A Trim-Free PVT Invariant Current Reference with 0.48% Process Inaccuracy Using VTH Tracking Approach

The prevalence of MOSFETs in diverse electronic applications highlights their significance. However, the sensitivity of MOSFET threshold voltage to process variation poses a substantial challenge in achieving consistent device performance. This paper proposes a novel approach to overcome this challenge by employing a threshold voltage
$(V_{TH})$
tracking circuit that tracks the variation in
$V_{TH}$
. Our primary objective is to develop a current reference that remains invariant across process, voltage, and temperature (PVT) variations, eliminating the need for an external trimming circuit. This is achieved by the meticulous integration of V
TH
tracking circuit, CTAT generator, PTAT generator, and a current adder. By employing this design, a process variation
$(\frac{\sigma}{\mu})$
of 0.48%, a temperature coefficient (TC) of
${210}{ppm}/^{\circ} {C}$
‘ for a temperature range of
$-{40}/^{\circ} {C}$
to
${120}^{\circ} {C}$
, and a line sensitivity of 1.6% is achieved over a voltage range of 1.6V - 3V. The proposed circuit occupies an area of
${0.013}{mm}^{{2}}$
: while consuming power of 56μW at a typical corner of
${27}^{\circ}{C}$
and a supply of 1.8V. The given circuit is implemented in a 180nm CMOS process node with a generated reference current of 61nA.