1.1 Architecture block diagram

A block diagram  of the Rifle architecture is shown in Figure 1 . The Rifle instrument is connected to a PC by means of a PCI controller housed inside the PC case. This controller maps the DUT (Device Under Test) array into the PCI addressing space providing a very fast end direct access to the memory cells or the array. Since the data collected is processed and stored by the PC the Rifle architecture also benefits of the great capabilities offered by the modern desktop computers and of the possibility of easily upgrade the system.

The PC can be easily expanded with standard interfaces, like GPIB, to control supplementary instrumentations, like probers, handlers, ovens. Their control can be integrated into the measurement flow to perform very complex automatic tasks.

Figure 1 . RIFLE architecture block diagram
(click to enlarge)

1.2 The main controller

By means of the PCI controller the PC communicates with the Rifle main controller that drives all the hardware circuits of the system and generates the access cycles to the DUT. The main controller provides enhanced synchronization capabilities between analog and digital circuits in order to perform static or transitory measurements during any device operation.

The main digital resources provided by the hardware are in excess of 100 I/Os. The linear addressing space is 512Mbytes (2 Gbytes paged). The bus width can be programmed as 8, 16 or 32 bits. Different configurations of multiplexed/demultiplexed address/data busses are programmable as well as single or burst  transfers.

The digital resources can be controlled by software or can be automatically driven and evaluated by hardware by a programmable state machine, called GPI (General Programmable Interface), in order to generate any kind of access cycle that matches the DUT timing requirements.

1.3 Level translators

The DUT digital power supply and the digital I/O levels can be programmed from 1.2V to 4V to match the voltage level of a wide range of devices.

1.4 Arbitrary waveform generators

RIFLE has internal expansion slots where up to 16 independent AWGs (Arbitrary Waveform Generators) can be installed. This allows to evaluate the impact of any modification in the waveform shape and duration applied during writing operations on long term reliability. The standard AWGs installed in the system have a 80Msps update rate and 12 bit of resolution. Faster AWGs with 100Msps update rate and 12 or 14 bit of resolution are also available.

Custom expansions boards can also be installed in place of the AWGs to meet specific customer requirements.

1.5 The PMU

A circuit called PMU (Programmable Measurement Unit) is inserted in the path of the data bus to the output connectors. The PMU unit can perform accurate and fast current measurements on single cells, like I-V characteristics,  as well as on large memory regions, like current maps or distributions.

This circuit can force a voltage on two adjacent bits of the bus and it can simultaneously measure the current provided to the output pins. The current provided to the two pins is evaluated simultaneously by two ADC (Analog to Digital Converter) in parallel. The measurement resolution in 12 bits and the conversion time is 1.5ms/channel. Two full scales are available: ±50mA, ±500mA.

1.6 The current generator

Rifle has a current generator circuit to generate a reference current (IREF) sometimes necessary for the read operations of the DUT. The unit has two full scales of  ±66mA and ±666mA and a resolution of 12 bits.

1.7 The PW0

A unit called PW0 unit is placed in series to all the analog and digital outputs. This unit can be used statically to perform a continuity check on every pin of the DUT or dynamically to evaluate the transitory power consumption during read/write operations. 

The PW0 unit is made of a programmable switch matrix that can connect any output pin to an AWG through a current measurement circuit. This way it is possible to apply an arbitrary signal to any pin of the device while measuring the evolution of the current provided to that pin. The current is sampled by an high speed ADC and the samples are stored in FIFO inside the main controller. The ADC has a 40Msps sampling frequency and 10 bits of resolution. Two full scales are available: ±500mA, ±5mA, ±50mA.