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Renesas EL7551CUZ
- Part No.:
- EL7551CUZ
- Manufacturer:
- Renesas
- Package:
- 16-SSOP (0.154", 3.90mm Width)
- Datasheet:
-
EL7551CUZ.pdf
- Description:
- IC REG BUCK ADJ 1A 16QSOP
- Quantity:
- Payment:
- Shipping:
Inventory:2,425
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Product details
Overview
EL7551CUZ from Intersil is a monolithic synchronous step-down DC/DC regulator delivering 1A continuous output current with adjustable output voltage from 1.0V to 3.8V, operating at 4.5V–5.5V input, up to 95% efficiency, and constant-frequency PWM control for DSP/CPU core supplies in portable equipment.
For engineers reviewing the EL7551CUZ datasheet, EL7551CUZ pinout, EL7551CUZ application, or EL7551CUZ equivalent, key selection criteria include its integrated NMOS FETs (45–95 mΩ RDS(on)), cycle-by-cycle current limiting, ±0.5% load/line regulation, internal soft start, and RoHS-compliant 16-pin QSOP package.
Technical Context
The EL7551CUZ implements current-mode PWM control using patented on-chip resistorless current sensing, enabling precise cycle-by-cycle current limiting and fast transient response. Its oscillator supports external synchronization and adjustable frequency up to 1.2MHz via COSC capacitor.
It integrates high-side and low-side NMOS power FETs with bootstrapped high-side gate drive (VHI), internal thermal shutdown (135°C trip), under-voltage lockout (4.0V turn-on), and precision 1.26V bandgap reference with ±50 ppm/°C tempco.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Current | 1A continuous - supports full-load operation in CPU/DSP core rails without external current boosting. |
| Input Voltage Range | 4.5V to 5.5V - matches standard 5V rail systems with margin for ripple and drop. |
| Output Voltage Range | 1.0V to 3.8V adjustable - covers logic I/O, GTL+, and low-voltage core supplies via FB divider. |
| Efficiency | Up to 95% - minimizes thermal dissipation and extends battery life in portable designs. |
| Reference Accuracy | ±0.5% over line/load - ensures tight output regulation critical for sensitive digital loads. |
| Switching Frequency | Adjustable up to 1.2MHz - enables compact magnetics and faster transient response. |
| Thermal Protection | 135°C trip with 20°C hysteresis - prevents latch-up and enables safe recovery after overload. |
Pinout & Package
EL7551CUZ is housed in a Pb-free 16-pin QSOP package (MDP0040), with exposed PGND pins (4, 5, 9, 16) for thermal and power integrity, and dedicated SGND (Pin 1) for noise-sensitive analog circuitry.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (SGND) | Signal ground reference | Isolated return for feedback, reference, and oscillator circuits to prevent switching noise coupling. |
| 2 (COSC) | Oscillator timing node | Connects external capacitor to set switching frequency; supports sync input for system clock alignment. |
| 3 (VDD) | Control circuit supply | Powers internal logic and reference; requires local 0.1µF bypass close to pin. |
| 4,5,9,16 (PGND) | Power ground return | High-current return path for both NMOS FETs; must be tied to large copper area for thermal and EMI control. |
| 6,7 (VIN) | Main power input | Accepts 4.5–5.5V input; dual pins reduce trace resistance and improve current sharing. |
| 8 (EN) | Enable control input | Active-high logic interface with 2µA internal pull-up; supports startup delay via external capacitor. |
| 10 (VHI) | High-side gate driver supply | Bootstrapped supply for high-side NMOS gate; requires 0.1µF CVHI capacitor to LX. |
| 11,12 (LX) | Switch node output | Drives external inductor; average voltage equals regulated output; high di/dt node requiring short layout. |
| 13 (VDRV) | Low-side driver & bootstrap input | Supplies low-side gate drive and charges CVHI during low-side conduction phase. |
| 14 (FB) | Voltage feedback input | Connects to resistor divider; 125nA internal pull-up forces shutdown if floating - critical for safety. |
| 15 (VREF) | Reference bypass | Stabilizes internal 1.26V bandgap; 0.1µF capacitor sets dominant pole for noise rejection. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated synchronous NMOS FETs | Eliminates external MOSFETs and drivers; RDS(on) 45–95 mΩ enables >90% efficiency at 1A. |
| Resistorless current sensing | Enables true cycle-by-cycle current limiting without sense resistor losses or board space. |
| Internal soft start | Prevents inrush current and output overshoot during power-up; slope fixed at 0.5 V/ms. |
| Adjustable switching frequency | Supports optimization for size (high-freq) or efficiency (low-freq); free-running range 105–130 kHz. |
| Thermal and UVLO protection | Guarantees safe operation across -40°C to +85°C ambient; disables output below 3.5V VDD. |
Applications
| DSP Core Power Supply | CPU I/O Rail |
|---|---|
Use Scenario: Powers 1.2V–1.8V core of TI C6000 or Analog Devices SHARC DSPs in portable test equipment. IC Role / Device Role / Timing Role: Primary synchronous buck regulator delivering tightly regulated, low-noise core voltage with fast load-step response. Use Value: Cycle-by-cycle current limiting and ±0.5% regulation maintain DSP stability during burst-mode processing. | Use Scenario: Supplies 3.3V I/O banks for ARM-based microcontrollers in industrial HMI panels. IC Role / Device Role / Timing Role: Fixed-frequency buck converter with external sync capability for deterministic timing in multi-rail systems. Use Value: Adjustable 1.0–3.8V output and 95% peak efficiency reduce heat buildup in sealed enclosures. |
| GTL+ Bus Power | Portable DC/DC Module |
Use Scenario: Generates 1.5V GTL+ termination voltage for high-speed memory buses in telecom line cards. IC Role / Device Role / Timing Role: Precision-adjustable buck regulator with low output drift (<±1% over temperature) for signal integrity. Use Value: ±50 ppm/°C reference tempco and <0.5% load regulation ensure stable bus voltage across thermal cycles. | Use Scenario: Embedded in compact 12mm × 12mm DC/DC module for handheld medical sensors. IC Role / Device Role / Timing Role: Monolithic 1A step-down solution minimizing external components (only inductor, caps, resistors). Use Value: 16-pin QSOP footprint and <0.4 in² total layout area enable ultra-compact, cost-effective modules. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar synchronous buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| EL7531 | Lower 0.6A output current; same 16-pin QSOP package and pinout; no VHI pin (asynchronous design). | Suitable only for sub-600mA loads; lacks bootstrapped high-side drive and synchronous efficiency. | Select when lower current and cost outweigh efficiency and thermal performance needs. |
| EL7536 | 1A output with integrated inductor; different 16-pin QFN package; no external COSC or sync capability. | Targeted at space-constrained designs where board area > efficiency; not pin-compatible. | Choose for rapid prototyping or ultra-low-profile layouts where integrated magnetics are acceptable. |
Compared with EL7551CUZ, EL7531 offers reduced current and asynchronous operation, while EL7536 trades external component flexibility for integrated magnetics and non-compatible packaging - neither provides identical functionality or drop-in replacement capability.
