Title :
An enhanced slew rate source follower
Author :
Kenney, John G. ; Rangan, Giri ; Ramamurthy, Karthik ; Temes, Gabor
Author_Institution :
Dept. of Electr. & Comput. Eng., Oregon State Univ., Corvallis, OR, USA
fDate :
2/1/1995 12:00:00 AM
Abstract :
A unity-gain buffer capable of high slew rates in both the positive and negative directions is presented. By sensing the drain current of the common-drain device in an NMOS source follower, the extent of slewing is detected, and the tail current of the source follower is dynamically adjusted. A buffer incorporating this strategy was implemented in a 2 μm p-well process. This buffer has over 4 times the negative-going slew rate and twice the bandwidth of a source follower, while requiring only 13% more static power. Moreover, the output voltage swing range is as large as that of a source follower. With a 20 pF output load, the measured 3-dB bandwidth was 9 MHz. The signal-to-total-harmonic-distortion ratio with 2 Vp-p sinewave input at a frequency of 2 MHz was better than 50 dB
Keywords :
CMOS analogue integrated circuits; buffer circuits; circuit feedback; circuit stability; 2 MHz; 2 micron; 9 MHz; CMOS; NMOS source follower; common-drain device; drain current sensing; high slew rates; p-well process; slew rate source follower; tail current dynamic adjustment; unity-gain buffer; Bandwidth; Energy consumption; Frequency; Helium; Impedance; MOS devices; MOSFETs; Semiconductor diodes; Tail; Threshold voltage;
Journal_Title :
Solid-State Circuits, IEEE Journal of
