Nexperia USA Inc. NXT4556UPAZ

Overview

NXT4556UPAZ from Nexperia is a dedicated SIM card interface level translator IC that bridges 1.08–1.98 V host microcontrollers with 1.62–3.3 V SIM/eSIM cards via three independent bidirectional/unidirectional channels (IO_HOST/IO_SIM, CLK_HOST/CLK_SIM, RST_HOST/RST_SIM). It supports Class-B/C SIM cards, delivers <1 μA shutdown current, and executes ISO-7816-3-compliant shutdown sequencing in ~4 μs. Used in mobile phones and wireless modems for secure, low-power SIM interfacing.

For engineers reviewing the NXT4556UPAZ datasheet, NXT4556UPAZ pinout, NXT4556UPAZ application, or NXT4556UPAZ equivalent, key selection criteria include its integrated EMI filters, AC-coupled UVLO (Vdis(UVLO_AC) ≈ 0.86×VCC_SIM), 9-bump WLCSP9 package (1.06 × 1.06 × 0.43 mm), and robust ±8 kV contact / ±15 kV air IEC61000-4-2 ESD protection on all SIM-side pins.

Technical Context

The NXT4556UPAZ implements a dual-voltage domain architecture with separate VCC_HOST (1.08–1.98 V) and VCC_SIM (1.62–3.3 V) supplies. Its I/O channel uses active pull-up (PMOST + one-shot pulse) and passive pull-down (Rpd) to enable automatic direction detection without control signals - critical for open-drain SIM communication.

Shutdown is triggered by VCC_SIM falling below Vdis(UVLO_AC), initiating a deterministic sequence: RST_SIM → CLK_SIM → IO_SIM pulled LOW via internal 400 Ω pull-downs. All outputs are disabled, and SIM-side pull-ups are deactivated, ensuring compliance with ISO-7816-3 hot-swap safety requirements.

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. Pin 1 (A1) located at lower-left corner beneath marking code 'z6'.

Key Features

Applications

Equivalent & Alternatives

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

Compared with NX30P2556UK and MAX14712, the NXT4556UPAZ uniquely combines dual-rail operation, deterministic ISO-7816-3 shutdown, integrated EMI filtering, and full IEC61000-4-2 Level 4 protection - making it the only drop-in solution for space-constrained, safety-critical mobile and payment SIM interfaces.

Availability

NXT4556UPAZ is available at Aetrix Electronics and suitable for mobile handsets, wireless modems, and industrial telematics terminals requiring stable component supply, long-term lifecycle support, and RoHS/Dark Green compliance.

Supply support for NXT4556UPAZ 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, reliable, and sustainable components for automotive, industrial, and consumer markets.

The NXT4556UPAZ belongs to Nexperia's SIM interface translator product line, engineered specifically to simplify dual-voltage SIM/eSIM integration while meeting stringent ESD, EMI, and ISO-7816-3 safety requirements in portable and connected devices.

FAQ

Does NXT4556UPAZ support both push-pull and open-drain drivers on the IO_HOST pin?

Yes. The IO_HOST pin accepts both push-pull and open-drain drive configurations. Its input stage is designed to detect logic levels across the full VCC_HOST range (1.08–1.98 V), and the internal control logic automatically adapts to either driver type without external configuration or direction control signals.

What is the exact timing behavior of the ISO-7816-3 shutdown sequence?

The shutdown sequence initiates within nanoseconds of VCC_SIM crossing Vdis(UVLO_AC) (~0.86×VCC_SIM). RST_SIM is pulled LOW first, followed by CLK_SIM and IO_SIM sequentially, each delayed by ≤2 µs. Total sequence duration is typically 4 µs, with all SIM-side pins driven LOW via internal 400 Ω pull-down resistors - fully compliant with ISO-7816-3 Clause 7.2.

Can NXT4556UPAZ operate with VCC_HOST = 1.08 V and VCC_SIM = 3.3 V simultaneously?

Yes. The device is fully specified for simultaneous operation across the entire recommended ranges: VCC_HOST (1.08–1.98 V) and VCC_SIM (1.62–3.3 V), including the extreme combination of 1.08 V/3.3 V. Electrical characteristics such as VIH/VIL thresholds, propagation delay, and output drive strength are guaranteed across this full operating window.

Is external decoupling required on VCC_HOST and VCC_SIM pins?

Yes. A 0.1 µF ceramic capacitor must be placed as close as possible to each supply pin (VCC_HOST and VCC_SIM) to ensure stable operation, minimize switching noise, and maintain ESD performance. This requirement is explicitly stated in Table 3 (Pin Description) and Fig. 10 (Application Circuit) of the official datasheet.