Previous Design WorkPrevious Design Work

Zeynep DilliZeynep Dilli

dilli@eng.umd.edudilli@eng.umd.edu

Some Design ProjectsSome Design Projects

Optical System Design: A Borescope Optical System Design: A Borescope (ENEE 408E)(ENEE 408E)Electronics Circuit Design: AM Radio Electronics Circuit Design: AM Radio System (ENEE 719)System (ENEE 719)Chip Design: Parasitic Load Chip Design: Parasitic Load Measurements (research work)Measurements (research work)

Others: An Optical Keyboard, A Pulse Width Modulator, Others: An Optical Keyboard, A Pulse Width Modulator, An External Cavity Laser (undergraduate and previous An External Cavity Laser (undergraduate and previous research work)research work)

Borescope DesignBorescope Design

BorescopeBorescope: : An optical device used to examine An optical device used to examine narrow and inaccessible spaces, e.g. inside a gun narrow and inaccessible spaces, e.g. inside a gun barrel or engine cylinderbarrel or engine cylinder

Specifications:Specifications: Diameter <25 mm; cost Diameter <25 mm; cost <$1000; design for a CCD camera as an <$1000; design for a CCD camera as an eyepiece; image acceptance angle ±25º; periodic eyepiece; image acceptance angle ±25º; periodic relay system to ensure extensibility.relay system to ensure extensibility.

Design decisions:Design decisions: Lenses w/ diameter <15 Lenses w/ diameter <15 mm; commercial lenses from Melles-Griot; aim for mm; commercial lenses from Melles-Griot; aim for a focused image to be aligned with focal lens of a a focused image to be aligned with focal lens of a CCD camera.CCD camera.

Borescope SectionsBorescope SectionsObjective:Objective: Achromatic doublets to Achromatic doublets to create a well-focused image of an create a well-focused image of an object close to the lens with a object close to the lens with a wide angle.wide angle.Field Lens:Field Lens: Refocus the rays to Refocus the rays to make propagation direction more make propagation direction more axial.axial.

Relay System: Relay System: Carry the image Carry the image long distances without extra long distances without extra distortion.distortion.

ObjectiveObjective Field LensField Lens

•This is 25 cm long. Adding relay units it can be extended to 34 cm, 43 cm…This is 25 cm long. Adding relay units it can be extended to 34 cm, 43 cm…

AM Radio AM Radio Radio receiver/demodulator in the AM range:Radio receiver/demodulator in the AM range: c between approximately 500 kHz and 1500kHzbetween approximately 500 kHz and 1500kHz

IFIF at AM standard, 455 kHzat AM standard, 455 kHz

LOLO then has to vary between 955 kHz and 1955 kHzthen has to vary between 955 kHz and 1955 kHz

AM Radio Frequency Domain AM Radio Frequency Domain Operation-1Operation-1

•AM-Modulated signalAM-Modulated signal

•After the LO Mixer---the LO operatingAfter the LO Mixer---the LO operating

frequency is what we tune; frequency is what we tune; LO-LO-c=c=IF IF

where where c is the carrier frequency.c is the carrier frequency.

•After the IF filterAfter the IF filter

AM Radio Frequency Domain AM Radio Frequency Domain Operation-2Operation-2

•After IF amplificationAfter IF amplification

•After IF MixerAfter IF Mixer

•After the LPF---Audio-frequency signal.After the LPF---Audio-frequency signal.

AM Radio Time Domain OperationAM Radio Time Domain Operation

Chip DesignsChip Designs

•Objective: Measure Objective: Measure loading effects of loading effects of bonding padsbonding pads

Effect of Pads—Test SetupEffect 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.

Effect of Pads—Results SummaryEffect of Pads—Results Summary

Internal Osc.Internal Osc. External Osc.External Osc. One-stage delayOne-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

0.6 m chip, measurements taken by Tektronix oscilloscope with 1 pF-capacitance active probe on the breadboard

Speed ratio: 794.5Load ratio: ~1000

3-D Integration: “Symmetric” Chip3-D Integration: “Symmetric” Chip

Chip with structures that can be connected in 3D and planar counterparts for comparison

3-D Connections: “Symmetric” Chip3-D Connections: “Symmetric” Chip

Same 31-stage planar ring oscillator with counter outputAlso 31-stage 3-D ring oscillator with counter output(On the figure, groups of 5-5-5-5-5-6).

To counter input

Simulation results:

Planar: 142 MHz3-D, six “layer”s: 122 MHz

“symmetry” axis

The proper pairs of pads have to be connected to each other through vertical through-chip vias post-fabrication for the circle to close.