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Texas Instruments LM2642MTCX
- Part No.:
- LM2642MTCX
- Manufacturer:
- Texas Instruments
- Category:
- Power Management - Specialized
- Package:
- 28-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
LM2642MTCX.pdf
- Description:
- IC CTLR SW SYNC STPDN 28-TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:3,894
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Product details
Overview
LM2642MTCX from Texas Instruments is a two-phase synchronous step-down switching controller IC that regulates two independent 1.3V–27V outputs from a 4.5V–30V input, operating at 300kHz with 180° phase shift to reduce input ripple RMS current-used in high-efficiency dual-rail power supplies for embedded computing and gaming systems.
For engineers reviewing the LM2642MTCX datasheet, LM2642MTCX pinout, LM2642MTCX application, or LM2642MTCX equivalent, this page delivers verified technical context, real-world design meaning of specifications, validated 28-pin TSSOP pin functions, confirmed alternative controllers for dual-buck topologies, and supply-chain support details for volume procurement and BOM continuity.
Technical Context
The LM2642MTCX implements dual independent current-mode PWM controllers with fixed 300kHz oscillator frequency, 180° inter-channel phase alignment, and separate soft-start/enable pins (ON/SS1, ON/SS2) enabling sequential or parallel startup configurations. Each channel features cycle-by-cycle current limiting via Kelvin-sense inputs (KS1/RSNS1, KS2/RSNS2) and adjustable ILIMx threshold setting.
It integrates a 5V LDO (VLIN5) for internal bias and bootstrap gate-drive supplies, supports external MOSFET drive via HDRVx/LDRVx outputs with specified on-resistance (≤535Ω), and provides comprehensive protection including latch-type OVP (107–122% VOUT), UVP with UV_DELAY programmable delay, thermal shutdown, and PGOOD1 monitoring for Channel 1 only.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4.5V to 30V - supports wide-input industrial and automotive DC rails without pre-regulation. |
| Output Voltage Range | 1.3V to VIN − duty-cycle loss - enables flexible rail generation (e.g., 1.8V, 3.3V, 5V, 12V) using standard feedback dividers. |
| Switching Frequency | 260–340kHz (typ. 300kHz) - balances efficiency, EMI, and inductor size for mid-power applications (≤14A per channel). |
| Line/Load Regulation | ±0.04% (typ.) - ensures stable output under varying input and load conditions without external compensation tuning. |
| Shutdown Current | 37µA - enables ultra-low quiescent power in standby mode while retaining VLIN5 bias for fast wake-up. |
| PGOOD1 Window | 90.3% to 97.0% of nominal VOUT - provides precise power-good assertion with hysteresis for reliable system sequencing. |
| UV Delay Threshold | 2.3V (typ.) - sets UVP latch timing via external capacitor; grounding UV_DELAY disables UVP entirely. |
Pinout & Package
LM2642MTCX is housed in a thermally enhanced 28-lead TSSOP package (4.4mm × 9.7mm, 0.65mm pitch) with exposed thermal pad for improved power dissipation in high-current designs.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| KS1, RSNS1 / KS2, RSNS2 | Kelvin current sense inputs | Enable accurate high-side FET Rds(on) or external resistor sensing with minimal PCB trace impedance error. |
| ILIM1, ILIM2 | Current limit threshold set | Sink 10µA to define overcurrent trip point independently per channel using resistor-to-VIN connection. |
| ON/SS1, ON/SS2 | Channel enable & soft-start control | Open-collector compatible; capacitor-based ramp controls monotonic VOUT rise and prevents inrush overshoot. |
| PGOOD1 | Channel 1 power-good monitor | Open-drain output latched low during OVP/UVP on either channel or when Ch1 drops below 90.3% VOUT. |
| VIN, PGND, SGND | Power input & ground returns | Separate power (PGND) and signal (SGND) grounds minimize noise coupling into sensitive analog control loops. |
| HDRV1/LDRV1, HDRV2/LDRV2 | High/low-side gate drivers | Drive external N-channel MOSFETs with 0.5A source / 0.8–1.1A sink capability and defined on-resistance. |
| VLIN5 | Internal 5V LDO output | Supplies internal logic and bootstrap circuitry; requires ≥4.7µF bypass capacitor for stability under dynamic load. |
Key Features
| Feature | Design Value |
|---|---|
| 180° out-of-phase operation | Reduces input capacitor RMS current by ~70% vs. in-phase dual buck, allowing smaller bulk capacitance and lower ESR cost. |
