HBCS-1100 Datasheet, PDF (2/7 Pages) Agilent(Hewlett-Packard) – High Resolution Optical Reflective Sensor

The sensor can be rigidly secured
by commercially available two
piece TO-5 style heat sinks, such
as Thermalloy 2205, or Aavid
Engineering 3215. These fixtures
provide a stable reference plat-
form and their tapped mounting
holes allow for ease of affixing
this assembly to the circuit board.
Electrical Operation
The detector section of the
sensor can be connected as a
single photodiode or as a
photodiode transistor amplifier.
When photodiode operation is
desired, it is recommended that
the substrate diodes be defeated
by connecting the collector of the
transistor to the positive potential
of the power supply and shorting
the base-emitter junction of the
transistor. Figure 15 shows
photocurrent being supplied from
the anode of the photodiode to an
inverting input of the operational
amplifier. The circuit is recom-
mended to improve the reflected
photocurrent to stray photocur-
rent ratio by keeping the
substrate diodes from acting as
photodiodes.
The cathode of the 700 nm
emitter is physically and
electrically connected to the case-
substrate of the device. Applica-
tions that require modulation or
switching of the LED should be
designed to have the cathode
connected to the electrical
ground of the system. This
insures minimum capacitive
coupling of the switching
transients through the substrate
diodes to the detector amplifier
section.
The HBCS-1100 detector also
includes an NPN transistor which
can be used to increase the
output current of the sensor. A
current feedback amplifier as
shown in Figure 6 provides
moderate current gain and bias
point stability.
Schematic Diagram
Connection Diagram
REFERENCE
PLANE
V_D
V_C
3
1
REFLECTOR
ANODE
V_F ⁶
CATHODE ₄
SUBSTRATE, CASE
D_S – SUBSTRATE DIODES
D_S
D_S
2
8
V_B V_E
3
4
2
5
1
TOP VIEW
6
8
7
PIN
FUNCTION
1 TRANSISTOR COLLECTOR
2 TRANSISTOR BASE, PHOTODIODE ANODE
3 PHOTODIODE CATHODE
4 LED CATHODE, SUBSTRATE, CASE
5 NC
6 LED ANODE
7 NC
8 TRANSISTOR EMITTER
CAUTION: The small junction sizes inherent to the design of this bipolar component increase the component's
susceptibility to damage from electrostatic discharge (ESD). It is advised that normal static precautions be
taken in handling and assembly of this component to prevent damage and/or degradation which may be
introduced by ESD.
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