Microchip Technology AT83C24NDS-TISUL

Overview

AT83C24NDS-TISUL from Microchip Technology is a smart card reader interface IC with integrated DC/DC converter, designed for NDS VideoGuard conditional access systems in set-top boxes. It delivers programmable 1.8V/3V/5V card supply (±0.14V at 40 mA), supports ISO 7816/EMV2000/GSM standards, provides 8 kV+ ESD protection on card I/O pins, and operates with 18–48 MHz clock input.

For engineers reviewing the AT83C24NDS-TISUL datasheet, AT83C24NDS-TISUL pinout, AT83C24NDS-TISUL application, or AT83C24NDS-TISUL equivalent, key selection considerations include NDS-specific certification, mandatory 3.3 µF CVCC decoupling, 18 MHz minimum clock requirement, IT_SEL=1 interrupt behavior, and dual SO28/QFN28 package support.

Technical Context

The AT83C24NDS-TISUL implements a TWI-controlled smart card interface with hardware- and software-activation modes, automatic reset transition (ART) timing control, and transparent mode for direct ISO 7816 signal pass-through. Its clock controller selects CCLK source from CLK, DCCLK, A2/CK, or CARDCK, while CRST is driven either by A1/RST (transparent) or by internal logic with ART-based timing.

Power management includes five operational modes: step-up (80–98% efficiency), regulator, DC/DC-off, and two shutdown states (90 µA and 30 µA). The device integrates POR/PFD supervision, programmable voltage supervisor thresholds, and card presence detection with configurable polarity and filtering via CPRES and CONFIG1 register bits.

Key Specifications

Pinout & Package

AT83C24NDS-TISUL is available in SO28 and QFN28 packages. Both packages share identical pin functions and electrical characteristics; pin numbering differs per mechanical layout but functional mapping is consistent across variants.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar smart card interface applications.

Compared with AT83C24B-SU, AT83C24NDS-TISUL enforces stricter NDS requirements (18 MHz clock, 3.3 µF CVCC, IT_SEL=1), while SLB9670TT10 serves a fundamentally different security role without smart card power management - making AT83C24NDS-TISUL irreplaceable in certified VideoGuard deployments.

Availability

AT83C24NDS-TISUL is available at Aetrix Electronics and suitable for pay-TV set-top boxes, EMV payment terminals, secure identity readers, and GSM SIM modules requiring stable component supply and NDS VideoGuard certification.

Supply support for AT83C24NDS-TISUL 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

Microchip Technology is a global semiconductor company specializing in microcontrollers, analog components, and security solutions for embedded systems.

The AT83C24 product line was designed specifically for smart card reader/writer applications in EFT/POS, set-top boxes, and secure identification systems - with AT83C24NDS-TISUL optimized for NDS VideoGuard conditional access compliance.

FAQ

What distinguishes AT83C24NDS-TISUL from the standard AT83C24B?

The AT83C24NDS-TISUL is a NDS-certified variant of the AT83C24B with three mandatory differences: 18 MHz minimum clock input (vs. 7 MHz), 3.3 µF CVCC capacitor requirement (vs. up to 10 µF), and fixed IT_SEL=1 interrupt behavior for card presence indication. These ensure compatibility with NDS VideoGuard conditional access software in set-top boxes. AT83C24NDS-TISUL shares full register compatibility and pinout with AT83C24B but must be used where NDS certification is required.

Does AT83C24NDS-TISUL support 1.8V smart cards?

Yes, AT83C24NDS-TISUL supports 1.8V smart cards with ±0.14V regulation at up to 40 mA. Voltage selection is programmable via VCARD[1:0] bits in CONFIG0 register or hardware-selected using A0/3V pin state. The 1.8V mode is fully compliant with ISO 7816-3 and EMV2000 standards, and the device provides dedicated short-circuit current limiting and 8 kV+ ESD protection on CIO/CC4/CC8 pins for robust low-voltage operation.

What is the purpose of the IT_SEL bit in AT83C24NDS-TISUL?

The IT_SEL bit (in CONFIG4 register) configures PRES/INT output behavior and is fixed to 1 in AT83C24NDS-TISUL for NDS compliance. When IT_SEL=1, PRES/INT is high to indicate card presence and absence of faults (over-current, VCARDERR, ATR timeout); it goes low only upon error detection. This differs from IT_SEL=0 mode (used in AT83C24B) where PRES/INT asserts low on multiple events including card insertion. AT83C24NDS-TISUL requires IT_SEL=1 to meet NDS VideoGuard software interface expectations.

Can AT83C24NDS-TISUL operate from a single 3.3V supply?

Yes, AT83C24NDS-TISUL operates from a single 3–5.5 V supply on VCC. Its integrated high-efficiency step-up DC/DC converter generates regulated CVCC outputs (1.8V/3V/5V) for the smart card, eliminating need for external regulators. With VCC = 3.3V, the device enters step-up mode (MODE 1) delivering up to 65 mA at 5V to Class A cards. Efficiency reaches 80–98%, and LI pin connects to VCC via 4.7 µH inductor to enable charge-pump operation.

Is AT83C24NDS-TISUL pin-compatible with AT83C24B?

Yes, AT83C24NDS-TISUL is fully pin-compatible with AT83C24B in both SO28 and QFN28 packages. All 28 pins have identical functions, electrical characteristics, and mechanical footprints. However, due to NDS-specific requirements (18 MHz clock, 3.3 µF CVCC, IT_SEL=1), direct substitution in non-NDS designs may require validation of timing margins and capacitor selection - though no PCB layout changes are needed.