STMicroelectronics is a French-Italian multinational electronics and semiconductor manufacturer headquartered in Geneva, Switzerland. It is commonly called ST, and it is Europe’s largest semiconductor chip maker based on revenue. While STMicroelectronics corporate headquarters and the headquarters for EMEA region are based in Geneva, the holding company, STMicroelectronics N.V. is registered in Amsterdam, Netherlands.

# LM317T - Three-Terminal Adjustable Regulator

The LM117, LM217, LM317 are monolithic integrated circuits in TO-220, TO-220FP, TO-3 and D²PAK packages intended for use as positive adjustable voltage regulators. They are designed to supply more than 1.5 A of load current with an output voltage adjustable over a 1.2 to 37 V range. The nominal output voltage is selected by means of only a resistive divider, making the device exceptionally easy to use and eliminating the stocking of many fixed regulators.

## Circuit: Adjustable regulator with digitally selected output

A very simple adjustable regulator circuit with digitally selected output is shown above. The circuit is a just a modification of the ordinary voltage regulator using LM317. Parallel to the resistor R4, four more resistor branches each with a transistor switch is added and these resistors can be included or excluded in to the circuit by making the corresponding switching transistor ON. In simple words the output voltage will be according to the logic level of the digital inputs A, B, C and D. Logic high at terminal A will make Q1 ON and so resistor R5 will be added parallel to R4 and so on. Addition of each resistance in parallel to the R4 will reduce the effective resistance of the path and so the output voltage of the resistance will decrease in steps. The width of each step depends on the value of the resistors you choose. Resistor R4 sets the maximum output voltage and it is according to the equation V out Max = 1.25V (1 + (R4/R3)) + (Iadj x R4).

# NE556 - Dual Precision Timer

The NE556, SA556 and SE556 dual monolithic timing circuits are highly stable controllers capable of producing accurate time delays or oscillation. In the time delay mode of operation, the time is precisely controlled by one external resistor and capacitor. For a stable operation as an oscillator, the free running frequency and the duty cycle are both accurately controlled with two external resistors and one capacitor.

# ULQ2004A - High-Voltage, High-Current Darlington Transistor Array

The ULQ2001, ULQ2003 and ULQ2004 are high voltage, high current Darlington arrays each containing seven open collector Darlington pairs with common emitters. Each channel rated at 500 mA and can withstand peak currents of 600 mA. Suppression diodes are included for inductive load driving and the inputs are pinned opposite the outputs to simplify board layout. The versions interface to all common logic families. These versatile devices are useful for driving a wide range of loads including solenoids, relays DC motors, LED displays filament lamps, thermal print-heads and high power buffers. The ULQ2001A/2003A and 2004A are supplied in 16 pin plastic DIP packages with a copper lead-frame to reduce thermal resistance. They are available also in small outline package (SO16) as ULQ2003D1/2004D1. The ULQ2003 is available as Automotive Grade in SO16 package. The commercial part numbers is shown in the order codes. This device is qualified according to the specification AEC-Q100 of the Automotive market, in the temperature range -40 °C to 125 °C and the statistical tests PAT, SYL, SBL are performed.

# L293D - Quadruple Half-H drivers

The L293 and L293D are quadruple high-current half-H drivers. The L293 is designed to provide bidirectional drive currents of up to 1 A at voltages from 4.5 V to 36 V. The L293D is designed to provide bidirectional drive currents of up to 600-mA at voltages from 4.5 V to 36 V. Both devices are designed to drive inductive loads such as relays, solenoids, dc and bipolar stepping motors, as well as other high-current/high-voltage loads in positive-supply applications.
All inputs are TTL compatible. Each output is a complete totem-pole drive circuit, with a Darlington transistor sink and a pseudo-Darlington source. Drivers are enabled in pairs, with drivers 1 and 2 enabled by 1,2EN and drivers 3 and 4 enabled by 3,4EN. When an enable input is high, the associated drivers are enabled and their outputs are active and in phase with their inputs. When the enable input is low, those drivers are disabled and their outputs are off and in the high-impedance state. With the proper data inputs, each pair of drivers forms a full-H (or bridge) reversible drive suitable for solenoid or motor applications.

