The MAX4376/MAX4377/MAX4378 single, dual, and quad precision high-side current-sense amplifiers are available in space-saving packages. They feature buffered voltage outputs that eliminate the need for gain-setting resistors and are ideal for today's notebook computers, cell phones, and other systems where current monitoring is critical. These precision devices are offered in three fixed-gain versions of 20, 50, and 100: GAIN SUFFIX 20 T 50 F 100 HFor example, MAX4376TAUK is a single high-side amplifier with a gain of 20.High-side current monitoring is especially useful in battery-powered systems since it does not interfere with the ground path of the battery charger. The input common-mode range of 0 to +28V is independent of the supply voltage and ensures that the current-sense feedback remains viable even when connected to a battery pack in deep discharge.The full-scale current reading can be set by choosing the appropriate voltage gain and external-sense resistor. This capability offers a high level of integration and flexibility, resulting in a simple and compact current-sense solution.The MAX4376/MAX4377/MAX4378 operate over a supply voltage range of +3V to +28V, draw 1mA of supply current per amplifier, and operate over the full automotive temperature range of -40°C to +125°C. These devices have a wide bandwidth of 2MHz, making them suitable for use inside battery-charger control loops. The buffered outputs drive up to 2mA of output current into a ground-referenced load.The MAX4376 is available in a tiny 5-pin SOT23 package. The MAX4377/MAX4378 are available in space-saving 8-pin µMAX® and 14-pin TSSOP packages, respectively.ApplicationsAutomotiveAutomotive Current DetectBattery ChargersCell PhonesCurrent-Limited Power SuppliesFuel Gauges in PCGeneral-System/Board-Level Current MonitoringNotebook ComputersPA Bias ControlPortable/Battery-Powered SystemsPower-Management SystemsSmart Battery Packages

The MAX4376/MAX4377/MAX4378 single, dual, and quad precision high-side current-sense amplifiers are available in space-saving packages. They feature buffered voltage outputs that eliminate the need for gain-setting resistors and are ideal for today's notebook computers, cell phones, and other systems where current monitoring is critical. These precision devices are offered in three fixed-gain versions of 20, 50, and 100: GAIN SUFFIX 20 T 50 F 100 HFor example, MAX4376TAUK is a single high-side amplifier with a gain of 20.High-side current monitoring is especially useful in battery-powered systems since it does not interfere with the ground path of the battery charger. The input common-mode range of 0 to +28V is independent of the supply voltage and ensures that the current-sense feedback remains viable even when connected to a battery pack in deep discharge.The full-scale current reading can be set by choosing the appropriate voltage gain and external-sense resistor. This capability offers a high level of integration and flexibility, resulting in a simple and compact current-sense solution.The MAX4376/MAX4377/MAX4378 operate over a supply voltage range of +3V to +28V, draw 1mA of supply current per amplifier, and operate over the full automotive temperature range of -40°C to +125°C. These devices have a wide bandwidth of 2MHz, making them suitable for use inside battery-charger control loops. The buffered outputs drive up to 2mA of output current into a ground-referenced load.The MAX4376 is available in a tiny 5-pin SOT23 package. The MAX4377/MAX4378 are available in space-saving 8-pin µMAX® and 14-pin TSSOP packages, respectively.ApplicationsAutomotiveAutomotive Current DetectBattery ChargersCell PhonesCurrent-Limited Power SuppliesFuel Gauges in PCGeneral-System/Board-Level Current MonitoringNotebook ComputersPA Bias ControlPortable/Battery-Powered SystemsPower-Management SystemsSmart Battery Packages

