TI380FPA Datasheet, PDF (6/24 Pages) Texas Instruments – PACKETBLASTER™

TI380FPA
PACKETBLASTERā
SPWS011A − MARCH 1995 − REVISED AUGUST 1995
Pin Functions (Continued)
PIN
NAME
NO.
I/O†
DESCRIPTION
Local-memory write. MW is used to specify a write cycle on the local-memory bus. The data on the
MADH0 −MADH7 and MADL0 −MADL7 buses is valid while MW is low. DRAMs latch data on the falling
MW
24
O
edge MW, while SRAMs latch data on the rising edge of MW.
H = Not a local memory-write cycle
L = Local memory write-cycle
NC
33
42
No connect. Do not connect these pins.
PLLCAP
45
I
Phase-locked loop (PLL) tuning capacitor (see Note 3).
VDDL
17
36
I
Positive-supply voltage for digital logic. All VDDL pins must be attached to the common-system
power-supply plane.
VDD
3
16
29
I
Positive-supply voltage for output buffers. All VDDL pins must be attached to the common-system
power-supply plane.
PLLVDD
VSSC
46
I
Positive-supply voltage for phase-locked loop (see Note 4).
1
14
27
I
Ground reference for output buffers (clean ground). All VSSC pins must be attached to the
common-system-ground plane.
VSSL
11
40
I
Ground reference for digital logic. All VSSL pins must be attached to the common-system-ground plane.
VSS
12
25
51
I
Ground connections for output buffers. All VSS pins must be attached to common-system-ground
plane.
PLLVSS
44
I
Ground reference for phase-locked loop. Attach to the common-system-ground plane.
† _{I = input, O = output}
NOTES: 2. Pin has an internal pullup device to maintain a high-voltage external level when left unconnected. Alternatively, both pins tied
together can be pulled high through a single 4.7-Ω pullup resistor.
3. The PLLCAP requires the following connection:
These components must be placed as close as
possible to PLLCAP.
PLLCAP
1 kΩ
GND
0.1 µF
4. Isolate PLLVDD to a separate PLL power pad with
ferrite bead separation from the common-system
power-supply plane. A 0.1-µF decoupling capacitor
on PLLVDD is also necessary as shown. These
components must be placed as close as possible to
PLLVDD.
PLLVDD
GND
VDD
0.1 µF
6
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