Analog Devices

The AD537 is a monolithic V-F converter consisting of an input amplifier, a precision oscillator system, an accurate internal reference generator and a high current output stage. Only a single external RC network is required to set up any full-scale (F.S.) frequency up to 100 kHz and any F.S. input voltage up to ±30 V. Linearity error is as low as ±0.05% for 10 kHz F.S., and operation is guaranteed over an 80 dB dynamic range. The overall temperature coefficient (excluding the effects of external components) is typically ±30 ppm/°C. The AD537 operates from a single supply of 5 V to 36 V and consumes only 1.2 mA quiescent current.A temperature-proportional output, scaled to 1.00 mV/K, enables the circuit to be used as a reliable temperature-to-frequency converter; in combination with the fixed reference output of 1.00 V, offset scales such as 0°C or 0°F can be generated.The low drift (1µV/°C typ) input amplifier allows operation directly from small signals (e.g., thermocouples or strain gages) while offering a high (250 M(Ω) input resistance. Unlike most V-F converters, the AD537 provides a square-wave output, and can drive up to 12 TTL loads, LEDs, very long cables, etc.The excellent temperature characteristics and long-term stability of the AD537 are guaranteed by the primary bandgap reference generator and the low T.C. silicon chromium thin film resistors used throughout.The device is available in either a TO-116 ceramic DIP or a TO-100 metal can; both are hermetically sealed packages.The AD537 is available in three performance/temperature grades; the J and K grades are specified for operation over the 0°C to +70°C range while the AD537S is specified for operation over the extended temperature range, -55°C to +125°C.PRODUCT HIGHLIGHTSThe AD537 is a complete V-F converter requiring only an external RC timing network to set the desired full-scale frequency and a selectable pull-up resistor for the open collector output stage. Any full-scale input voltage range from 100 mV to 10 volts (or greater, depending on +VS) can be accommodated by proper selection of timing resistor. The full-scale frequency is then set by the timing capacitor from the simple relationship, f = V/10RC.The power supply requirements are minimal, only 1.2 mA quiescent current is drawn from a single positive supply from 4.5 volts to 36 volts. In this mode, positive inputs can vary from 0 volts (ground) to (+Vs - 4) volts. Negative inputs can easily be connected for below ground operation.F-V converters with excellent characteristic are also easy to build by connecting the AD537 in a phase-locked loop. Application particulars are shown in Figure 6.The versatile open-collector NPN output stage can sink up to 20 mA with a saturation voltage less than 0.4 volts. The Logic Common terminal can be connected to any level between ground (or -V) and 4 volts below +Vs. This allows easy direct interface to any logic family with either positive or negative logic levels.The AD537 is available in versions compliant with MIL STD-883. Refer to the Analog Devices Military Product Databook or current AD537/883B data sheet for detailed specifications.

The AD5370* contains forty 16-bit DACs in a single 64-lead LFCSP and a 64-lead LQFP. The device provides buffered voltage outputs with a span that is 4× the reference voltage. The gain and offset of each DAC channel can be independently trimmed to remove errors. For even greater flexibility, the device is divided into five groups of eight DACs. Three offset DAC channels allow the output range of blocks to be adjusted. Group 0 can be adjusted by Offset DAC 0, Group 1 can be adjusted by Offset DAC 1, and Group 2 to Group 4 can be adjusted by Offset DAC 2.The AD5370 offers guaranteed operation over a wide supply range, with VSS from −16.5 V to −4.5 V and VDD from +9 V to +16.5 V. The output amplifier headroom requirement is 1.4 V operating with a load current of 1 mA.The AD5370 has a high speed serial interface that is compatible with SPI, QSPI™, MICROWIRE™, and DSP interface standards and can handle clock speeds of up to 50 MHz.The DAC registers are updated on receipt of new data. All the outputs can be updated simultaneously by taking theLDACinput low. Each channel has a programmable gain and an offset adjust register to allow removal of gain and offset errors.Each DAC output is gained and buffered on chip with respect to an external SIGGNDx input. The DAC outputs can also be switched to SIGGNDx via theCLRpin.ApplicationsLevel setting in automatic test equipment (ATE)Variable optical attenuators (VOA)Optical switchesIndustrial control systemsInstrumentation* Protected by U.S. Patent No. 5,969,657; other patents pending.

