DEFINITIONS
LINEARITY ERROR
OUTPUT LEAKAGE CURRENT
Linearity error is defined as the difference between the actual
current value for a given digital input setting and the current
value indicated by the straight line through point P
1
and P
15
.
The point P
1
is the current at the setting 1 (0001)
of the digital input. (Figure 13)
The point P
15
is the current at the setting 15
(1111) of the digital input (Figure 13)
The current at set 0(0000) of the digital input is left out of the
linearity error definition. This point on the characteristic is not
correlated to other points (there is no current commutation
through the current sink at set 0000).
CURRENT VALUE
P15
Maximum sink current of the control output at setting 0 of the
digital input is defined as output leakage current.
EARLY VOLTAGE
The early voltage is defined by the following equation:
V = Early Voltage =
a
1
channel length modulation
=
=
where
V
a
0.5 -
I
0.5
(0.5 - 0.7)
(I
0.5
-
I
0.7
)
- Early Voltage
I
0.5
- sink output current at bias voltage V
PCS
= 0.5 V
I
0.7
- sink output current at bias voltage V
PCS
= 0.7 V
MEASURED VALUES
LINEARITY
ERROR
OUTPUT
CURRENT
OFFSET
P1
0 1
2
3
4
5
6
7
8
9 10 11 12 13 14 15
DIGITAL SETTINGS
Fig. 13 PCS Current vs Digital Setting
OUTPUT CURRENT OFFSET FOR SETTING 0
The current value determined by the extrapolation of the
straight line (defined by the linearity error definition) at setting
0 (0000) of the digital input ( Figure 13) is defined as the ouput
current offset.
DOCUMENT IDENTIFICATION:
DATA SHEET
The product is in production. Gennum reserves the right to make
changes at any time to improve reliability, function or design, in
order to provide the best product possible.
REVISION NOTES:
Updated to Data sheet
Gennum Corporation assumes no responsibility for the use of any circuits described herein and makes no representations that they are free from patent infringement.
© Copyright April 1991Gennum Corporation.
All rights reserved.
Printed in Canada.
510 - 79 - 06
8
GENNUM [ GENNUM CORPORATION ]
