Microchip Technology AT83C24B-PRRUL

Overview

AT83C24B-PRRUL from Microchip Technology is a smart card reader interface IC with integrated DC/DC converter, ISO 7816-compliant card power management, and TWI host control. It delivers programmable CVCC outputs (5V ±5%, 3V ±0.2V, or 1.8V ±0.14V), supports 4–48 MHz clock input, achieves up to 98% step-up converter efficiency, and operates across –40°C to +85°C for EFT/POS terminals and set-top boxes.

For engineers reviewing the AT83C24B-PRRUL datasheet, AT83C24B-PRRUL pinout, AT83C24B-PRRUL application, or AT83C24B-PRRUL equivalent, key selection considerations include its dual-mode TWI address configuration (up to 8 devices), hardware/software activation flexibility, card presence detection via CPRES, and Class A/B voltage compliance per ISO 7816-3.

Technical Context

The AT83C24B-PRRUL integrates a high-efficiency step-up DC/DC converter (80–98% efficiency) with programmable output voltage (CVCC) for smart card power delivery, and a dedicated TWI controller supporting up to 400 kbit/s with configurable slave addressing via A2/CK, A1/RST, and A0/3V pins. Its clock controller accepts 4–48 MHz input and generates CCLK with stop-high/stop-low modes for card power-down.

It implements full ISO 7816-3 timing compliance including automatic reset transition (ART) with 16-bit timer-based CRST control, ATR delay capture, and synchronized deactivation sequencing. The device features dual power monitoring (VCC or internal 3V regulator), open-drain PRES/INT with IT_SEL-selectable card presence/interrupt mode, and 8 kV+ ESD protection on CVCC-domain pins (CIO, CC4, CC8, CPRES, CCLK, CRST).

Key Specifications

Pinout & Package

AT83C24B-PRRUL is available in SO28 and QFN28 packages. Both packages share identical pin functions and electrical characteristics; pin numbering differs per mechanical layout but signal mapping is fully compatible.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SLB9670 and SC16IS752, AT83C24B-PRRUL provides complete, standards-compliant smart card physical layer integration - including programmable CVCC, ART-controlled reset, and 8 kV+ ESD protection - reducing total system BOM count by ≥7 components and eliminating timing-critical firmware development.

Availability

AT83C24B-PRRUL is available at Aetrix Electronics and suitable for EFT/POS terminals, set-top boxes, and government ID readers requiring stable component supply, long-term lifecycle assurance, and industrial temperature operation.

Supply support for AT83C24B-PRRUL 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 devices, and security ICs, with broad expertise in secure transaction and embedded connectivity solutions.

The AT83C24B-PRRUL belongs to Microchip's Smart Card Interface family, designed specifically to simplify ISO 7816-compliant reader development by integrating power management, timing control, and host interface into a single IC.

FAQ

What is the minimum clock frequency required for AT83C24B-PRRUL step-up converter operation?

The AT83C24B-PRRUL requires a minimum 7 MHz input clock for proper step-up converter operation, as specified in the electrical characteristics section of the official datasheet (document 4234G–SCR–01/07). This ensures stable DC/DC regulation when generating 5V CVCC from lower VCC rails. Frequencies below 7 MHz may cause output voltage droop or instability in Class A operation.

Does AT83C24B-PRRUL support both 3V and 5V smart cards simultaneously?

No - AT83C24B-PRRUL supports only one CVCC voltage at a time, selected during activation via A0/3V pin (hardware) or VCARD[1:0] bits (software). To switch between 3V and 5V cards, the device must execute a full deactivation sequence before reconfiguring CVCC. This ensures strict compliance with ISO 7816-3 voltage transition timing requirements.

How does AT83C24B-PRRUL handle card presence detection?

AT83C24B-PRRUL uses the dedicated CPRES pin with programmable polarity (CARDDET bit) and digital filtering (CDS[2:0] bits) to detect card insertion/extraction. An internal pull-up can be enabled or disabled via the PULLUP bit, allowing flexible connection to either VCC or VSS. Detection status is reported via INSERT bit in CONFIG0 and optionally drives PRES/INT when IT_SEL = 0.

Can AT83C24B-PRRUL operate without the step-up converter?

Yes - AT83C24B-PRRUL can operate in regulator mode by setting STEPREG = 1, bypassing the DC/DC converter. In this mode, CVCC is derived directly from VCC (e.g., 5V CVCC from 5.25V VCC), supporting Class A cards without boosting. LI pin must be tied to VCC, and CVCC decoupling remains mandatory per datasheet Table 20.

What is the purpose of the ART (Automatic Reset Transition) feature in AT83C24B-PRRUL?

The ART feature in AT83C24B-PRRUL uses a 16-bit counter synchronized to CCLK to precisely control CRST timing during cold reset, ensuring compliance with ISO 7816-3 parameters: ta ≥ 200 cycles, tb ≥ 400 cycles, and tc ≤ 40000 cycles. It captures ATR arrival time in CAPTURE[1:0] registers and automatically terminates reset if ATR arrives early - critical for interoperability with diverse card vendors.