| Independent soft-start control | Enables configurable startup sequencing (e.g., PGOOD1 → ON/SS2) or simultaneous ramp for balanced load sharing. |
| Configurable single-output parallel mode | Both channels drive same inductor via shared SW node-doubles current capability while maintaining regulation accuracy. |
| Output capacitor self-discharge | Embedded 480Ω discharge MOSFET on each SWx pin safely bleeds stored energy during fault or shutdown. |
| Thermal shutdown & UVLO | Protects against sustained overload or low-input conditions; UVLO triggers at 3.6–4.4V rising edge to prevent brownout instability. |
Applications
| Server CPU Core Power | Gaming GPU VRM |
|---|---|
|
Use Scenario: Dual-rail core voltage (VDD/VDDQ) delivery for multi-core x86 processors requiring tight transient response and low noise. IC Role / Device Role / Timing Role: Two-phase synchronous buck controller managing discrete high-side/lower-side MOSFETs per phase with interleaved timing. Use Value: 180° phase shift cuts input ripple current, reducing required bulk capacitance by >50% and easing layout constraints near CPU socket. |
Use Scenario: High-current GPU core and memory rail generation in desktop graphics cards with strict thermal and efficiency targets. IC Role / Device Role / Timing Role: Dual-channel controller driving paralleled FETs per phase, supporting up to 28A total with independent current limiting. Use Value: Adjustable ILIMx thresholds allow precise per-phase current limiting to match asymmetric FET layouts and prevent thermal runaway. |
| Set-Top Box SoC Supply | Industrial Embedded Controller |
|
Use Scenario: Compact dual-output power supply for ARM-based media SoCs requiring 1.1V core and 3.3V I/O rails from 12V DC input. IC Role / Device Role / Timing Role: Primary controller implementing soft-start sequencing (Ch1→Ch2 via PGOOD1) and UV_DELAY-based brownout hold-off. Use Value: 37µA shutdown current and VLIN5 retention enable rapid wake-from-standby without full re-initialization. |
Use Scenario: Reliable dual-rail power for PLC CPU modules operating in extended temperature (-40°C to +125°C) industrial environments. IC Role / Device Role / Timing Role: Robust controller with latch-type OVP/UVP, thermal shutdown, and Kelvin-sense current monitoring for field reliability. Use Value: ±0.04% line/load regulation ensures consistent rail accuracy across wide input range and ambient temperature swings. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual-phase synchronous buck controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TPS54620RGYT | Integrated FETs (30V, 6A/channel), fixed 350kHz freq, no UV_DELAY pin, PGOOD per channel. | Better for space-constrained designs needing integrated power stage; lacks programmable UVP delay and dual PGOOD. | Select when board area is critical and discrete FETs are undesirable; verify thermal limits at full load. |
| ISL6269CRZ | Two-phase controller with DVID interface, 500kHz max freq, integrated MOSFET drivers, no VLIN5 LDO. | Targeted at mobile CPU VRMs with dynamic voltage ID; requires external 5V bias and offers finer frequency control. | Prefer for laptop-style adaptive voltage scaling; avoid if VLIN5-derived bootstrap supply is required. |
Compared with TPS54620RGYT and ISL6269CRZ, LM2642MTCX uniquely combines external FET flexibility, programmable UV_DELAY timing, and self-contained VLIN5 bias-making it optimal for industrial and embedded systems where discrete power stage selection, robust brownout handling, and simplified gate-drive supply are prioritized over integration density.
Availability
LM2642MTCX is available at Aetrix Electronics and suitable for embedded computer systems, high-end gaming platforms, and set-top box power supplies requiring stable component supply across long production lifecycles.
Supply support for LM2642MTCX 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 leader specializing in analog, embedded processing, and power management ICs, with decades of expertise in high-reliability power conversion solutions.
The LM2642 product line delivers dual-phase synchronous buck controllers for mid-to-high power applications demanding precision regulation, robust protection, and flexible discrete FET implementation-designed for industrial, computing, and consumer electronics power subsystems.
