Philips PM2517X - Page 61

56
3.4.7.
OO 0063
Programmable
Current
Source
3.4.7.1.
General
The
OO 0063
can
deliver
5
programmable
currents
in the
range
1
mA
'10
nA
with
decade
steps'
The OO
0063
consist
of three
main
parts:
a reference current
source, two current
multipliers
and an
independent
operational
amplifier'
The
reference
current
source
can
be
adjusted
to
10
!A'
The current
multipliers
together
give
a multiplication
range
of
1/100'
1l10'
1
'
10' 100
dependent
to the
digital
input code.
The
op-amp
is independent
of
the current
part
and
is used
for compensation
and
protectlon'
r_
-t
*-1
I
-t
-l
v
-
r'
a
L-
-
L
['
._t
a:
I
t-'
I
t,
I
L
(
t"
t'
L-
Cs
(-8.5v)
RNG B
V
OUT
C COMP
Cs
CND
(+8
sv
)
RNG
A
RNG C
Fis.37.
t,
Vss GND
vda
-85v '85v