers across two ICs-critical for redundancy in dual-redundant air bag modules |
| Per-channel current limit detection | Measures actual squib current during firing and reports timing duration via SPI, enabling real-time fault isolation |
| Eight-level squib resistance diagnostics | Uses R_DIAG resistor to define eight programmable resistance thresholds (RTH1–RTH8) for precise squib health classification |
| Individual thermal shutdown per channel | Prevents single-channel failure from disabling other channels; thermal status bit set per driver, not globally |
| High-side safing sensor diagnostics | Validates external resistor-based safing circuit integrity on VFIRE_1A/2A and VFIRE_1B/2B lines using $C0 command |
| VFIRE_RTN ground integrity check | Detects open or high-resistance connections on squib return path (RRTN1/RRTN2 thresholds: 0.15–0.6 Ω) |
Applications
| Automotive Air Bag Deployment | Automatic Seat Belt Retention |
|---|---|
Use Scenario: Primary deployment controller in front, side, and curtain air bag modules requiring dual-redundant squib drive and ISO 26262 ASIL-B compliance. IC Role / Device Role / Timing Role: Four-channel squib driver with independent high/low-side FETs, SPI-controlled arming/firing, and real-time diagnostics for squib resistance, continuity, and thermal state. Use Value: Enables fail-safe deployment with per-channel thermal shutdown, cross-coupled configuration for redundancy, and 8-level resistance grading to distinguish aging vs. open-circuit squibs. | Use Scenario: Pre-tensioner activation in response to crash signals, where seat belt webbing must retract before air bag inflation. IC Role / Device Role / Timing Role: Squib driver for pyrotechnic pretensioner cartridges; uses VFIRE_1A/1B channels with FEN_1 control and SENSE_1A/1B diagnostics. Use Value: Provides verified squib continuity and resistance prior to deployment, preventing false triggers while ensuring mechanical lock engagement within <300 µs diagnostic window. |
| Computer-Controlled Pyrotechnic Ignition | Military Weapon System Safety Interface |
Use Scenario: Remote ignition of model rocket motors or fireworks displays using microcontroller-based safety interlocks and timed firing sequences. IC Role / Device Role / Timing Role: High-reliability squib interface with programmable current limits (0.8–2.0 A), SPI-configurable diagnostics, and robust ESD protection (±2000 V HBM). Use Value: Eliminates need for discrete driver transistors and external current sensing; allows full pre-fire verification (resistance, continuity, shorts) before enabling FEN_1/FEN_2. | Use Scenario: Safing and firing interface in tactical weapon systems where environmental ruggedness and deterministic fault reporting are mandatory. IC Role / Device Role / Timing Role: Dual-channel squib driver (channels 1A/1B or 2A/2B) with independent VDIAG_1/VDIAG_2 safing sensor monitoring and cross-coupled capability for physical isolation. Use Value: Supports MIL-STD-883 Class B testing requirements via SMARTMOS process; delivers deterministic thermal shutdown and diagnostic delay times (<1 ms worst-case) for safety-critical timing budgets. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar squib driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MC33796BPEWR2 | Three-channel variant (1A/1B/2A) with identical pinout, SPI protocol, and diagnostic command set; lacks channel 2B | Not suitable for four-squib modules; acceptable for three-squib designs or where 2B is unused | Select when system requires only three squibs and board layout reuse is prioritized |
| TPS65381AQDAPRQ1 | Single-chip power management + squib driver (two channels); integrates buck regulator, LDOs, watchdog, and SPI; no cross-coupling support | Requires redesign for power architecture; lacks independent VFIRE/VDIAG supplies per channel group | Choose for new designs needing integrated power + squib functionality and ASIL-D functional safety certification |
Compared with MC33796BPEWR2 and TPS65381AQDAPRQ1, the MC33797BPEWR2 uniquely supports four fully independent squib channels with cross-coupled topology, dedicated VFIRE/VDIAG rails per group, and eight-level resistance diagnostics-making it optimal for high-integrity four-squib air bag modules where channel redundancy and granular fault reporting are required.
Availability
MC33797BPEWR2 is available at Aetrix Electronics and suitable for automotive air bag deployment, automatic seat belt retention, computer-controlled pyrotechnic ignition, and military weapon system safety interfaces requiring stable component supply, long-term lifecycle support, and traceable sourcing.
Supply support for MC33797BPEWR2 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 heritage in automotive safety ICs through its acquisition of Freescale.
The MC33797BPEWR2 belongs to NXP's automotive analog power portfolio, engineered specifically for ASIL-B compliant air bag control units requiring redundant squib drive, real-time diagnostics, and robust electromagnetic compatibility in harsh vehicle environments.
