Features: Differential clock signals.
Meets SSTL_2 class II specifications on outputs.
Low voltage operation: VDD = 2.3V to 2.7V.
Available in 64-pin TSSOP, 64-pin TVSOP, and 56-pin VFQFN packages.Application• JEDEC and Non-JEDEC DDR Memory Modules
• Stacked or Planar configurations.
• Supports PC1600 - PC2100 - PC2700 - PC3200
• DDR 400 compliant (200MHz+).
• SSTL_2 I/O.
• Provides a complete support solution for JEDEC JC42.5 DIMMs' when used with the ASM5CVF857 Zero Delay Buffer.PinoutSpecifications
Parameter |
Min |
Max |
Unit |
Storage Temperature |
-65 |
+150 |
°C |
Supply Voltage |
-0.5 |
3.6 |
V |
Input Voltage1 |
-0.5 |
VDD + 0.5 |
V |
Output Voltage1,2 |
-0.5 |
VDD + 0.5 |
V |
Input Clamp Current |
± 50 |
mA |
Output Clamp Current |
±50 |
mA |
Continuous Output Current |
±50 |
mA |
VDD, VDDQ or GND current/pin |
100 |
mA |
Package Thermal Impedance3 |
55 |
°C/W |
Note: 1. The input and output negative voltage ratings may be excluded if the input and output clamp ratings are observed. 2. This current will flow only when the output is in the high state level V0 > VDDQ. 3. The package thermal impedance is calculated in accordance with JESD 51. These are stress ratings only and functional operation is not implied. Exposure to absolute maximum ratings for prolonged periods can affect device reliability. |
DescriptionThe ASM4SSTVF16859 is a universal 13/26 bit register (D F/F based), designed for 2.3V to 2.7V VDD operation. The device supports SSTL_2 I/O levels, and is fully compliant with the JEDEC JC40, JC42.5 DDR I specifications covering PC1600, PC 2100, PC2700, and PC3200 operational ranges ( DDR 400 200 MHz ). 13/26 bits of ASM4SSTVF16859 refers to 2Q outputs for each D input - designed for use in Stacked Registered (stacked Memory Devices), Buffered DIMM applications.
Data flow of ASM4SSTVF16859 from D to Q is controlled by the differential clock (CLK/CLKB) and a control signal (RESETB). The positive edge of CLK is used to trigger the data transfer, and CLKB is used to maintain sufficient noise margins, whereas RESETB input is designed and intended for use at power-up.
The ASM4SSTVF16859 supports a low power standby mode of operation. A logic level low at RESETB, assures that all internal registers and outputs (Q) are reset to a logic low state, and that all input receivers, data (D) buffers, and clock (CLK/CLKB) are switched off. Note that RESETB ASM4SSTVF16859 should be supported with a LVCMOS level at a valid state since VREF may not be stable during power-up.
To ensure that outputs of ASM4SSTVF16859 are at a defined logic state before a stable clock has been supplied, RESETB must be held at a logic low level during power-up.
In the JEDEC defined Registered DDR DIMM application, RESETB is specified to be asynchronous with respect to CLK/CLKB; therefore, no timing relationship can be guaranteed between the two signals. When entering a low-power standby state, the register will be cleared and the outputs will be driven to a logic low level quickly relative to the time to disable the differential input receivers. This ensures there are no "glitches" on any output. However, when coming out of low power standby mode, the register will become active quickly relative to the time taken to enable the differential input receivers. When the data inputs are at a logic level low and the clock is stable during the low-to-high transition of RESETB until the input receivers are fully enabled, the design ensures that the outputs will remain at a logic low level.