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9–2 Electrical Data
Alpha 21264/EV67 Hardware Reference Manual
DC Characteristics
9.2 DC Characteristics
This section contains the dc characteristics for the 21264/EV67. The 21264/EV67 pins
can be divided into 10 distinct electrical signal types. The mapping between these sig-
nal types and the package pins is shown in Chapter 3. Table 9–2 shows the signal types.
Tables 9–3 through 9–12 show the dc switching characteristics of each signal type.
Also, the following notes apply to Tables 9–3 to 9–12.
1. The differential voltage, Vdiff, is the absolute difference between the differential
input pins.
2. Delta V
BIAS
is defined as the open-circuit differential voltage on the appropriate
differential pairs. Test condition for these inputs are to let the input network self
bias and measure the open circuit voltage. The test load must be ≥ 1M ohm. In nor-
mal operation, these inputs are coupled with a 680-pF capacitor.
3. Functional operation of the 21264/EV67 with less than all VDD and VSS pins con-
nected is not implied.
4. The test load is a 50-ohm resistor to VDD/2. The resistor can be connected to the
21264/EV67 pin by a 50-ohm transmission line of any length.
5. DC test conditions set the minimum swing required. These dc limits set the trip
point precision.
6. Input pin capacitance values include 2.0 pF added for package capacitance.
Table 9–2 Signal Types
Signal Type Description
I_DC_POWER Supply voltage pins (VDD/PLL_VDD)
I_DC_REF Input dc reference pin
I_DA Input differential amplifier receiver
I_DA_CLK Input differential amplifier clock receiver
O_OD Open-drain output driver
O_OD_TP Open-drain driver for test pins
O_PP Push-pull output driver
O_PP_CLK Push-pull output clock driver
B_DA_OD Bidirectional differential amplifier receiver — open-drain
B_DA_PP Bidirectional differential amplifier receiver — push-pull