Abstract: A portable electronic device may have a sealed connector secured within a device housing. The sealed connector may have a metal shell. A plastic contact housing may be insert molded within the shell. Conductive signal contacts may be laterally spaced in the contact housing. An elastomeric gasket may be assembled or compression molded onto the metal shell. Left and right metal brackets may be welded onto the metal shell to moisture-seal latch windows. A water-resistant sealing layer may be attached to the bottom plate of the metal shell to moisture-seal alignment rail windows. The sealed connector may be pressed against the device housing to place the gasket in a compressed state. The connector may be secured to the device housing by screwing down the metal brackets to a circuit board assembled within the housing while the gasket is in the compressed state.

Abstract: Mixed gate varactors are provided. The mixed gate varactors may include a semiconductor region of a given doping type. A first terminal for the varactor may be formed from a gate structure on the semiconductor region. A second terminal for the varactor may be formed from a heavily doped region in the semiconductor region that has the same doping type as the given doping type. A third terminal for the varactor may be formed from a heavily doped region in the semiconductor region that has a different doping type than the given doping type. The gate structure may include multiple gate conductors on a gate insulator. The gate insulator may be a high-K dielectric. The gate conductors may be metals or other materials that have different work functions. A conductive layer such as a layer of polysilicon may electrically connect the first and second gate conductors.

Abstract: Configurable time-borrowing flip-flops are provided for circuits such as programmable logic devices. The flip-flops may be based on a configurable delay circuit and two latches or may be based on a configurable pulse generation circuit and a single latch. In designs based on two latches, a first and a second latch are arranged in series. A clock signal is delayed using a configurable delay circuit. Programmable memory elements that have been loaded with configuration data may be used to adjust how much delay is produced by the configurable delay circuit. The delayed version of the clock signal is provided to a clock input associated with the first latch. The second latch has a clock input that receives the clock signal without delay. In designs based on a single latch, a configurable pulse generation circuit receives a clock signal for the flip-flop and generates a corresponding clock pulse for the latch.

Abstract: Slot antennas are provided for electronic devices such as portable electronic devices. The slot antennas may have a dielectric-filled slot that is formed in a ground plane element. The ground plane element may be formed from part of a conductive device housing. The slot may have one or more holes at its ends. The holes may affect the impedance characteristics of the slot antennas so that the length of the slot antennas may be reduced. For example, the holes can be used to synthesize the impedance of the slot antennas so that the slot antennas have a resonant frequency that is different from their natural resonant frequency. The holes may affect the impedance of the slot antennas in multiple radio-frequency bands.

Abstract: Electronic devices and accessories are provided that may communicate over wired communications paths. The electronic devices may be portable electronic devices such as cellular telephones or media players and may have audio connectors such as 3.5 mm audio jacks. The accessories may be headsets or other equipment having mating 3.5 mm audio plugs and speakers for playing audio. Microphones may be included in an accessory to gather voice signals and noise cancellation signals. Analog-to-digital converter circuitry in the accessory may digitize the microphone signals. Digital voice signals and voice noise cancellation signals can be transmitted over the communications path and processed by audio digital signal processor circuitry in an electronic device. Digital-to-analog converter circuitry in the accessory may convert digital audio signals to analog speaker signals.

Abstract: Electronic device antennas with multiple parallel plate sectors are provided for handling multiple-input-multiple-output wireless communications. Each antenna sector in a multisector parallel plate antenna may have upper and lower parallel plates with curved outer edges and a straight inner edge. A vertical rear wall may be used to connect the upper and lower parallel plates in each antenna sector along the straight inner edge. Each antenna sector may have an antenna probe. The antenna probe may be formed from a monopole antenna loaded with a planar patch. The planar loading patch may be provided in the form of a conductive disk that is connected to the end of a conductive antenna feed member. The conductive member may be coupled to the center conductor of a transmission line that is used to convey radio-frequency signals between the antenna probe and radio-frequency transceiver circuitry. The antenna sectors may have interplate dielectric structures.

