S1K50000 Epson Electronics America, Inc., S1K50000 Datasheet - Page 93

• Manufacturer Part Number: S1K50000
• Description: Design Guide S1k50000 Series
• Manufacturer: Epson Electronics America, Inc.

Chapter 8: Pin Arrangement and Simultaneous Operation
Chapter 8 Pin Arrangement and Simultaneous
8.1 Estimating the Number of Power-Supply Pins
8.2 Simultaneously Operating Buffers and Added Power Supply
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The necessary number of power-supply pins must be estimated based on the LSI’s power
consumption and the number of output buffers. In particular, the output buffers conduct a
large amount of transient current when switched. This transient current tends to increase as
the output buffer’s drive capability increases.
Regarding the number of power-supply pins required for the LSI, the following applies with
respect to current consumption.
For details on how to estimate the number of power-supply pins in a dual-power-supply
system, see Chapter 9, “Precautions on the Use of Dual Power Supplies.”
The S1K50000-series cells have a large output drive capability of up to 12 mA. As a
result, the output buffers generate a large amount of noise during operation, and an
extremely large amount during simultaneous operation.
If a large number of output buffers are operated simultaneously in your application, add
power supplies to prevent noise-induced malfunction, as shown in Tables 8-1-1 through 8-
2-2.
Letting the current consumption be I
N
Note: If the output buffers have a DC load connected and a steadily flowing current, one or
IDD
N
, required for this current consumption, I
IDD
more power-supply pins must be added. For more information, contact Seiko Epson
or its distributor.
I
DD
Note: The number of power-supply pins in pairs, N
/50 (pair); 50 mA per pair of pins can be supplied
Operation
or more.
I
operating voltage.
DD
is the power consumption obtained in Chapter 7 divided by the
DD
EPSON
[mA], the number of power-supply pins in pairs,
DD
, is expressed by the equation shown below.
IDD
STANDARD CELL S1K50000 SERIES
, must at least be two pairs
DESIGN GUIDE