Programmable ANalog Device Array (PANDA): A Methodology for Transistor-Level Analog Emulation

The design and development of analog/mixed-signal (AMS) integrated circuits (ICs) is becoming increasingly expensive, complex, and lengthy. Rapid prototyping and emulation of analog ICs will be significant in the design and testing of complex analog systems. A new approach, Programmable ANalog Device Array (PANDA) that maps any AMS design problem to a transistor-level programmable hardware, is proposed. This approach enables fast system level validation and a reduction in post-silicon bugs, minimizing design risk and cost. The unique features of the approach include: 1) transistor-level programmability that emulates each transistor behavior in an analog design, achieving very fine granularity of reconfiguration; 2) programmable switches that are treated as a design component during analog transistor emulating, and optimized with the reconfiguration matrix; and 3) compensation of ac performance degradation through boosting the bias current. Based on these principles, a digitally controlled PANDA platform is designed at 45 nm node that can map AMS modules across 22-90 nm technology nodes. A systematic emulation approach to map any analog transistor to 45 nm PANDA cell is proposed, which achieves transistor level matching accuracy of less than 5% for
I
_D
and less than 10% for
R
_out
and
G
_m
. Circuit level analog metrics of a voltage-controlled oscillator (VCO) emulated by PANDA, match to those of the original designs in 22 and 90 nm nodes with less than a 5% error. Several other 90 and 22 nm analog blocks are successfully emulated by the 45 nm PANDA platform, including a folded-cascode operational amplifier and a sample-and-hold module (S/H).