
Signal processing circuit for 2-D PSD
C4674, C4757, C4758, C7563
The followings are obtained with the conditions listed
on the left.
Output voltage amplitude
V
FS
(X)=±6 V
V
FS
(Y)=±6 V
x=0.1 μm approx.
y=0.1 μm approx.
Position resolution
(calculated values)
I
Absolute maximum ratings
DC circuit
C4757
AC circuit
C7563
Parameter
Symbol
C4674
C4758
Unit
Supply voltage
Input current
Output short-circuit time
Operating temperature
Transistor collector-emitter voltage
Transistor collector current *
3
Transistor collector dissipation *
3
Vcc Max.
I
IN
Max.
-
Topr
V
CE
I
C
Pc
±18
V
A
s
°
C
V
A
mW
Vcc Max. × 10
-5
Continuous
0 to +50
-
-
-
Signal
processor
-
-
-
-
-
-
+50
2
900
LED driver
I
Specifications (Ta=25
°
C, Vcc=
±
15 V)
Typical value
DC circuit
C4757
1 × 10
5
100
AC circuit
C7563
Parameter
Symbol
Condition
C4674
C4758
Unit
Head-amp conversion impedance
*
4
Feedback capacitance
Rf
Cf
Factory setup prior to shipping
Factory setup prior to shipping
Photocurrent with PSD
installed
Output response time
versus movement of light
spot position, measured
with PSD installed.
-
*
7
With PSD installed and
light spot falling on edge
of active area.
All range *
7
*
7
*
3
*
8
V/A
pF
22
Input signal current
*
5
I
IN
1 × 10
-5
to 1 × 10
-4
A
Rise time
tr
30
μs
PSD reverse bias voltage
Output offset voltage
V
R
V
OS
+5
V
-10 to +10
mV
Output voltage amplitude *
6
Vo
-10 to +10
V
Output noise (analog divider)
Current consumption
Transistor collector current
Repetition frequency
Vn
Icc
Ic
f
T
5
10
±60
680
333
Open
collector
mVp-p
mA
mAp-p
Hz
Signal
processor
±15
-
-
-
-
-
-
LED
driver
Output type
-
-
-
-
-
-
*3: Duty ratio: 3/100, pulse width: 90 μs, LED: Hamamatsu L1915-01 (sold separately)
*4: These resistors are lead types and inserted into sockets, so it can be easily to exchange by the user if necessary in a range
between 1 × 10
4
to 1 × 10
6
. For more details, see the instruction manual that comes with the product.
*5: The circuit does not operate correctly when input signal level is not appropriate.
*6: Maximum output amplitude can be adjusted in a range of ±2 to ±10 V according to PSD type to be used.
*7: Measured without PSD and with LED turned off, while using a current source of 20 μA (X1=X2=Y1=Y2) substituting for PSD
photocurrent. In the case of C7563, however, pulse current with a duty ratio of 3/100 and a pulse width of 90 μs is supplied.
*8: Repetition frequency 333 Hz (duty ratio: 3/100, pulse width: 90 μs) cannot be modulated.
I
Operating example (C4674)
Constant voltage power supply: ±15 V, Power capacity: 0.1 A Min.
Ripple voltage: 3 mVp-p Max.
SIGNAL
PROCESSING CIRCUIT
C4674
2-D
PSD
REGULATED
POWER
SUPPLY *
VOLTMETER
VOLTMETER
+15 V
0 V
-15 V
+V
GND
-V
Xout
+
GND
-
Yout
+
GND
-
Y
2
X
2
V
R
Y
1
X
1
3
5
4
1
2
2
KPSDC0034ED
Condition
1. Light source
2. Light spot diameter
3. PSD used
4. PSD photocurrent
5. Signal processing circuit
6. Frequency bandwidth
7. Voltmeter
LED (
λ
=900 nm)
φ
200 μm
S1880 (12 × 12 mm)
10 μA
C4674
10 Hz
KEITHLEY model 195 A