Title :
A low-voltage low-power analog memory cell with built-in 4-quadrant multiplication
Author :
De Lima, Jader A. ; Cordeiro, Adriano S.
Author_Institution :
Lab. of VLSI Design & Instrum., Univ. Estadual Paulista, Sao Paulo, Brazil
fDate :
4/1/2003 12:00:00 AM
Abstract :
An accurate switched-current (SI) memory cell and suitable for low-voltage low-power (LVLP) applications is proposed. Information is memorized as the gate-voltage of the input transistor in a tunable gain-boosting triode-transconductor. Additionally, four-quadrant multiplication between the input voltage to the transconductor regulation-amplifier (X-operand) and the stored voltage (Y-operand) is provided. A simplified 2×2-memory array was prototyped according to a standard 0.8 μm n-well CMOS process and 1.8-V supply. Measured current-reproduction error is less than 0.26% for 0.25 μA ≤ ISAMPLE ≤ 0.75 μA. Standby consumption is 6.75 μW per cell at ISAMPLE=0.75 μA. At room temperature, leakage-rate is 1.56 nA/ms. Four-quadrant multiplier (4QM) full-scale operands are 2xmax=320 mVpp and 2ymax=448 mVpp, yielding a maximum output swing of 0.9 μApp. 4QM worst-case nonlinearity is 7.9%.
Keywords :
CMOS analogue integrated circuits; analogue multipliers; analogue storage; low-power electronics; switched current circuits; 0.75 muA; 0.8 micron; 1.8 V; 6.75 muW; LV analog memory cell; SI memory cell; built-in 4-quadrant multiplication; four-quadrant multiplication; gain-boosting triode-transconductor; input transistor gate-voltage; low-power applications; low-voltage applications; memory array; n-well CMOS process; switched-current memory cell; transconductor regulation-amplifier; tunable triode-transconductor; Analog memory; CMOS process; Capacitance; Current measurement; Neural networks; Prototypes; Transconductors; Tunable circuits and devices; Very large scale integration; Voltage;
Journal_Title :
Circuits and Systems II: Analog and Digital Signal Processing, IEEE Transactions on
DOI :
10.1109/TCSII.2003.810575