The MAX4376/MAX4377/MAX4378 single, dual, and quad precision high-side current-sense amplifiers are available in space-saving packages. They feature buffered voltage outputs that eliminate the need for gain-setting resistors and are ideal for today's notebook computers, cell phones, and other systems where current monitoring is critical. These precision devices are offered in three fixed-gain versions of 20, 50, and 100: GAIN SUFFIX 20 T 50 F 100 HFor example, MAX4376TAUK is a single high-side amplifier with a gain of 20.High-side current monitoring is especially useful in battery-powered systems since it does not interfere with the ground path of the battery charger. The input common-mode range of 0 to +28V is independent of the supply voltage and ensures that the current-sense feedback remains viable even when connected to a battery pack in deep discharge.The full-scale current reading can be set by choosing the appropriate voltage gain and external-sense resistor. This capability offers a high level of integration and flexibility, resulting in a simple and compact current-sense solution.The MAX4376/MAX4377/MAX4378 operate over a supply voltage range of +3V to +28V, draw 1mA of supply current per amplifier, and operate over the full automotive temperature range of -40°C to +125°C. These devices have a wide bandwidth of 2MHz, making them suitable for use inside battery-charger control loops. The buffered outputs drive up to 2mA of output current into a ground-referenced load.The MAX4376 is available in a tiny 5-pin SOT23 package. The MAX4377/MAX4378 are available in space-saving 8-pin µMAX® and 14-pin TSSOP packages, respectively.ApplicationsAutomotiveAutomotive Current DetectBattery ChargersCell PhonesCurrent-Limited Power SuppliesFuel Gauges in PCGeneral-System/Board-Level Current MonitoringNotebook ComputersPA Bias ControlPortable/Battery-Powered SystemsPower-Management SystemsSmart Battery Packages

The MAX4376/MAX4377/MAX4378 single, dual, and quad precision high-side current-sense amplifiers are available in space-saving packages. They feature buffered voltage outputs that eliminate the need for gain-setting resistors and are ideal for today's notebook computers, cell phones, and other systems where current monitoring is critical. These precision devices are offered in three fixed-gain versions of 20, 50, and 100: GAIN SUFFIX 20 T 50 F 100 HFor example, MAX4376TAUK is a single high-side amplifier with a gain of 20.High-side current monitoring is especially useful in battery-powered systems since it does not interfere with the ground path of the battery charger. The input common-mode range of 0 to +28V is independent of the supply voltage and ensures that the current-sense feedback remains viable even when connected to a battery pack in deep discharge.The full-scale current reading can be set by choosing the appropriate voltage gain and external-sense resistor. This capability offers a high level of integration and flexibility, resulting in a simple and compact current-sense solution.The MAX4376/MAX4377/MAX4378 operate over a supply voltage range of +3V to +28V, draw 1mA of supply current per amplifier, and operate over the full automotive temperature range of -40°C to +125°C. These devices have a wide bandwidth of 2MHz, making them suitable for use inside battery-charger control loops. The buffered outputs drive up to 2mA of output current into a ground-referenced load.The MAX4376 is available in a tiny 5-pin SOT23 package. The MAX4377/MAX4378 are available in space-saving 8-pin µMAX® and 14-pin TSSOP packages, respectively.ApplicationsAutomotiveAutomotive Current DetectBattery ChargersCell PhonesCurrent-Limited Power SuppliesFuel Gauges in PCGeneral-System/Board-Level Current MonitoringNotebook ComputersPA Bias ControlPortable/Battery-Powered SystemsPower-Management SystemsSmart Battery Packages

The MAX4376/MAX4377/MAX4378 single, dual, and quad precision high-side current-sense amplifiers are available in space-saving packages. They feature buffered voltage outputs that eliminate the need for gain-setting resistors and are ideal for today's notebook computers, cell phones, and other systems where current monitoring is critical. These precision devices are offered in three fixed-gain versions of 20, 50, and 100: GAIN SUFFIX 20 T 50 F 100 HFor example, MAX4376TAUK is a single high-side amplifier with a gain of 20.High-side current monitoring is especially useful in battery-powered systems since it does not interfere with the ground path of the battery charger. The input common-mode range of 0 to +28V is independent of the supply voltage and ensures that the current-sense feedback remains viable even when connected to a battery pack in deep discharge.The full-scale current reading can be set by choosing the appropriate voltage gain and external-sense resistor. This capability offers a high level of integration and flexibility, resulting in a simple and compact current-sense solution.The MAX4376/MAX4377/MAX4378 operate over a supply voltage range of +3V to +28V, draw 1mA of supply current per amplifier, and operate over the full automotive temperature range of -40°C to +125°C. These devices have a wide bandwidth of 2MHz, making them suitable for use inside battery-charger control loops. The buffered outputs drive up to 2mA of output current into a ground-referenced load.The MAX4376 is available in a tiny 5-pin SOT23 package. The MAX4377/MAX4378 are available in space-saving 8-pin µMAX® and 14-pin TSSOP packages, respectively.ApplicationsAutomotiveAutomotive Current DetectBattery ChargersCell PhonesCurrent-Limited Power SuppliesFuel Gauges in PCGeneral-System/Board-Level Current MonitoringNotebook ComputersPA Bias ControlPortable/Battery-Powered SystemsPower-Management SystemsSmart Battery Packages

