Renesas EL7536IY

Overview

EL7536IY from Intersil is a synchronous, integrated-FET 1A step-down DC/DC regulator in a 10-lead MSOP package, operating from 2.5V to 5.5V input and delivering adjustable output from 0.8V to VIN with internal compensation. It features 1.4MHz PWM switching, <1µA shutdown current, 100ms open-drain POR output, and over-temperature/short-circuit protection-designed for space-constrained Li-Ion–powered portable electronics.

For engineers reviewing the EL7536IY datasheet, EL7536IY pinout, EL7536IY application, or EL7536IY equivalent, key selection considerations include its internally compensated voltage-mode control architecture, dual ground separation (SGND/PGND), fixed 1.4MHz switching frequency, 70mΩ PMOS/45mΩ NMOS R_DS(ON), and thermal shutdown at 145°C with 15°C hysteresis.

Technical Context

The EL7536IY implements a voltage-mode PWM controller with fixed internal compensation, eliminating external loop components. Its synchronous rectification uses complementary PMOS (70mΩ) and NMOS (45mΩ) switches, enabling 100% duty-cycle operation near VIN and eliminating boot capacitor requirements.

It integrates a bandgap reference, soft-start (650µs), POR generator with 100ms delay, and independent EN/RSI logic inputs. The dual-ground architecture (SGND for control, PGND for power stage) supports clean signal integrity and thermal management via fused-lead MSOP10 packaging rated for –40°C to +85°C ambient.

Key Specifications

Pinout & Package

EL7536IY is housed in a 10-lead MSOP package (MDP0043), 3.0mm × 4.9mm × 1.1mm max height, with fused-lead construction for improved thermal resistance (θ_JA = 100°C/W on 4-layer board). Dual ground pins (SGND and PGND) require separate copper pours joined at a single point near the IC.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar step-down regulator applications.

Compared with EL7536IY, ISL97536 offers direct replacement capability with improved specs and lifecycle support, while TPS62231DRVR demands layout and firmware changes due to missing POR, different pin functions, and absence of dual-ground architecture.

Availability

EL7536IY is available at Aetrix Electronics and suitable for bar code readers, cellular phones, portable test equipment, Li-Ion–powered devices, and small form factor (SFP) modules requiring stable component supply across industrial temperature ranges.

Supply support for EL7536IY 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, designs high-performance analog and power management ICs with emphasis on efficiency, integration, and reliability for portable and industrial systems.

The EL7536IY belongs to Intersil's monolithic synchronous buck regulator product line, engineered specifically for space- and power-constrained battery-operated applications demanding minimal external components and robust protection features.

FAQ

What is the recommended inductor value for EL7536IY in a standard 1.8V/1A application?

The EL7536IY datasheet specifies a nominal inductor value of 1.8µH for 1.8V/1A operation with 3.3V input. Inductor values between 1.5µH and 2.2µH are acceptable due to fixed internal compensation. The selected inductor must handle ≥1.5A peak current (including current limit surges) and ≥1A RMS current. For optimal efficiency and ripple, use shielded power inductors with low DCR and saturation current rating ≥2A.

Does EL7536IY support 100% duty cycle operation, and what is its practical impact?

Yes, EL7536IY supports 100% duty cycle operation using its integrated PMOS high-side switch, enabling output voltages approaching VIN minus IR drops. This is critical for Li-Ion systems where VIN may dip near VO. However, at near-100% duty, random off-time causes increased output ripple; adding larger output capacitance (e.g., 22µF) mitigates this effect. The maximum achievable VO is VO = VIN − IO × (RL + RDSON1), where RDSON1 ≈ 70mΩ at 25°C.

How should the POR and RSI pins be configured if the Power-On Reset function is not needed in my design?

If POR functionality is unused, connect RSI directly to SGND (not left floating), and leave the POR pin unconnected or pulled up externally only if needed for system-level Power-Good indication. Do not install pull-up resistor R4 unless POR is actively used - doing so unnecessarily loads the open-drain output and consumes extra current during normal operation. The EL7536IY operates correctly without POR activation.

What is the difference between SGND and PGND on EL7536IY, and why must they be separated?

SGND is the reference ground for control circuitry (error amplifier, PWM comparator, bandgap), while PGND carries high di/dt return current from the LX switch node and power FETs. Separating them prevents noise coupling from power switching into sensitive analog circuits. They must join at a single point near the EL7536IY package - typically at the PGND pad - to avoid ground loops. Failure to isolate SGND/PGND degrades regulation accuracy and can cause instability or false POR triggering.

Is EL7536IY RoHS compliant, and what does "Pb-free plus anneal" mean for this part?

Yes, EL7536IY is RoHS compliant. The "Pb-free plus anneal" designation indicates Intersil's proprietary process: 100% matte tin termination finish applied after annealing to prevent tin whisker formation, with Pb-free molding compound and die attach materials. These parts meet IPC/JEDEC J-STD-020 reflow profiles for both SnPb and lead-free soldering and are MSL Level 1 rated. The EL7536IY variant is fully compatible with modern assembly processes without requiring special handling.