preliminary

preliminary

iC-PD3948

5-CHAN. PHASED ARRAY SINE ENCODER 39-2048

Rev B4, Page 2/9

DESCRIPTION

iC-PD3948 is an optical sensor IC with integrated

photodiodes whose signal currents are converted

into output voltages by low-noise transimpedance

amplifiers.

Due to a high transimpedance gain of typically

4 MΩ, output signal voltages of several hundred Mil-

livolts are obtained at illumination levels of just 1 to

pression measures are thus rendered unnecessary.

As the pin names would suggest, iC-PD3948 is typ-

ically applied as a sine encoder for motor feedback

systems. To this end, iC-PD3948 provides sine and

cosine signals with both a high resolution of 2048

PPR (plus an additional index signal) and a low res-

olution of 1 PPR (at C/D).

All code disc signal tracks are evaluated differentially;

the high resolution sine signals are read by photo-

diodes in a phased array. The layout of the signal

amplifiers is such that there is good paired channel

matching, reducing the time and effort required for

calibration to an absolute minimum.

The spectral sensitivity ranges from visible to near

infrared light, with the maximum sensitivity close to

a wavelength of 680 nm. An output voltage of 1 V

is typical in low light conditions, for instance when iC-

A relatively low LED current is enough to operate the

sensor, proving beneficial to the life expectancy of the

LED at high operating temperatures.

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

Z Index Signal

8 NZ

Z Index Track -

9 ND

D Track -

10 PD

D Track +

11 NC

C Track -

12 PC

C Track +

13 VRDC D/C Track Reference

14 VRSC S/C Track Reference

15 GND

Ground

Notes: All outputs are analog voltage

outputs.