Abstract: Integrated circuits with memory elements are provided. The memory elements may be arranged in a memory block. The memory block may include cross-coupled inverters that store data. The stored data may be used to program pass transistors. Transistors in the memory block may be stressed. Depending on the type of stress-inducing layer used, a tensile stress or a compressive stress may be built in into the transistors. Stressed transistors may help improve the routing speed of the memory block. Stressed transistors may be implemented using dual gate-oxide process.

Abstract: Electronic devices are provided that contain wireless communications circuitry. The wireless communications circuitry may have antenna diversity circuitry that allows an optimum antenna in an antenna structure to be switched into use during device operations. The antenna structure may be shared between multiple radio-frequency transceivers in a radio-frequency transceiver circuit. The radio-frequency transceiver circuit may be coupled to the antenna structure using switching and filtering circuitry. The filtering circuitry may include a diplexer that divides radio-frequency signals into a divided signal path based on frequency. The filtering circuitry may also include bandpass filters that are interposed in each branch of the divided signal path. Switching circuitry in the switching and filtering circuitry may be used to selectively configure the wireless communications circuitry in transmit and receive modes using multiple communications bands.

Abstract: Charge pump circuitry is provided that is insensitive to charge sharing and current mismatch effects. The charge pump circuitry has an output node at which a charge pump output voltage is provided. A first current source charges the output node to increase the output voltage or a second current source discharge the output node to decrease the output voltage. The charge pump circuitry uses a unit-gain op-amp circuit to prevent charge sharing effects from affecting the output voltage when switching between discharging and charging operations. A low-pass filter is used to reduce feedback noise on the output node. A replica feedback circuit prevents current mismatch between the currents produced by the first and second current sources. The first and second current sources may be formed using programmable transistors that are adjusted by static control signals provided by programmable elements to further minimize current mismatch.

Abstract: Electronic assemblies with solder containment brackets are provided. A solder containment bracket may have a planar base and a vertically extending wall. The wall may protrude upwards from the base to form an enclosed region. The base may have a hole that corresponds to the shape of the enclosed region. The wall may have an opening. A wire may be inserted into the opening. The wire may be soldered to the solder containment bracket to form a solder joint that electrically connects the wire to the bracket. The solder joint formed within the enclosed region may have a size that is defined by the bracket wall. The solder containment bracket may be soldered to a solder pad on a printed circuit board by reflowing a layer of solder paste.

Abstract: Keys may be formed for keyboards. The keyboards may be attached to electronic devices such as computers or may be formed within a portable computer or other electronic equipment. A keyboard may be provided with a planar housing member such as a top plate. The top plate may have openings through which key caps protrude. Each key cap may be attached to a respective spring mechanism. The spring mechanism for each key may have first and second diving-board structures that flex about respective parallel flex axes. A dome switch may be mounted under each spring mechanism. The dome switch is compressed when the key cap is pressed and the first diving-board structure moves towards the dome switch. The top plate may have edge portions surrounding each key opening that form upstop structures that prevent the key caps and spring mechanisms from tilting when the dome switch is compressed.

Abstract: Electronic devices are provided that contain wireless communications circuitry. The wireless communications circuitry may have antenna diversity circuitry that allows an optimum antenna or optimum antennas in an antenna structure to be switched into use during device operations. The antenna structure may be shared between multiple radio-frequency transceivers in a radio-frequency transceiver circuit. The radio-frequency transceiver circuit may be coupled to the antenna structure using switching and filtering circuitry. The filtering circuitry may include one or more diplexers that divide radio-frequency signals into divided signal paths based on frequency. The filtering circuitry may also include low pass, high pass, and bandpass filters that are interposed in the divided signal paths. Switching circuitry in the switching and filtering circuitry may be used to selectively configure the wireless communications circuitry in transmit and receive modes using multiple communications bands.

Abstract: Format-preserving encryption and decryption processes are provided. The encryption and decryption processes may use a block cipher. A string that is to be encrypted or decrypted may be converted to a unique binary value. The block cipher may operate on the binary value. If the output of the block cipher that is produced is not representative of a string that is in the same format as the original string, the block cipher may be applied again. The block cipher may be repeatedly applied in this way during format-preserving encryption operations and during format-preserving decryption operations until a format-compliant output is produced. Selective access may be provided to portions of a string that have been encrypted using format-preserving encryption.