## Features

• 600mA OUTPUT CURRENT CAPABILITY PER CHANNEL
• 1.2A PEAK OUTPUT CURRENT (non repetitive) PER CHANNEL
• ENABLE FACILITY
• OVERTEMPERATURE PROTECTION
• LOGICAL “0” INPUT VOLTAGE UP TO 1.5 V (HIGH NOISE IMMUNITY)
• INTERNAL CLAMP DIODES

# ULN2064B - 50V - 1.5 A quad Darlington switches

Designed to interface logic to a wide variety of high current, high voltage loads, these devices each contain four NPN Darlington switches delivering up to 1.5 A with a specified minimum breakdown of 50 V and a sustaining voltage of 35 V measured at 100 mA. The ULN2064B, ULN2066B and ULN2068B contain integral suppression diodes for inductive loads have common emitters. The ULN2074B feature isolated Darlington pinouts and is intended for applications such as emitter follower configurations. Inputs of the ULN2064B, ULN2068B and ULN2074B are compatible with popular 5 V logic families and the ULN2066B are compatible with 6 - 15 V CMOS and PMOS. Type ULN2068B includes a pre-driver stage to reduce loading on the control logic.

# L7805CV - Linear Voltage Regulator, 1.5A 5 V

The L7800 series of three-terminal positive regulators is available in TO-220, TO-220FP, TO-220FM, TO-3 and D2PAK packages and several fixed output voltages, making it useful in a wide range of applications. These regulators can provide local on-card regulation, eliminating the distribution problems associated with single point regulation. Each type employs internal current limiting, thermal shut-down and safe area protection, making it essentially indestructible. If adequate heat sinking is provided, they can deliver over 1A output current. Although designed primarily as fixed voltage regulators, these devices can be used with external components to obtain adjustable voltage and currents.

# M48T58-70pc1 - 5.0V, 64 Kbit (8 Kb x8) TIMEKEEPERSRAM

The M48T58/Y TIMEKEEPER® RAM is a 8 Kb x 8 non-volatile static RAM and real-time clock. The monolithic chip is available in two special packages to provide a highly integrated
battery-backed memory and real-time clock solution.
The M48T58/Y is a non-volatile pin and function equivalent to any JEDEC standard 8b Kb x 8 SRAM. It also easily fits into many ROM, EPROM, and EEPROM sockets, providing the non-volatility of PROMs without any requirement for special WRITE timing or limitations on the number of WRITEs that can be performed.
The 28-pin, 600 mil DIP CAPHAT™ houses the M48T58/Y silicon with a quartz crystal and a
long life lithium button cell in a single package.
The 28-pin, 330 mil SOIC provides sockets with gold plated contacts at both ends for direct connection to a separate SNAPHAT® housing containing the battery and crystal. The unique design allows the SNAPHAT battery package to be mounted on top of the SOIC package after the completion of the surface mount process. Insertion of the SNAPHAT housing after reflow prevents potential battery and crystal damage due to the high temperatures required for device surface-mounting. The SNAPHAT housing is keyed to prevent reverse insertion. The SOIC and battery/crystal packages are shipped separately in plastic anti-static tubes or in tape & reel form.

# M41T00CAPPC1 - Serial access real-time clock (RTC)

The M41T00CAP is a low-power serial real-time clock (RTC) with integral battery and crystal in ST’s 24-pin CAPHAT™ package. It includes a crystal controlled, 32.768 kHz oscillator and has a built-in power sense circuit which detects power failures and automatically switches to the backup battery when a power failure occurs.
Eight registers comprise the clock/calendar function and are configured in binary-coded decimal (BCD) format. Addresses and data are transferred serially via an industry standard, two line, 400 kHz, bidirectional IvertAlign;valsuperscript;None
2C interface. The built-in address register is incremented automatically after each WRITE or READ data byte. The internal lithium coin cell contains ample energy to sustain timekeeping operation for 10 years in the absence of system power. The eight clock address locations contain the century, year, month, date, day, hour, minute, and second in 24-hour BCD format. Corrections for the number of days in a month, including leap year, are made automatically (leap year valid up to year 2100).