RO0064N

The RO0064N has the following features including 64 elements equally spaced on a 2 mm diameter drde;0.1 mm x 0.1 mm individual element size;Charge storage mode operation for high sensitivity;Integrated ring counter scanning circuit;Requires simple drive and output circuitry;Wide range of clock rates-2kHz to 2.5kHz;30 to 40,000 complete circular scans per second;Standard 16 lead dual-in-line package with sealed glass window.

The RO0064N is the first self-scanned photodiode array available in a circular configuration. The device will find application in such fields as tracking, alignment, pattern recognition, inspection, and automatic focusing. The RO0064N is a monolithic array of Ei4 silicon photo-diodes uniformly spaced on a circle 2 mm in diameter. The array is self-scanned In a clockwise direction by an integrated 84 stage ring counter. The diodes operate In the charge storage mode, i.e, they integrate photocurrent for an entire circular scan period. During each scan the charge on each of the 64 diodes Is read-out sequentially onto a single output line.The read-out rate is set by the frequency of the complimentary square wave clocks which are required to drive the ring counter. A sync pulse output is provided once each scan at a reference point on the circle.Good clods drivers are essential In order to minimize switching noise in the video output and to obtain maximum performance at high scan rates. The clocks should have very fast rise and fall times with the rising edge of one phase matching the falling edge on the other phase. A recommended drive circuit is shown in Figure 7 and the clock waveforms are shown in the liming diagram of figure 8.

In the specifications, all voltages are expressed with respectto array common. However, for compatibility with TTL clocks and ease of signal extraction, It is recommended that commonbe run at plus 5 volts. The clock phases should then swing between plus 5 and minus 8 to minus 10 volts.Spectrtral response of the RO0064N is typical of high quality diffused silicon photodiodes, extending from the near UV to the near IR. A glass window is standard: however, an optional quartz window is available. Relative response is shown as a function of wavelength in Figure 8.