Availability
EL7551CUZ is available at Aetrix Electronics and suitable for DSP core supplies, CPU I/O rails, GTL+ bus power, and portable DC/DC modules requiring stable component supply, RoHS compliance, and long-term industrial availability.
Supply support for EL7551CUZ 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
Intersil Corporation (now part of Renesas Electronics) is a U.S.-based analog and power management IC designer known for high-performance DC/DC regulators, precision references, and interface solutions.
The EL7551CUZ belongs to Intersil's monolithic synchronous buck regulator product line, engineered for high-efficiency, low-noise core and I/O power in portable and embedded computing systems.
FAQ
What is the maximum output current rating of the EL7551CUZ?
The EL7551CUZ delivers 1A continuous output current under specified conditions (TA = 25°C, VIN = 5V). Peak current limit is 2A with cycle-by-cycle protection. Derating applies above +85°C ambient per thermal design guidelines in the FN7291 datasheet. The EL7551CUZ maintains regulation across its full 1.0V–3.8V output range at this current level when properly heatsinked.
Does the EL7551CUZ support external clock synchronization?
Yes, the EL7551CUZ supports external oscillator synchronization via the COSC pin. Its internal relaxation oscillator can be driven by an external source, provided the free-running frequency is at least 20% lower than the sync signal to accommodate tolerance and temperature variation. The EL7551CUZ datasheet (FN7291) shows typical sync circuitry using a BAT54S diode and 100pF capacitor.
What is the purpose of the VHI pin on the EL7551CUZ?
The VHI pin on the EL7551CUZ supplies the bootstrapped gate drive voltage for the internal high-side NMOS FET. During low-side conduction, an external 0.1µF capacitor (CVHI) charges from VDRV to ~5V; when the high-side switches on, the capacitor lifts VHI to ~10V (VDRV + VIN), enabling full enhancement of the high-side FET. This eliminates need for external high-side drivers.
How does the EL7551CUZ handle thermal overload?
The EL7551CUZ incorporates internal thermal shutdown with a 135°C junction trip point and 20°C hysteresis (115°C restart threshold). When die temperature exceeds 135°C, the device disables both FETs and holds output in shutdown until temperature falls below 115°C. This protection is independent of EN and remains active across the full -40°C to +85°C operating range.
Is the EL7551CUZ pin-compatible with other members of the EL75xx family?
No, the EL7551CUZ is not pin-compatible with EL7531 or EL7536. While all three use 16-pin packages, EL7531 omits the VHI pin and uses asynchronous rectification, and EL7536 replaces LX/VHI/VDRV with integrated inductor connections and different pin functions. The EL7551CUZ's unique 16-pin QSOP layout - including dual VIN, dual LX, and dedicated VHI - is specific to its synchronous bootstrap architecture.
EL7551CUZ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Renesas
- Series:
- -
- Package/Case:
- 16-SSOP (0.154", 3.90mm Width)
- Packaging:
- Tube
- Product Status:
- Obsolete
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 4.5V
- Voltage - Input (Max):
- 5.5V
- Voltage - Output (Min/Fixed):
- 1V
- Voltage - Output (Max):
- 3.8V
- Current - Output:
- 1A
- Frequency - Switching:
- 200kHz ~ 1MHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-QSOP
EL7551CUZ FAQ
1.How can I place an order for EL7551CUZ through Aetrix?
Please submit a Request for Quotation (RFQ) for EL7551CUZ 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 EL7551CUZ reliable?
The price and inventory of EL7551CUZ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for EL7551CUZ is usually 5 days.
3.What payment methods are accepted for EL7551CUZ?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for EL7551CUZ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for EL7551CUZ?
EL7551CUZ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your EL7551CUZ 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 EL7551CUZ?
For technical support, including EL7551CUZ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your EL7551CUZ requirements.
6.How does Aetrix verify that EL7551CUZ is sourced from the original manufacturer or authorized distributors?
All EL7551CUZ 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 EL7551CUZ meets industry standards.
7.What is the process for return or replacement of EL7551CUZ?
All EL7551CUZ units undergo pre-shipment inspection (PSI). If there is an issue with EL7551CUZ, 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 EL7551CUZ part is unused and in its original packaging.
Return procedure for EL7551CUZ:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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