DS1050 5-Bit, Programmable, Pulse- Width Modulator: 1kHz, 5kHz, 10kHz, and 25kHz www.maxim-ic.com FEATURES PIN ASSIGNMENT Single 5-bit, programmable, pulse-width modulator (PWM) SCL V 1 8 CC Adjustable Duty Cycle: 0% to 100% 2.7V to 5.5V Operation SDA 2 7 A1 Standard Frequency Values: A0 3 6 A2 1kHz, 5kHz, 10kHz, and 25kHz 2-Wire Addressable Interface GND 4 5 PWM Packages: 8-Pin (150-mil) SOIC and 8-Pin 8-Pin 150-mil SOIC (118-mil) SOP o o Operating Temperature: -40 C to +85 C 8-Pin 118-mil SOP PIN DESCRIPTION ORDERING INFORMATION DS1050Z-001 1kHz 8-Pin 150-mil SOIC V - 2.7V to 5.5V Power Supply CC DS1050Z-005 5kHz 8-Pin 150-mil SOIC PWM - PWM Ouput O DS1050Z-010 10kHz 8-Pin 150-mil SOIC A0, A1, A2 - Device Address DS1050Z-025 25kHz 8-Pin 150 mil SOIC SDA - Serial Data I/O SCL - Serial Clock Input DS1050U-001 1kHz 8-Pin 118-mil SOP GND - Ground DS1050U-005 5kHz 8-Pin 118-mil SOP DS1050U-010 10kHz 8-Pin 118-mil SOP DS1050U-025 25kHz 8-Pin 118-mil SOP DESCRIPTION The DS1050 is a programmable, 5-bit, pulse-width modulator featuring a 2-wire addressable controlled interface. The DS1050 operates from power supplies ranging from 2.7V up to 5.5V. The PWM output provides a signal that swings from 0V to V . The DS1050 requires a typical operating current of 50 A CC and a programmable shutdown supply current of 1 A. Four standard PWM output frequencies are offered and include 1kHz, 5kHz, 10kHz, and 25kHz. The 2-wire addressable interface allows operation of multiple devices on a single 2-wire bus and provides compatibility with other Dallas Semiconductor 2-wire devices such as real-time clocks (RTCs), digital thermometers, and digital potentiometers. The device is ideal for low-cost LCD contrast and/or brightness control, power supply voltage adjustment, and battery charging or current adjustment. The DS1050 is offered in standard integrated circuit packaging including the 8-pin (150-mil) SOIC and space-saving 8-pin (118-mil) SOP. 1 of 17 072701DS1050 OPERATION Interface protocol is simplified to an 8-bit control byte and 8-bit data byte. Information can be read or written to the DS1050 including a commanded shutdown operation. Power-Up Configuration The DS1050 powers-up to half-scale (10000B) providing 50% duty-cycle. In this mode, the DS1050 can be used as a standalone oscillator of the frequency specified. Once powered, the PWM output can be changed via the 2-wire addressable serial port. Pin Description V Power supply terminal. The DS1050 will support operation from power supply voltages ranging cc from +2.7 volts to +5.5 volts. GND Ground terminal. PWM Pulse-width modulated output. This output is a square-wave having amplitudes from 0 volts to O V . The duty cycle of this output is governed by a 5-bit control register. Output duty cycles range from CC 0% to 96.88%. An additional command sequence will provide a 100% duty cycle or full-on. SCL Serial clock input. SDA Serial bi-directional data I/O. A0, A1, A2 Device address (chip selects). 2-Wire Addressable Serial Port Control The 2-wire serial port interface supports a bi-directional data transmission protocol with device addressing. A device that sends data on the bus is defined as a transmitter, and a device receiving data as a receiver. The device that controls the message is called a master. The devices that are controlled by the master are slaves. The bus must be controlled by a master device that generates the serial clock (SCL), controls the bus access, and generates the START and STOP conditions. The DS1050 operates as a slave on the 2-wire bus. Connections to the bus are made via the open-drain I/O lines SDA and SCL. The following I/O terminals control the 2-wire serial port: SDA, SCL, A0, A1, and A2. A 2-wire serial port overview and timing diagrams for the 2-wire serial port can be found in Figures 2 and 5, respectively. Timing information for the 2-wire serial port is provided in the AC Electrical Characteristics table for 2-wire serial communications. 2 of 17