Byung-sik Moon

A 32-bank 1 Gb self-strobing synchronous DRAM with 1 GByte/s bandwidth

This paper describes a 32-bank 1 Gb DRAM achieving 1 Gbyte/s (500 Mb/s/DQ pin) data bandwidth and the access time from RAS of 31 ns at V/sub cc/=2.0 V and 25/spl deg/C. The chip employs (1) a merged multibank architecture to minimize die area; (2) an extended small swing read operation and a single I/O line driving write scheme to reduce power consumption; (3) a self-strobing I/O schemes to achieve high bandwidth with low power dissipation; and (4) a block redundancy scheme with increased flexibility. The nonstitched chip with an area of 652 mm/sup 2/ has been fabricated using 0.16 /spl mu/m four-poly, four-metal CMOS process technology.

Low-voltage, high-speed circuit designs for gigabit DRAMs

This paper describes several new circuit design techniques for low V/sub CC/ regions: 1) a charge-amplifying boosted sensing (CABS) scheme which amplifies the sensing voltage difference (/spl Delta/V/sub BL/) as well as the V/sub GS/ margin by boosting the sensing node voltage with a voltage dependent boosting capacitor and 2) an I/O current sense amplifier with a high gain using a cross-coupled current mirror control scheme and reduced temperature sensitivity using a simple temperature-compensation scheme. An experimental 16 Mb DRAM chip with the 0.18-/spl mu/m twin-well, triple-metal CMOS process has been fabricated, and an access time from the row address strobe (t/sub RAC/) of 28 ns at V/sub cc/=1.5 V and T=25/spl deg/C has been obtained.

A 32-bank 1 Gb DRAM with 1 GB/s bandwidth

This 32-bank 1 Gb DRAM features: (1) a merged bank architecture (MBA) that results in only 3% die area penalty for 32-bank operation; (2) a source-synchronous I/O interface (SSI) that achieves 1 GB/s bandwidth with low power consumption; (3) flexible block redundancy that allows freedom of repair to anywhere within each half-Gb array; and (4) extended small swing read and single-I/O line driving write which result in 30% power reduction. The DRAM chip is implemented in a 0.16 /spl mu/m twin-well CMOS process.

A 2.5-V, 72-Mbit, 2.0-GByte/s packet-based DRAM with a 1.0-Gbps/pin interface

A 2.5-V, 72-Mbit DRAM based on packet protocol has been developed using (1) a rotated hierarchical I/O architecture to reduce power noise and to minimize the chip-size penalty associated with an 8-bit prefetch architecture implemented with 16 internal banks and 144 I/O lines, (2) a delay-locked-loop circuit using a high-speed and small-swing differential clock to achieve the peak bandwidth of 2.0 GByte/s in a single chip with low noise sensitivity, and (3) a flexible column redundancy scheme to efficiently increase redundancy coverage using a shifted I/O line scheme for multibank architecture.

Low voltage high speed circuit designs for giga-bit DRAMs

An experimental 16 Mb DRAM for giga scale densities with a charge-amplifying boosted sensing (CABS) scheme and a new I/O large gain current sense amplifier using a cross-coupled current mirror control scheme achieves a t/sub RAC/ of 28 ns and an average operating current of 22 mA at V/sub CC/=1.5 V, t/sub RC/=70 ns, T=25/spl deg/C. This chip has been fabricated using a 0.18 /spl mu/m twin-well CMOS process with KrF lithography having transistor channel lengths of 0.32(n)/0.40(p)/spl mu/m and low resistance TiSi/sub 2/ wordlines.

An area-efficient 2 GB/s 256 Mb packet-based DRAM with daisy-chained redundancy scheme

An area-efficient packet-based 256 Mb DRAM with a 4 bank architecture and a peak bandwidth of 1.0 Gbps/pin at V/sub cc/=2.35 V, Temp=100/spl deg/C is developed. This chip features a daisy chained redundancy scheme, an area-efficient logic block placement and routing technique and a process insensitive DLL with duty error reduction scheme to overcome large chip size penalty and to improve chip yield.

A 2.5 V, 2.0 GByte/s packet-based SDRAM with a 1.0 Gbps/pin interface

A 2.5 V, 72 Mbit packet protocol based SDRAM (PSDRAM) achieving a peak bandwidth of 2.0 GByte/s has been developed with a 0.23 /spl mu/m twin-well, 4-poly, 2-metal CMOS process. An internal Vcc of 2.0 V and V/sub term/ of 1.8 V with 0.8 V signal swing are used in the array to reduce the sensing power and I/O switching power, respectively. The total maximum chip power consumption of 1.80 W, including the average I/O switching power of 0.25 W, has been achieved when internal 16 banks are interleavingly operated with 20 ns interval commands at 2.0 GByte/s, Vcc=2.7 V, and T=25/spl deg/C.