The MAX4400–MAX4403 low-cost, general-purpose op amps offer rail-to-rail outputs, draw only 320µA of quiescent current, and operate from a single +2.5V to +5.5V supply. For additional power conservation, the MAX4401 offers a low-power shutdown mode that reduces supply current to 1µA (max) and puts the amplifier's output in a high-impedance state. These devices deliver ±1.4mA of output current and are unity-gain stable with a 1MHz gain-bandwidth product driving capacitive loads up to 400pF. The MAX4400–MAX4403 are specified to +125°C, making them suitable for use in a variety of harsh environments, such as automotive applications.The MAX4400 single amplifier is available in ultra-small 5-pin SC70 and space-saving 5-pin SOT23 packages. The single MAX4401 includes the shutdown feature and is available in a 6-pin SC70. The MAX4402 is a dual amplifier available in 8-pin SOT23, µMAX®, and SO packages. The MAX4403 quad amplifier is packaged in a 14-pin TSSOP or SO.ApplicationsAutomotiveElectronic Ignition ModulesInfrared ReceiversInstruments and TerminalsPortable CommunicationsSensor Signal DetectionSingle-Supply, Zero-Crossing Detectors

The MAX4400–MAX4403 low-cost, general-purpose op amps offer rail-to-rail outputs, draw only 320µA of quiescent current, and operate from a single +2.5V to +5.5V supply. For additional power conservation, the MAX4401 offers a low-power shutdown mode that reduces supply current to 1µA (max) and puts the amplifier's output in a high-impedance state. These devices deliver ±1.4mA of output current and are unity-gain stable with a 1MHz gain-bandwidth product driving capacitive loads up to 400pF. The MAX4400–MAX4403 are specified to +125°C, making them suitable for use in a variety of harsh environments, such as automotive applications.The MAX4400 single amplifier is available in ultra-small 5-pin SC70 and space-saving 5-pin SOT23 packages. The single MAX4401 includes the shutdown feature and is available in a 6-pin SC70. The MAX4402 is a dual amplifier available in 8-pin SOT23, µMAX®, and SO packages. The MAX4403 quad amplifier is packaged in a 14-pin TSSOP or SO.ApplicationsAutomotiveElectronic Ignition ModulesInfrared ReceiversInstruments and TerminalsPortable CommunicationsSensor Signal DetectionSingle-Supply, Zero-Crossing Detectors

The MAX4430/MAX4431 single and MAX4432/MAX4433 dual operational amplifiers feature wide bandwidth, 16-bit settling times in 37ns, and low-noise/low-distortion operation. The MAX4430/MAX4432 are compensated for unity gain stability and have a small signal -3dB bandwidth of 180MHz. The MAX4431/MAX4433 are compensated for closed-loop gains of +2 or greater and have a small-signal -3dB bandwidth of 215MHz.The MAX4430–MAX4433 op amps require only 11mA of supply current per amplifier while achieving 125dB open-loop gain. Voltage noise density is a low 2.8nV/√Hz, and provides 100dB spurious-free dynamic range (SFDR) at 1MHz. These characteristics make these op amps ideal for driving modern high-speed 14- and 16-bit analog-to-digital converters (ADCs).These high-speed op amps feature wide output voltage swings capable of driving ADCs with ≥ 4V input dynamic range and a high current output drive up to 60mA. Using a voltage feedback architecture, the MAX4430–MAX4433 meet the requirements of many applications that previously depended on current feedback amplifiers.The MAX4430/MAX4431 are available in a space-saving 5-pin SOT23 package, and the MAX4432/MAX4433 are available in an 8-pin µMAX® package.ApplicationsNotebook Computers

