iC-PD3948
5-CH. PHASED ARRAY SINE ENCODER (39-2048)
Rev B5, Page 2/10
DESCRIPTION
iC-PD3948 is an optical sensor IC with integrated All code disc signal tracks are evaluated differentially;
photodiodes whose signal currents are converted the high resolution sine signals are read by photo-
into output voltages by low-noise transimpedance diodes in a phased array. The layout of the signal
amplifiers.
amplifiers is such that there is good paired channel
matching, reducing the time and effort required for
Due to a high transimpedance gain of typically calibration to an absolute minimum.
4 MΩ, output signal voltages of several hundred Mil-
livolts are obtained at illumination levels of just 1 to The spectral sensitivity ranges from visible to near
3 mW/cm2. In most cases complicated noise sup- infrared light, with the maximum sensitivity close to
pression measures are thus rendered unnecessary.
a wavelength of 680 nm. An output voltage of 1 V
is typical in low light conditions, for instance when iC-
As the pin names would suggest, iC-PD3948 is typ- PD is illuminated at only 2 mW/cm2 by a 740 nm LED.
ically applied as a sine encoder for motor feedback A relatively low LED current is enough to operate the
systems. To this end, iC-PD3948 provides sine and sensor, proving beneficial to the life expectancy of the
cosine signals with both a high resolution of 2048 LED at high operating temperatures.
PPR (plus an additional index signal) and a low res-
olution of 1 PPR (at C/D).
PACKAGES AND CHIP LAYOUT INFORMATION
PAD LAYOUT (2.88 mm x 3.37 mm)
PAD FUNCTIONS
No. Name Function
1 VCC +4.5...5.5 V Supply Voltage
2 VREF Reference Voltage Output
3 PSIN Sine Track +
4 NSIN Sine Track -
5 PCOS Cosine Track +
6 NCOS Cosine Track -
7 Z
8 NZ
Z Index Signal
Z Index Track -
9 ND
10 PD
11 NC
12 PC
D Track -
D Track +
C Track -
C Track +
13 VRDC D/C Track Reference
14 VRSC S/C Track Reference
15 GND Ground
Notes: All outputs are analog voltage
outputs.
ICHAUS [ IC-HAUS GMBH ]