The AD5372 /AD5373contain 32, 16-bit or 14-bit digital-to-analog converters (DACs) in a single 64-lead LQFP. The devices provide buffered voltage outputs with a nominal span of 4× the reference voltage. The gain and offset of each DAC can be independently trimmed to remove errors. For even greater flexibility, the device is divided into four groups of eight DACs. Two offset DACs allow the output range of the groups to be altered. Group 0 can be adjusted by Offset DAC 0, and Group 1 to Group 3 can be adjusted by Offset DAC 1.The AD5372 / AD5373 offer guaranteed operation over a wide supply range: VSSfrom −16.5 V to −4.5 V and VDDfrom 9 V to 16.5 V. The output amplifier headroom requirement is 1.4 V operating with a load current of 1 mA.The AD5372 / AD5373 have a high-speed serial interface, which is compatible with SPI, QSPI™, MICROWIRE™, and DSP interface standards and can handle clock speeds of up to 50 MHz.The DAC registers are updated on reception of new data. All the outputs can be updated simultaneously by taking theLDACinput low. Each channel has a programmable gain and an offset adjust register.Each DAC output is gained and buffered on-chip with respect to an external SIGGNDx input. The DAC outputs can also be switched to SIGGNDx via theCLRpin.APPLICATIONSLevel setting in automatic test equipment (ATE)Variable optical attenuators (VOA)Optical switchesIndustrial control systemsInstrumentation

The AD538 is a monolithic real-time computational circuit which provides precision analog multiplication, division, and exponentiation. The combination of low input and output offset voltages and excellent linearity results in accurate computation over an unusually wide input dynamic range. Laser wafer trimming makes multiplication and division with errors as low as 0.25% of reading possible, while typical output offsets of 100 microV or less add to the overall off-the-shelf performance level. Real-time analog signal processing is further enhanced by the device's 400 kHz bandwidth.The AD538's overall transfer function is Vo=Vy(Vz/Vx)m. Programming a particular function is via pin strapping. No external components are required for one-quadrant (positive input) multiplication and division. Two-quadrant (bipolar numerator) division is possible with the use of external level shifting and scaling resistors. The desired scale factor for both multiplication and division can be set using the on-chip +2 V or +10 V references, or controlled externally to provide simultaneous multiplication and division. Exponentiation with an M value from 0.2 to 5 can be implemented with the addition of one or two external resistors.Direct log ratio computation is possible by utilizing only the log ratio and output sections of the chip. Access to the multiple summing junctions adds further to the AD538's flexibility. Finally, a wide power-supply range of ±4.5 V to ±18 V allows operation from standard ±5 V, ± 12 V and ± 15 V supplies.The AD538 is available in two accuracy grades (A and B) over the industrial (-25°C to +85°C) temperature range and one grade (S) over the military (-55°C to +125°C) temperature range. The device is packaged in an 18-pin TO-118 hermetic size-brazed ceramic DIP. A-grade chips are also available.APPLICATIONSOne- or two-quadrant multiply/divideLog ratio computationSquaring/square rootingTrigonometric function approximationsLinearization via curve fittingPrecision AGCPower functions

The AD5380 is a complete, single-supply, 40-channel, 14-bit DAC available in a 100-lead LQFP package. All 40 channels have an on-chip output amplifier with rail-to-rail operation. The AD5380 includes a programmable internal 1.25 V/2.5 V, 10 ppm/°C reference, an on-chip channel monitor function that multiplexes the analog outputs to a common MON_OUT pin for external monitoring, and an output amplifier boost mode that allows optimization of the amplifier slew rate. The AD5380 contains a double-buffered parallel interface that features a 20 nsWRpulse width, an SPI-, QSPI-, -MICROWIRE, -DSP compatible serial interface with interface speeds in excess of 30 MHz, and an I2C-compatible interface that supports a 400 kHz data transfer rate.An input register followed by a DAC register provides double buffering, allowing the DAC outputs to be updated independently or simultaneously using theLDACinput.Each channel has a programmable gain and offset adjust register that allows the user to fully calibrate any DAC channel. Power consumption is typically 0.25 mA/channel with boost off.APPLICATIONSVariable optical attenuators (VOA)Level setting (ATE)Optical micro-electro-mechanical systems (MEMS)Control systemsInstrumentation