The MAX4430/MAX4431 single and MAX4432/MAX4433 dual operational amplifiers feature wide bandwidth, 16-bit settling times in 37ns, and low-noise/low-distortion operation. The MAX4430/MAX4432 are compensated for unity gain stability and have a small signal -3dB bandwidth of 180MHz. The MAX4431/MAX4433 are compensated for closed-loop gains of +2 or greater and have a small-signal -3dB bandwidth of 215MHz.The MAX4430–MAX4433 op amps require only 11mA of supply current per amplifier while achieving 125dB open-loop gain. Voltage noise density is a low 2.8nV/√Hz, and provides 100dB spurious-free dynamic range (SFDR) at 1MHz. These characteristics make these op amps ideal for driving modern high-speed 14- and 16-bit analog-to-digital converters (ADCs).These high-speed op amps feature wide output voltage swings capable of driving ADCs with ≥ 4V input dynamic range and a high current output drive up to 60mA. Using a voltage feedback architecture, the MAX4430–MAX4433 meet the requirements of many applications that previously depended on current feedback amplifiers.The MAX4430/MAX4431 are available in a space-saving 5-pin SOT23 package, and the MAX4432/MAX4433 are available in an 8-pin µMAX® package.ApplicationsNotebook Computers

The MAX4430/MAX4431 single and MAX4432/MAX4433 dual operational amplifiers feature wide bandwidth, 16-bit settling times in 37ns, and low-noise/low-distortion operation. The MAX4430/MAX4432 are compensated for unity gain stability and have a small signal -3dB bandwidth of 180MHz. The MAX4431/MAX4433 are compensated for closed-loop gains of +2 or greater and have a small-signal -3dB bandwidth of 215MHz.The MAX4430–MAX4433 op amps require only 11mA of supply current per amplifier while achieving 125dB open-loop gain. Voltage noise density is a low 2.8nV/√Hz, and provides 100dB spurious-free dynamic range (SFDR) at 1MHz. These characteristics make these op amps ideal for driving modern high-speed 14- and 16-bit analog-to-digital converters (ADCs).These high-speed op amps feature wide output voltage swings capable of driving ADCs with ≥ 4V input dynamic range and a high current output drive up to 60mA. Using a voltage feedback architecture, the MAX4430–MAX4433 meet the requirements of many applications that previously depended on current feedback amplifiers.The MAX4430/MAX4431 are available in a space-saving 5-pin SOT23 package, and the MAX4432/MAX4433 are available in an 8-pin µMAX® package.ApplicationsNotebook Computers

The MAX4465–MAX4469 are micropower op amps optimized for use as microphone preamplifiers. They provide the ideal combination of an optimized gain bandwidth product vs. supply current, and low-voltage operation in an ultra-small package. The MAX4465/MAX4467/MAX4469 are unity-gain stable and deliver a 200kHz gain bandwidth from only 24µA of supply current. The MAX4466/MAX4468 are decompensated for a minimum stable gain of +5V/V and provide a 600kHz gain bandwidth product. In addition these amplifiers feature rail-to-rail outputs, high AVOL, plus excellent power-supply rejection and common-mode rejection ratios for operation in noisy environments.The MAX4467/MAX4468 include a complete shutdown mode. In shutdown, the amplifiers' supply current is reduced to 5nA and the bias current to the external microphone is cut off for ultimate power savings. The single MAX4465/MAX4466 are offered in the ultra-small 5-pin SC70 package, while the single with shutdown MAX4467/MAX4468 and dual MAX4469 are available in the space-saving 8-pin SOT23 package.ApplicationsCell PhonesDigital Dictation DevicesHeadsetsHearing AidsMicrophone PreamplifiersPortable ComputingVoice-Recognition Systems

The MAX4534 (single 4-to-1) and MAX4535 (dual 2-to-1) fault-protected multiplexers operate with ±4.5V to±20V dual supplies or a +9V to +36V single supply.These multiplexers feature fault-protected inputs, rail-to-rail signal-handling capability, and overvoltageclamping at 150mV beyond the rails. Both parts feature±40V overvoltage protection with supplies off and ±25Vprotection with supplies on. On-resistance is 400Ω maxand is matched between channels to 10Ω max. All digitalinputs have TTL logic thresholds, ensuringTTL/CMOS-logic compatibility when using a single+12V or dual ±15V supplies.ApplicationsAvionicsData AcquisitionIndustrial and Process ControlRedundant/Backup SystemsSignal Routing