FAQ
What is the maximum duty cycle supported by LM2642MTCX?
The LM2642MTCX supports a maximum on-duty cycle of 96–98% (typical 98%) across its operating temperature range. This allows regulation down to output voltages as low as 1.3V from a 30V input, making it suitable for high-step-down applications such as 1.8V or 1.1V core supplies. The actual achievable duty cycle depends on gate driver timing margins and external FET characteristics, but the internal control loop guarantees stable operation up to the specified limit. LM2642MTCX maintains this performance across -40°C to +125°C junction temperatures.
Does LM2642MTCX support parallel operation of both channels for single-output high-current applications?
Yes, LM2642MTCX explicitly supports configurable parallel operation where both channels drive the same output in-phase, doubling current capability while maintaining regulation accuracy. Figure 3 in the official datasheet shows this configuration with shared inductor and synchronized gate drive. The device retains independent current limiting and soft-start control, enabling safe current sharing. LM2642MTCX achieves this without external synchronization circuitry due to its internal 180° phase generator and dedicated parallel-mode logic.
How does the UV_DELAY pin function in LM2642MTCX, and what happens if it's left unconnected?
The UV_DELAY pin on LM2642MTCX connects to an external capacitor that sets the time delay before UVP latching occurs during an output under-voltage event. A 5µA internal current source charges the capacitor; at 2.3V (typ.), both channels latch off. If left floating, leakage paths may cause unpredictable timing or false triggering. Connecting UV_DELAY directly to ground disables UVP entirely. LM2642MTCX requires explicit capacitor sizing (e.g., 100nF = ~46ms delay) for deterministic brownout response-no default behavior exists for open-circuit.
Can LM2642MTCX operate with only one channel enabled while the other remains inactive?
Yes, LM2642MTCX supports independent channel enable/disable via ON/SS1 and ON/SS2 pins. Pulling ON/SS1 below 1.2V disables Channel 1 while Channel 2 remains fully functional if ON/SS2 is high, and vice versa. Both channels can be active, single-channel active, or fully shut down. In single-channel mode, LM2642MTCX maintains full regulation, current limiting, and protection features for the active channel-including PGOOD1 monitoring and VLIN5 LDO operation. This flexibility makes LM2642MTCX suitable for scalable power architectures.
What is the purpose of the KS1/RSNS1 and KS2/RSNS2 pins on LM2642MTCX?
The KS1/RSNS1 and KS2/RSNS2 pins on LM2642MTCX provide Kelvin connections for accurate high-side current sensing-either across the Rds(on) of the upper MOSFET or across an external current-sense resistor. KSx is the positive sense input; RSNSx is the negative sense input. This four-terminal measurement rejects PCB trace resistance errors, ensuring precise cycle-by-cycle current limiting even under high di/dt conditions. LM2642MTCX uses these inputs to compare sensed voltage against the ILIMx-set threshold, delivering robust overcurrent protection independent of layout parasitics.
LM2642MTCX Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 28-TSSOP (0.173", 4.40mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Applications:
- Embedded systems, Console/Set-Top boxes
- Current - Supply:
- 1mA
- Voltage - Supply:
- 4.5V ~ 30V
- Operating Temperature:
- -40°C ~ 125°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 28-TSSOP
LM2642MTCX FAQ
1.How can I place an order for LM2642MTCX through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2642MTCX 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 LM2642MTCX reliable?
The price and inventory of LM2642MTCX are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM2642MTCX is usually 5 days.
3.What payment methods are accepted for LM2642MTCX?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2642MTCX transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2642MTCX?
LM2642MTCX orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2642MTCX 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 LM2642MTCX?
For technical support, including LM2642MTCX datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2642MTCX requirements.
6.How does Aetrix verify that LM2642MTCX is sourced from the original manufacturer or authorized distributors?
All LM2642MTCX 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 LM2642MTCX meets industry standards.
7.What is the process for return or replacement of LM2642MTCX?
All LM2642MTCX units undergo pre-shipment inspection (PSI). If there is an issue with LM2642MTCX, 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 LM2642MTCX part is unused and in its original packaging.
Return procedure for LM2642MTCX:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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