Nexperia USA Inc. NXT4556AURZ

Overview

NXT4556AUR from Nexperia is a dedicated SIM card interface level translator IC that provides bidirectional voltage translation between 1.08 V–1.98 V host microcontrollers and 1.62 V–3.3 V SIM/eSIM cards. It integrates three independent level-shifting channels (IO, RST, CLK), supports >5 MHz clock rates, complies with ISO/IEC 7816-3 shutdown sequencing, and delivers <1 μA shutdown current. It is deployed in mobile phones and wireless modems for secure, hot-swap–capable SIM interfacing.

For engineers reviewing the NXT4556AUR datasheet, NXT4556AUR pinout, NXT4556AUR application, or NXT4556AUR equivalent, key selection criteria include its dual-voltage domain operation (VCC_HOST/VCC_SIM), integrated ISO-7816-3–compliant shutdown logic, EMI-filtered outputs, on-chip 20 kΩ pull-ups, and WLCSP9 package compatibility with space-constrained portable designs.

Technical Context

The NXT4556AUR implements an autonomous bidirectional I/O channel using PMOS/NMOS output stages with one-shot acceleration for fast LOW-to-HIGH transitions, eliminating direction-control pins. Its RST and CLK channels are unidirectional high-speed translators optimized for SIM timing compliance.

Shutdown is triggered by AC-coupled UVLO detection (Vdis(UVLO_AC) ≈ 0.86 × VCC_SIM) initiating a precise 4 μs sequence: RST_SIM → CLK_SIM → IO_SIM pulled low via internal 400 Ω pull-downs, satisfying ISO-7816-3 requirements for safe SIM power removal during hot swap.

Key Specifications

Pinout & Package

Package: WLCSP9 (SOT8057-1), 0.92 mm × 0.92 mm × 0.42 mm body, wafer-level chip-scale package with 9 solder bumps and NSMD pad layout optimized for low-inductance grounding and ESD robustness.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar SIM interface level translation applications.

Compared with MAX14430ETA+ and TXS0102DCT, the NXT4556AUR uniquely combines triple-channel SIM-specific translation, ISO-7816-3–compliant shutdown, ±15 kV SIM-side ESD, and integrated pull-ups-enabling drop-in compliance in certified mobile and industrial SIM interfaces without component count increase or timing risk.

Availability

NXT4556AUR is available at Aetrix Electronics and suitable for mobile handsets, wireless modems, SIM card terminals, and eSIM integration platforms requiring stable component supply across automotive-grade temperature ranges (−40 °C to +85 °C).

Supply support for NXT4556AUR 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

Nexperia is a global semiconductor expert focused on essential efficiency technologies, delivering high-performance, high-reliability standard products for automotive, industrial, and mobile markets.

The NXT4556AUR belongs to Nexperia's SIM interface translator product line, engineered specifically to simplify secure, standards-compliant SIM/eSIM connectivity in space- and power-constrained portable electronics.

FAQ

What is the minimum VCC_HOST voltage required for reliable operation?

The NXT4556AUR requires VCC_HOST ≥ 1.08 V to guarantee full specification compliance-including propagation delay, output drive strength, and ESD performance. Operation below this threshold may result in undefined behavior, increased ICC, or failure to meet ISO-7816-3 timing during shutdown. The device is not characterized or guaranteed for sub-1.08 V use.

Does the NXT4556AUR support 3.3 V SIM cards?

Yes, the NXT4556AUR fully supports 3.3 V SIM cards, with VCC_SIM rated from 1.62 V to 3.3 V. All electrical characteristics-including VOH, VOL, and ESD protection-are validated across this entire range. Its 3.3 V capability enables backward compatibility with legacy SIM modules while maintaining interoperability with modern 1.8 V eSIMs.

How does the shutdown sequence protect against SIM data corruption?

The shutdown sequence protects against data corruption by asserting RST_SIM low first (within 4 μs of VCC_SIM undervoltage), forcing the SIM into reset before CLK_SIM and IO_SIM are pulled low. This prevents partial clock cycles or mid-byte data writes during power collapse-directly implementing ISO/IEC 7816-3 Annex A requirements for safe hot removal and power gating.

Can IO_HOST be driven by an open-drain host controller?

Yes, IO_HOST accepts both push-pull and open-drain inputs. When driven open-drain, the internal 20 kΩ pull-up ensures valid HIGH levels, and the one-shot circuit accelerates rising edges to meet 100 kbps open-drain timing. The control logic automatically arbitrates direction based on signal edges-no external direction control is needed.