ML6633
FUNCTIONAL DESCRIPTION
The ML6633 accepts ECL input signals and generates a
high speed, high accuracy output current which is
independent of supply voltage variations. The output
current is programmable up to 82mA.
Output current to the LED is set by connecting the
appropriate resistance from RTSET to ground. The high
level output voltage at RTSET will be 2.0V. The current in
the external resistor will be equal to the current through
the LED. The output current with RTSET set to 26.1Wwill
be:
The ECL input stage is a standard NPN differential pair
with a common mode range of between 1V and 4.5V with
a +5V supply. With this common mode range it is possible
to convert the ECL inputs into TTL. If the ECLN input is
biased up to the TTL switching level, the ECLP pin can be
driven by a TTL or CMOS output. Figure 1b shows a circuit
implementing this technique. This circuit may degrade
pulse width distortion and should be checked for
2V
ILED (HIGH) =
ILED (HIGH) =
(1)
RTSET
2V
= 75mA
26.1Ω
acceptable performance in this configuration.
5V
5V
NC
V
CC
VIN+
VIN–
ECLP
ECLN
I
OUT
RTSET
GND
NC
a) I
= 75mA
OUT
5V
5V
5V
NC
V
CC
TTLIN
ECLP
ECLN
I
OUT
RTSET
GND
NC
b) ECL-to-TTL Conversion
Figure 1. Typical Applications
4
MICRO-LINEAR [ MICRO LINEAR CORPORATION ]
