The GDDR5 SGRAM is a high speed dynamic random-access memory designed for applications requiring high bandwidth. GDDR5 devices contain the following number of bits:


4Gb has 4,294,967,296 bits and sixteen banks

The GDDR5 SGRAM uses a 8n prefetch architecture and DDR interface to achieve high-speed operation. The device can be configured to operate in x32 mode or x16 (clamshell) mode. The mode is detected during device initialization. The GDDR5 interface transfers two 32 bit wide data words per WCK clock cycle to/from the I/O pins. Corresponding to the 8n-prefetch a single write or read access consists of a 256 bit wide, two CK clock cycle data transfer at the internal memory core and eight corresponding 32 bit wide one-half WCK clock cycle data transfers at the I/O pins.
The GDDR5 SGRAM operates from a differential clock CK and CK#. Commands are registered at every rising edge of CK. Addresses are registered at every rising edge of CK and every rising edge of CK#.
GDDR5 replaces the pulsed strobes (WDQS & RDQS) used in previous DRAMs such as GDDR4 with a free running differential forwarded clock (WCK/WCK#) with both input and output data registered and driven respectively at both edges of the forwarded WCK.
Read and write accesses to the GDDR5 SGRAM are burst oriented; an access starts at a selected location and consists of a total of eight data words. Accesses begin with the registration of an ACTIVE command, which is then followed by a READ or WRITE command. The address bits registered coincident with the ACTIVE command and the next rising CK# edge are used to select the bank and the row to be accessed. The address bits registered coincident with the READ or WRITE comm




•Single ended interface for data, address and command

•Quarter data-rate differential clock inputs CK/CK# for ADD/CMD

•Two half data-rate differential clock inputs WCK/WCK#, each associated with two data bytes (DQ, DBI#, EDC)

•Double Data Rate (DDR) data (WCK)

•Single Data Rate (SDR) command (CK)

•Double Data Rate (DDR) addressing (CK)

•16 internal banks

•4 bank groups for tCCDL = 3 tCK

•8n prefetch architecture: 256 bit per array read or write access

•Burst length: 8 only

•Programmable CAS latency: 5 to 20 tCK

•Programmable WRITE latency: 1 to 7 tCK

•WRITE Data mask function via address bus (single/double byte mask)

•Data bus inversion (DBI) & address bus inversion (ABI)

•Address training: address input monitoring by DQ pins

•WCK2CK clock training with phase information by EDC pins

•Data read and write training via READ FIFO

•READ FIFO pattern preload by LDFF command

•Direct write data load to READ FIFO by WRTR command

•Consecutive read of READ FIFO by RDTR command

•Read/Write data transmission integrity secured by cyclic redundancy check (CRC-8)

•READ/WRITE EDC on/off mode

•Programmable EDC hold pattern for CDR

•Programmable CRC READ latency = 0 to 3 tCK

•Programmable CRC WRITE latency = 7 to 14 tCK

•Low Power modes

•RDQS mode on EDC pin

•Optional on-chip with read-out

•Auto & self refresh modes

•Auto TCSR support

•Auto precharge option for each burst access

•32ms, auto refresh (16k cycles)

• controlled self refresh rate

•On-die termination (ODT); nominal values of 60 ohm and 120 ohm

•Pseudo open drain (POD-135 or POD-15) compatible outputs (40 ohm pulldown, 60 ohm pullup)

•ODT and output drive strength auto-calibration with external resistor ZQ pin (120 ohm)

•Programmable termination and driver strength offsets

•Selectable external or internal VREF for data inputs; programmable offsets for internal VREF

•Separate external VREF for address / command inputs

•Vendor ID, FIFO depth and Density info fields for identification

•x32/x16 mode configuration set at power-up with EDC pin

•Mirror function with MF pin

•Boundary scan function with SEN pin

•1.35V / 1.5V +/- (3%xVDD)V supply for device operation (VDD)

•1.35V / 1.5V +/- (3%xVDDQ)V supply for I/O interface (VDDQ)

•170 ball BGA package


SpeedSpeed의 Part Number, Voltage, Speed를 나타낸 표 입니다.
Part Number Speed Voltage
R0 3.0GHz/3.5GHz 1.35V/1.5V
T2 2.5GHz/3.0GHz 1.35V/1.5V