WM710xx – Secure F-RAM with Gen-2 RFID
FUNCTIONAL DESCRIPTION
The WM710xx is a non-volatile memory device with an industry standard UHF RFID interface that enables
processing data in and out of memory as a generic passive RFID transponder. Unlike other transponder ICs,
the WM710xx transponder IC contains high density symmetric read/write F-RAM memory that enables unique
applications of an RFID solution.
When combined with an appropriate antenna design, WM710xx will power up with energy harvested directly
from the RF field. Following an internally generated reset state, the IC configures itself according to pre-
programmed configuration settings that were stored in F-RAM non-volatile memory at wafer probe, packaged
parts test, or end unit transponder personalization at end-user depot. Configuration settings are read out of
memory and applied prior to enabling data transmission in or out of memory.
As specified in the Gen2 standard, the chip receives and processes commands transmitted by the RFID
interrogator (reader). All required and most optional commands are supported. In addition to these,
WM710xx supports a number of custom commands that take advantage of F-RAM’s unique ultra low power
and symmetrical characteristics.
Referring to Figure 2, the transponder IC’s consist of an RFID interface, control and authentication logic, F-
RAM memory, and power management unit. The external antenna is connected directly to the RFID interface
where the RF signal is rectified with high efficiency Schottky diode based rectifier. The rectified voltage is
multiplied up within the Schottky array and then regulated to supply power to on-chip resources.
Also included in the RFID Interface is a modulator/demodulator that detects incoming signals and modulates
the input impedance to enable backscattering of returned signals. The control and authentication logic
processes commands to enable access in and out of F-RAM memory.
Control and
RFID
Authentication
Logic
Interface
Power
External
MCU
F-RAM Array
Management
(16Kb)
(Optional)
Figure 2. Block Diagram
Rev. 1.2
Sept. 2010
Page 3 of 17
RAMTRON [ RAMTRON INTERNATIONAL CORPORATION ]
