Previous Design Work

1. Previous Design Work Zeynep Dilli dilli@eng.umd.edu

2. Some Design Projects • Optical System Design: A Borescope (ENEE 408E) • Electronics Circuit Design: AM Radio System (ENEE 719) • Chip Design: Parasitic Load Measurements (research work) • Others: An Optical Keyboard, A Pulse Width Modulator, An External Cavity Laser (undergraduate and previous research work)

3. Borescope Design • Borescope: An optical device used to examine narrow and inaccessible spaces, e.g. inside a gun barrel or engine cylinder • Specifications: Diameter <25 mm; cost <$1000; design for a CCD camera as an eyepiece; image acceptance angle ±25º; periodic relay system to ensure extensibility. • Design decisions: Lenses w/ diameter <15 mm; commercial lenses from Melles-Griot; aim for a focused image to be aligned with focal lens of a CCD camera.

4. Borescope Sections Objective Field Lens • Objective: Achromatic doublets to create a well-focused image of an object close to the lens with a wide angle. • Field Lens: Refocus the rays to make propagation direction more axial. • Relay System: Carry the image long distances without extra distortion. This is 25 cm long. Adding relay units it can be extended to 34 cm, 43 cm…

5. AM Radio • Radio receiver/demodulator in the AM range: • c between approximately 500 kHz and 1500kHz • IF at AM standard, 455 kHz • LO then has to vary between 955 kHz and 1955 kHz

6. AM Radio Frequency Domain Operation-1 • AM-Modulated signal • After the LO Mixer---the LO operating frequency is what we tune; LO-c=IF where c is the carrier frequency. • After the IF filter

7. AM Radio Frequency Domain Operation-2 After IF amplification After IF Mixer After the LPF---Audio-frequency signal.

8. AM Radio Time Domain Operation

9. Chip Designs Objective: Measure loading effects of bonding pads

10. Effect of Pads—Test Setup Left: “External” ring oscillator, 11 stages (two stages are shown). Connection between stages require going out to the board through bonding pads, wires and pins. Both are comprised of minimum-size transistors, simulated speed for 31 stages: 132 MHz. Below: Internal ring oscillator, 31 stages, output to divide-by-64 counter. Direct connection between stages.

11. Internal Osc. External Osc. One-stage delay 112 MHz (31-stage) (equivalent to 1.16 GHz for 3 stages) 398 KHz (11-stage) (equivalent to 1.46 MHz for 3 stages) ~330 ps for internal, ~330 ns for external devices Effect of Pads—Results Summary 0.6 m chip, measurements taken by Tektronix oscilloscope with 1 pF-capacitance active probe on the breadboard Speed ratio: 794.5 Load ratio: ~1000

12. 3-D Integration: “Symmetric” Chip Chip with structures that can be connected in 3D and planar counterparts for comparison

13. 3-D Connections: “Symmetric” Chip Same 31-stage planar ring oscillator with counter output Also 31-stage 3-D ring oscillator with counter output (On the figure, groups of 5-5-5-5-5-6). The proper pairs of pads have to be connected to each other through vertical through-chip vias post-fabrication for the circle to close. Simulation results: Planar: 142 MHz 3-D, six “layer”s: 122 MHz To counter input “symmetry” axis