The MAX4564 is a low-voltage, dual-supply, single-pole/double-throw (SPDT) analog switch designed to operate from dual ±1.8V to ±6V or single +1.8V to +12V supplies. The low on-resistance (RON = 40Ω at ±5V) and low power consumption (5µW) make this part ideal for audio, video, and battery-powered applications. This switch offers low leakage currents (1nA max) and fast switching speeds (tON = 60ns and tOFF = 40ns at ±5V, max).The MAX4564 is available in 8-pin SOT23 and µMAX® packages.ApplicationsAudio and Video SwitchingBattery-Operated SystemsCommunication SystemsCommunications CircuitsSample-and-Hold CircuitsTest Equipment

The MAX4591/MAX4592/MAX4593 are high-speed, precision, quad, single-pole/single-throw (SPST) analog switches designed to operate at +12V or +15V. The MAX4591 has four normally closed (NC) switches, and the MAX4592 has four normally open (NO) switches. The MAX4593 has two NO and two NC switches. All three devices offer low leakage (100pA max) and fast switching speeds (tON 80ns, tOFF 45ns).With a +12V supply, the MAX4591/MAX4592/MAX4593 offer guaranteed 1Ω max channel-to-channel matching, 20Ωs max on-resistance (RON), and 1.75Ω max RON flatness over the specified range.These switches are also fully specified for single +15V operation, with 16Ωs max RON, 1.5Ω max RON match, and 1.5Ω max flatness. For low-voltage or dual-supply operation, refer to the MAX391 data sheet.These low-voltage switches also offer 5pC max charge injection, and electrostatic discharge (ESD) protection is greater than 2000V, per Method 3015.7.ApplicationsCell PhonesComputers: Desktop, Workstation, ServerConsumer AudioDigital Television (Receivers, Set-Top Boxes)Network Hubs, Switches, Routers

The MAX4614/MAX4615/MAX4616 quad, low-voltage, high-speed, single-pole/single-throw (SPST) analog switches are pin compatible with the industry-standard 74HC4066/MAX4610 analog switches. On-resistance (10Ω max) is matched between switches to 1Ω max and is flat (1Ω max) over the specified signal range. Each switch handles V+ to GND analog signal levels. Maximum off-leakage current is only 1nA at TA = +25°C and 6nA at TA = +85°C.The MAX4614 has four normally open (NO) switches, and the MAX4615 has four normally closed (NC) switches. The MAX4616 has two NO switches and two NC switches. These CMOS switches operate from a single +2V to +5.5V supply. All digital inputs have +0.8V and +2.4V logic thresholds, ensuring TTL/CMOS-logic compatibility when using a single +5V supply.ApplicationsAudio/Video Signal RoutingBattery-Powered ApplicationsCommunication SystemsLow-Voltage Data AcquisitionSample-and-Hold Circuits

The MAX4621/MAX4622/MAX4623 are precision, dual, high-speed analog switches. The single-pole/single-throw (SPST) MAX4621 and double-pole/single-throw (DPST) MAX4623 dual switches are normally open (NO). The single-pole/double-throw (SPDT) MAX4622 has two normally closed (NC) and two NO poles. All three parts offer low 5Ω on-resistance guaranteed to match to within 0.5Ω between channels and to remain flat over the full analog signal range (Δ0.5Ω max). They also offer low leakage (These analog switches are ideal in low-distortion applications and are the preferred solution over mechanical relays in automatic test equipment or applications where current switching is required. They have low power requirements, use less board space, and are more reliable than mechanical relays.The MAX4621/MAX4622/MAX4623 are pin-compatible replacements for the DG401/DG403/DG405, respectively, offering improved overall performance. These monolithic switches operate from a single positive supply (+4.5V to +36V) or with bipolar supplies (±4.5V to ±18V) while retaining CMOS-logic input compatibility.ApplicationsAudio-Signal RoutingAvionicsCommunication SystemsData AcquisitionMilitary RadiosPBX/PABX SystemsReed Relay ReplacementTest Equipment