Abstract: Integrated circuits with sequential access memory cells are provided. A sequential access memory cell may include an inverter-like circuit, an inverter, a preset transistor, an access transistor, and a read circuit. The inverter-like circuit and the inverter are cross-coupled to form a bi-stable latch that is powered by a positive power supply line and that has first and second storage nodes. The preset transistor may be connected between the positive power supply line and the first storage node. The inverter-like circuit may include a transistor in its pull-down path. The preset transistor is enabled while the transistor is disabled to write a “1” at the first storage node. The access transistor may be used to write a “0” into the cell. The read circuit may be connected to the second storage node to read data from the cell without inducing a voltage rise at the second storage node.

Abstract: An electronic device housing may contain a display module. The display module may contain layers of material such as a color filter layer and a thin-film transistor layer. These layers of material may be mounted in a display module chassis. A cover glass may cover the display module. The housing may have springs that mate with corresponding holes in the chassis of the display module to hold the display module in place within the housing. The springs may flex about a flex axis that is perpendicular to a planar rear housing surface and the planar layers of the display module. A disassembly tool may be inserted into a gap between the cover glass and housing sidewalls. When the disassembly tool is rotated, a fin on the tool may press against an engagement structure in the spring and may release the spring from the display module.

Abstract: An electronic device such as a portable music player, cellular telephone, or computer may be provided with an audio jack system that allows audio plug position measurements to be made. Sensors such as optical sensors, magnetic sensors, mechanical sensors, electrical sensors, resistive sensors, and capacitive sensors may be used in monitoring the position and movement of the audio plug relative to the audio jack. A user may rotate the audio plug to control operations such as media playback operations, menu selection operations, and other activities in the electronic device. The audio jack may include flexible structures that allow the audio plug to be tilted relative to the audio jack. Capacitive sensors or other sensors may be used to monitor audio plug tilt and axial audio plug movement. This allows the audio plug to serve as a joystick for the electronic device.

Abstract: Adjustable circuit components may be formed from arrays of differential circuit elements such as differential capacitors and differential current sources. The differential circuit elements may each have a control input. The differential circuit elements in each array of differential circuit elements may be connected in parallel between first and second terminals. A thermometer code control signal may be provided to the control inputs to adjust the capacitance, current, or other parameter associated with the adjustable circuit component. Adjustable circuit components may also be formed from an array of capacitors or other circuit elements having successively increasing strengths.

Abstract: Camera modules are provided using wafer level optics structures. Wafers of optical stack components such as spacers, lenses, filters, and aperture layers may be combined to form optical stacks for camera modules. Each optical stack may be formed from pieces of the lens and spacer wafers. The optical stacks may be mounted above digital image sensors to form compact camera modules for devices such as cellular telephones and digital cameras. To reduce lens flare, a lens hood structure may be mounted above the outermost lens in the optical stack structure. The lens hood structure may be formed from a layer of opaque plastic having an inner surface and an outer surface. The layer of plastic may be provided as part of a camera module housing or as a separate structure. A noncircular lens hood aperture may be formed in the outer surface of the lens hood layer. A corresponding inner aperture may be formed in the inner surface of the lens hood layer adjacent to the optical stack structure.

Abstract: Portable computer structures are provided. The portable computer structures may include hard drive mounting structures. The hard drive mounting structures may include elastomeric support members. Each elastomeric support member may have a relatively rigid inner portion. The inner portion may include a hole that receives a hard drive mounting pin. Each elastomeric support member may also have a relatively flexible outer portion. The relatively flexible outer portion may be mounted within an opening in a plastic support member. The rigid inner portion may have a square outline and may be mounted within a square opening in the flexible outer portion.

Abstract: An adapter may couple an electronic device to a host such as a computer. When coupled in this way, the host may transfer media files to the device. The host may also supply power to the electronic device using power lines in the adapter. The electronic device may have a status indicator such as a light-emitting diode status indicator. The adapter may also have a status indicator. During operation, the electronic device may transmit coded information on the current state of the status indicator in the electronic device by modulating the status indicator or other load in the device at a selected frequency. Control circuitry in the adapter may detect the transmitted state information by monitoring the power lines. The control circuitry may control the status indicator in the adapter so that the status indicator in the adapter replicates the current state of the status indicator in the electronic device.