MSC8254_11 Datasheet, PDF (26/68 Pages) Freescale Semiconductor, Inc – Quad-Core Digital Signal Processor

Electrical Characteristics
2.5 DC Electrical Characteristics
This section describes the DC electrical characteristics for the MSC8254.
2.5.1 DDR SDRAM DC Electrical Characteristics
This section describes the DC electrical specifications for the DDR SDRAM interface of the MSC8254.
Note: DDR2 SDRAM uses V_DDDDR(typ) = 1.8 V and DDR3 SDRAM uses V_DDDDR(typ) = 1.5 V.
2.5.1.1 DDR2 (1.8 V) SDRAM DC Electrical Characteristics
Table 6 provides the recommended operating conditions for the DDR SDRAM controller when interfacing to DDR2 SDRAM.
Note: At recommended operating conditions (see Table 3) with V_DDDDR = 1.8 V.
Table 6. DDR2 SDRAM Interface DC Electrical Characteristics
Parameter/Condition
Symbol
Min
Max
Unit
Notes
I/O reference voltage
MV_REF
0.49 × V_DDDDR
0.51 × V_DDDDR
V
2, 3, 4
Input high voltage
V_IH
MV_REF + 0.125
V_DDDDR + 0.3
V
5
Input low voltage
V_IL
–0.3
MV_REF – 0.125
V
5
I/O leakage current
I_OZ
–50
50
μA
6
Output high current (V_OUT (VOH) = 1.37 V)
I_OH
–13.4
—
mA
7
Output low current (V_OUT (VOL) = 0.33 V)
I_OL
13.4
—
mA
7
Notes: 1. V_DDDDR is expected to be within 50 mV of the DRAM V_DD supply voltage at all times. The DRAM and memory controller can
use the same or different sources.
2. MV_REF is expected to be equal to 0.5 × V_DDDDR and to track V_DDDDR DC variations as measured at the receiver. Peak-to-peak
noise on MV_REF may not exceed ±2% of the DC value.
3. V_TT is not applied directly to the device. It is the supply to which far end signal termination is made and is expected to be equal
to MV_REF with a minimum value of MV_REF – 0.4 and a maximum value of MV_REF + 0.04 V. V_TT should track variations in the
DC-level of MV_REF.
4. The voltage regulator for MV_REF must be able to supply up to 300 μA.
5. Input capacitance load for DQ, DQS, and DQS signals are available in the IBIS models.
6. Output leakage is measured with all outputs are disabled, 0 V ≤ V_OUT ≤ V_DDDDR.
7. Refer to the IBIS model for the complete output IV curve characteristics.
MSC8254 Quad-Core Digital Signal Processor Data Sheet, Rev. 6
26
Freescale Semiconductor