The MAX526/MAX527 contain four 12-bit, voltage-output digital-to-analog converters (DACs). Precision output buffer amplifiers are included on-chip to provide voltage outputs. The MAX527 operates with ±5V power supplies, while the MAX526 utilizes -5V and +12V to +15V supplies. Offset, gain, and linearity are factory calibrated to provide the MAX526’s 1LSB total unadjusted error (TUE). These devices feature double-buffered interface logic with a 12-bit input register and a 12-bit DAC register. Data in the DAC register sets the DAC output voltage. The MAX526/MAX527 have an 8-bit-wide data bus. Data is loaded into the input register using the two write operations with an 8-bit LSB write load and a 4-bit MSB write load. An asynchronous load DAC (active-low LDAC) input transfers data from the input register to the DAC register. All logic inputs are TTL and CMOS compatible.The MAX526/MAX527 are available in 24-pin, 300 mil plastic DIP, Ceramic SB, and wide SO packages.ApplicationsArbitrary Function GeneratorsAutomatic Test EquipmentDigital Offset and Gain AdjustmentIndustrial Process ControlsMinimum Component Count Analog Systems

The MAX5427/MAX5428/MAX5429 linear-taper digitalpotentiometers function as mechanical potentiometers,but replace the mechanics with a simple 2-wire digitalinterface. These digital potentiometers are unique in thatthey have an optional one-time programmable featurethat either sets the wiper's power-on reset (POR) positionto a user-defined value, or the wiper can be set andthe interface disabled to prevent further adjustment.The MAX5427 has an end-to-end resistance of 100kΩ,the MAX5428 a resistance of 50kΩ, and the MAX5429 aresistance of 10kΩ. All these devices have 32 wiperpositions, operate from a single 2.7V to 5.5V supply, anduse less than 1.5µA (max) static supply current.The MAX5427/MAX5428/MAX5429 are available in8-pin thin QFN and µMAX® packages. Each device isguaranteed over the extended temperature range of-40°C to +85°C.ApplicationsMechanical Potentiometer ReplacementsProducts Using One-Time Factory Calibration

The MAX5821 is a dual, 10-bit voltage-output, digital-to-analog converter (DAC) with an I²C-compatible, 2-wire interface that operates at clock rates up to 400kHz. The device operates from a single 2.7V to 5.5V supply 115µA at VDD = 3.6V. A power-down mode decreases current consumption to less than 1µA. The MAX5821 features three software-selectable power-down output impedances: 100kΩ, 1kΩ, and high impedance. Other features include internal precision Rail-to-Rail output buffers and a power-on reset (POR) circuit that powers up the DAC in the 100kΩ power-down mode.The MAX5821 features a double-buffered I²C-compatible serial interface that allows multiple devices to share a single bus. All logic inputs are CMOS-logic compatible and buffered with Schmitt triggers, allowing direct interfacing to optocoupled and transformer-isolated interfaces. The MAX5821 minimizes digital noise feedthrough by disconnecting the clock (SCL) signal from the rest of the device when an address mismatch is detected. The MAX5821 is specified over the extended temperature range of -40°C to +85°C and is available in a miniature 8-pin µMAX® package. Refer to the MAX5822 data sheet for the 12-bit version.ApplicationsBattery-Powered ApplicationsDigital Gain and Offset ControlLow-Cost InstrumentationProgrammable AttenuatorsProgrammable Voltage and Current SourcesVCO/Varactor Diode Control

The MAX5841 is a quad, 10-bit voltage output, digital-to-analog converter (DAC) with an I²C*-compatible, 2-wire interface that operates at clock rates up to 400kHz. The device operates from a single 2.7V to 5.5V supply and draws only 230µA at VDD = 3.6V. A power-down mode decreases current consumption to less than 1µA. The MAX5841 features three software-selectable power-down output impedances: 100kΩ , 1kΩ , and high impedance. Other features include internal precision Rail-to-Rail output buffers and a power-on reset (POR) circuit that powers up the DAC in the 100kΩ power-down mode.The MAX5841 features a double-buffered I²C-compatible serial interface that allows multiple devices to share a single bus. All logic inputs are CMOS-logic compatible and buffered with Schmitt triggers, allowing direct interfacing to optocoupled and transformer-isolated interfaces. The MAX5841 minimizes digital noise feedthrough by disconnecting the clock (SCL) signal from the rest of the device when an address mismatch is detected.The MAX5841 is specified over the extended temperature range of -40°C to +85°C and is available in a miniature 10-pin µMAX® package. Refer to the MAX5842 data sheet for the 12-bit version.ApplicationsAutomated Test Equipment (ATE)Battery-Powered ApplicationsDigital Gain and Offset ControlLow-Cost InstrumentationProgrammable AttenuatorsProgrammable Voltage and Current SourcesVCO/Varactor Diode Control