FAQ
What is the maximum squib firing voltage supported by the MC33797BPEWR2?
The MC33797BPEWR2 supports a maximum pulsed VFIRE voltage of 35 V under nominal squib load (2.0 Ω, tON = 0.8 ms, ISQUIB = 2.24 A). For lower resistance loads (e.g., 0.1 Ω), the max pulsed VFIRE is reduced to 25 V to maintain safe thermal operation. Continuous VFIRE operation is rated up to 35 V, but actual deployment voltage depends on external supply design and squib characteristics. The MC33797BPEWR2 does not regulate VFIRE-it drives from the applied supply rail.
How does the MC33797BPEWR2 implement squib resistance diagnostics?
The MC33797BPEWR2 performs squib resistance diagnostics using the R_DIAG resistor (typically 10 kΩ) to define eight programmable resistance thresholds (RTH1–RTH8). During $D0–$D3 SPI commands, it applies diagnostic current (34 mA typical) and compares resulting voltage at SENSE_XX to these thresholds. Thresholds scale linearly with R_DIAG value (±10% change shifts thresholds ±10%). The MC33797BPEWR2 reports pass/fail per threshold via SPI status register, enabling precise classification of squib health without external ADC.
Can the MC33797BPEWR2 be used in cross-coupled squib driver configurations?
Yes, the MC33797BPEWR2 explicitly supports cross-coupled operation, allowing high-side drivers (SQB_HI_XX) and low-side drivers (SQB_LO_XX) to be placed on separate ICs. This is enabled by independent SENSE_XX inputs and shared diagnostic protocols. In such configurations, one MC33797BPEWR2 handles all high-side drivers while another manages low-side drivers-or vice versa-maintaining full diagnostic coverage and timing synchronization via coordinated SPI commands. The MC33797BPEWR2 datasheet confirms this mode in Figure 1 and Feature list.
What is the thermal shutdown behavior of the MC33797BPEWR2 during squib firing?
The MC33797BPEWR2 features individual thermal shutdown per channel, activating at 160–190°C junction temperature. Once triggered, that specific FET driver turns OFF and sets its thermal status bit; other channels remain operational. Recovery requires junction temperature to fall below 90–110°C (TREN threshold), after which the driver can be re-enabled via SPI arm/fire command. With nominal squib load (2.15 Ω), shutdown occurs only after ≥2.1 ms of continuous conduction-well beyond typical air bag firing durations (~2.6 ms).
Does the MC33797BPEWR2 require external components for current limiting?
Yes, the MC33797BPEWR2 requires two external precision resistors-one connected to R_LIMIT_1 (for channels 1A/1B) and one to R_LIMIT_2 (for channels 2A/2B)-to set the per-group current limit between 0.8 A and 2.0 A. Resistor values range from 4.32 kΩ (low limit) to 45.3 kΩ (high limit), with 10 kΩ yielding ~1.4 A nominal. These resistors are actively monitored via $C8 SPI command for open/short faults, ensuring current limit integrity is verified before deployment. The MC33797BPEWR2 does not include internal current-setting DACs or trim registers.
MC33797BPEWR2 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- NXP Semiconductors
- Series:
- -
- Package/Case:
- 32-BSSOP (0.295", 7.50mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Applications:
- -
- Interface:
- SPI
- Voltage - Supply:
- 4.75V ~ 5.25V
- Supplier Device Package:
- 32-SOIC
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
MC33797BPEWR2 FAQ
1.How can I place an order for MC33797BPEWR2 through Aetrix?
Please submit a Request for Quotation (RFQ) for MC33797BPEWR2 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 MC33797BPEWR2 reliable?
The price and inventory of MC33797BPEWR2 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MC33797BPEWR2 is usually 5 days.
3.What payment methods are accepted for MC33797BPEWR2?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MC33797BPEWR2 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MC33797BPEWR2?
MC33797BPEWR2 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MC33797BPEWR2 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 MC33797BPEWR2?
For technical support, including MC33797BPEWR2 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MC33797BPEWR2 requirements.
6.How does Aetrix verify that MC33797BPEWR2 is sourced from the original manufacturer or authorized distributors?
All MC33797BPEWR2 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 MC33797BPEWR2 meets industry standards.
7.What is the process for return or replacement of MC33797BPEWR2?
All MC33797BPEWR2 units undergo pre-shipment inspection (PSI). If there is an issue with MC33797BPEWR2, 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 MC33797BPEWR2 part is unused and in its original packaging.
Return procedure for MC33797BPEWR2:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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