A read reference generator with negative temperature coefficient for 3D NAND flash memory

3D NAND flash reliability is vulnerable to temperature variation due to the threshold voltages (V_TH) shift, which will further deteriorate the read margin. To solve this issue, a read reference generator with negative temperature coefficient was proposed to compensate the V_TH shift under the changes of temperature. The proposed generator outputs different level voltages with the same negative temperature coefficient by adjusting the CTAT (complementary to absolute temperature) current and ZTAT (zero to absolute temperature) current, respectively. And the regulator was used to enhance the range of output voltage. The results showed the proposed method could provide a configurable range of read voltage of 1.5~4.5 V.