Nexperia USA Inc. NXT4556UPZ

Overview

NXT4556UPZ 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 (I/O, RST, CLK), supports ISO-7816-3-compliant shutdown sequencing, delivers <1 μA shutdown current, and operates across –40 °C to +85 °C in mobile and wireless modem applications.

For engineers reviewing the NXT4556UPZ datasheet, NXT4556UPZ pinout, NXT4556UPZ application, or NXT4556UPZ equivalent, key selection criteria include its WLCSP9 package with 0.35 mm pitch, integrated EMI filters on all SIM-side outputs, AC-coupled UVLO with Vdis(UVLO_AC) ≈ 0.86×VCC_SIM, and support for open-drain and push-pull I/O drive modes up to 5 Mbps data rate.

Technical Context

The NXT4556UPZ implements an auto-direction-sensing bidirectional I/O channel using dual one-shot-controlled PMOS pull-ups and NMOS drivers, eliminating external direction control signals. Its RST and CLK paths are unidirectional high-speed translators with <12 ns propagation delay at 1.8 V/3.0 V supplies.

Shutdown behavior follows ISO-7816-3: upon VCC_SIM falling below Vdis(UVLO_AC), RST_SIM is pulled low first, followed by CLK_SIM and IO_SIM within 4 μs (typical), using internal 400 Ω pull-down resistors - all without host intervention.

Key Specifications

Pinout & Package

Package: Wafer Level Chip-Scale Package (WLCSP9), SOT8027-1, 9-bump array, 1.06 mm × 1.06 mm × 0.43 mm body, 0.35 mm pitch, bottom-side bump configuration with pin 1 indicator in lower-left corner beneath marking "z6".

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX14430ETE+ and TXS0102DCUR, the NXT4556UPZ uniquely integrates SIM-specific functions - including AC-UVLO-triggered shutdown, auto-direction I/O, and EMI-filtered outputs - in a 1.06 mm × 1.06 mm WLCSP, making it the only drop-in solution for production-grade, space-constrained, ISO-compliant SIM interfaces.

Availability

NXT4556UPZ is available at Aetrix Electronics and suitable for mobile handsets, wireless modems, SIM card terminals, and industrial M2M routers requiring stable component supply, long-term lifecycle assurance, and RoHS/Dark Green compliance.

Supply support for NXT4556UPZ 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 delivering high-performance, reliable, and efficient logic, discrete, and MOSFET solutions optimized for automotive, industrial, and mobile markets.

The NXT4556UPZ belongs to Nexperia's SIM interface translator product line, engineered specifically to simplify and harden SIM/eSIM connectivity in battery-powered, space-constrained, and ESD-sensitive wireless devices.

FAQ

What is the minimum VCC_SIM voltage required to maintain normal operation?

The NXT4556UPZ remains active until VCC_SIM falls below Ven(UVLO), specified at 0.85 V (min) for VCC_HOST = 1.8 V. Operation is guaranteed across 1.62 V to 3.3 V, and the device enters shutdown only when VCC_SIM drops below Vdis(UVLO_AC) ≈ 0.86×VCC_SIM - a slope-dependent threshold designed to avoid false triggers during slow power ramps.

Does the NXT4556UPZ require external pull-up resistors on the IO_HOST or IO_SIM lines?

No. The NXT4556UPZ integrates internal pull-up resistors of 2.8–6 kΩ on IO_HOST and 3.3–7.3 kΩ on IO_SIM, eliminating the need for external components. These values are optimized for standard SIM I/O loading and ensure proper HIGH-state biasing during idle and transition periods without compromising speed or EMI performance.

How does the auto-direction sensing work on the I/O channel?

The I/O channel detects the first falling edge on either IO_HOST or IO_SIM and immediately grants output control to the opposite side via one-shot-activated PMOS pull-ups and NMOS drivers. Direction changes occur seamlessly when both nodes are HIGH, with no external control signal needed - enabling true bidirectional communication in open-drain or push-pull configurations without timing overhead.

Can the NXT4556UPZ support 25 MHz clock operation on the CLK channel?

Yes. The CLK channel supports up to 25 MHz push-pull operation with typical propagation delay of 7–12 ns (depending on supply voltage), meeting timing requirements for high-speed SIM Class-C interfaces. This capability is validated under recommended operating conditions (VCC_HOST = 1.2 V/1.8 V, VCC_SIM = 1.8 V/3.0 V) and includes integrated 44 Ω series resistance and EMI filtering to preserve signal integrity.