MAXIM Manuals

The MAX690A/MAX692A/MAX802L/MAX802M/MAX805L are microprocessor supervisory circuits that reduce complexity and reduce the number of components required for power supply monitoring and battery control functions in µP systems. They significantly improve system reliability and accuracy compared to separate ICs or discrete components.

MAX6846–MAX6849 is an ultra-low power battery monitor with integrated microprocessor (µP) supervisors. The user-adjustable battery monitors are offered with single or dual low-battery output options that can be used to signal when the battery is OK (enabling full system operation), when the battery is low (for low- power system operation), and when the battery is dead (to disable system operation).

The MAX6427-MAX6438 are single/dual-level battery monitors with internal hysteresis. These devices are offered with single (MAX6427/MAX6428/MAX6429, MAX6433/ MAX6434/MAX6435) or dual (MAX6430/MAX6431/ MAX6432, MAX6436/MAX6437/MAX6438) low-battery output indicators, which can be used to indicate three battery conditions: battery is good (operate system in normal mode), battery is weak (operate system in low-power mode), or battery is empty (disable the system). These devices are ideal for monitoring single lithium-ion (Li+) cells or multicell alkaline/NiCd/NiMH power supplies. When the power-supply voltage drops below the specified low threshold, the low-battery output asserts. When the voltage rises above the specified high threshold, the low- battery output is deasserted following a 140ms minimum timeout period. The timeout period ensures that the supply voltages have stabilized before power-converter or micro- processor activity is enabled. The MAX6427–MAX6438 family is available with several monitoring options. The MAX6427/MAX6428/MAX6429 offer factory-trimmed battery-monitor thresholds, with a single low-battery output. The MAX6430/MAX6431/MAX6432 also feature factory-trimmed thresholds, but have two low- battery outputs. The MAX6433–MAX6438 have user-adjustable threshold voltages permitting the user to select the hysteresis range, and consequently the sensitivity of the system to noise. A wide hysteresis range also prevents chattering that can result in frequent power-converter or micro-controller switching.

The MAX6361/MAX6363/MAX6364 supervisory circuits reduce the complexity and number of components required for power-supply monitoring and battery control functions in microprocessor (µP) systems. The circuits significantly improve system reliability and accuracy compared to that obtainable with separate ICs or discrete components. Their functions include µP reset, backup-battery switchover, and power failure warning. The MAX6361/MAX6363/MAX6364 operate from supply voltages as low as +1.2V. The factory preset reset threshold voltage ranges from 2.32V to 4.63V (see Ordering Information). These devices provide a manual reset input (MAX6361), battery-on output (MAX6363), and an auxiliary adjustable reset input (MAX6364). In addition, each part type is offered in three reset output versions: an active-low push-pull reset, an active-low open-drain reset, and an active-high push-pull reset (see Selector Guide at end of data sheet).

The MAX4178/MAX4278 are ±5V, wide-bandwidth, fast-settling, closed-loop buffers featuring high slew rate, high precision, high output current, low noise, and low differential gain and phase errors. The MAX4178, with a -3dB bandwidth of 330MHz, is preset for unity voltage gain (0dB). The MAX4278 is preset for a voltage gain of +2 (6dB) and has a 310MHz -3dB bandwidth. The MAX4178/MAX4278 feature the high slew rate and low power that are characteristic of current-mode feedback amplifiers. However, unlike conventional current-mode feedback amplifiers, these devices have a unique input stage that combines the benefits of cur- rent-feedback topology with those of the traditional volt- age-feedback topology. This combination results in low input offset voltage and bias current, low noise, and high gain precision and power-supply rejection. The MAX4178/MAX4278 are ideally suited for driving 50Ω or 75Ω loads. They are the perfect choice for high-speed cable-driving applications, such as video routing. The MAX4178/MAX4278 are available in DIP, SO, and space-saving µMAX and SOT23 packages.

The MAX187/MAX189 are 12-bit serial analog-to-digital converters (ADCs) from Texas Instruments with 8.5µs sampling rate and 75ksps throughput rate. They support SPI™, QSPI™ and Microwire™ interface.

MAX1744/MAX1745 are high-voltage, step-down DC-DC controllers in µMAX capable of handling up to 36V inputs. These parts use a proprietary current-limited control scheme for excellent light- and full-load efficiency, while their 330kHz (max) switching frequency permits small external components for space-critical applications. Operation to 100% duty cycle permits the lowest possible dropout voltage. The MAX1744 contains an internal feedback network that provides a pin-selectable output voltage of either 3.3V or 5V. The MAX1745 uses an external feedback network to generate an adjustable output voltage between 1.25V and 18V. The MAX1744/MAX1745 are available in a space-saving 10-pin µMAX package.

The MAX1583 evaluation kit (EV kit) is a fully assembled and tested surface-mount circuit board for evaluating the MAX1583 white LED flash boost converter. The EV kit accepts a 2.6V to 5.5V input voltage and drives up to five series white LEDs with a constant current to pro- vide camera flash/strobe in cell phones, PDAs, DSCs, and other hand-held devices. The MAX1583 switching frequency is 1MHz, allowing tiny external components. Two logic inputs control four modes of operation: shut- down mode (0.5µA max), movie mode for high-efficien- cy continuous lighting (programmable up to 100mA), precharge mode for charging a reservoir capacitor to 24V while the LEDs are off (POK output indicates a full reservoir capacitor), and strobe mode for firing the flash during an exposure with a regulated current program- mable up to 300mA (100mA with installed compo- nents). A pushbutton pulse generator is installed to sim- ulate a 30ms flash pulse. The MAX1583 comes with the MAX1583X (1A current limit) installed, but the entire MAX1583 family can be eval- uated with this EV kit with minor component changes.

The MAX1242/MAX1243 are low-power, 10-bit analog-to-digital converters (ADCs) available in 8-pin pack- ages. They operate with a single +2.7V to +5.25V supply and feature a 7.5µs successive-approximation ADC, a fast track/hold (1.5µs), an on-chip clock, and a high-speed, 3-wire serial interface. Power consumption is only 3mW (VDD = 3V) at the 73ksps maximum sampling speed. A 2µA shutdown mode reduces power at slower throughput rates. The MAX1242 has an internal 2.5V reference, while the MAX1243 requires an external reference. The MAX1243 accepts signals from 0V to VREF, and the reference input range includes the positive supply rail. An exter- nal clock accesses data from the 3-wire interface, which connects directly to standard microcontroller I/O ports. The interface is compatible with SPI™, QSPI™, and Microwire™. Excellent AC characteristics and very low power com- bined with ease of use and small package size make these converters ideal for remote-sensor and data- acquisition applications, or for other circuits with demanding power consumption and space require- ments. The MAX1242/MAX1243 are available in 8-pin DIP and SO packages. Applications Portable Data Logging Process Control Monitoring Test Equipment Temperature Measurement Isolated Data Acquisition

The MAX1065/MAX1066 are 14-bit, low-power successive approximation analog-to-digital converters (ADCs) that feature automatic power-down, a factory-trimmed internal clock, and a high-speed, 14-bit-wide (MAX1065) or byte-wide (MAX1066) parallel interface. The devices operate from a single 4.75V to 5.25V analog supply and a 2.7V to 5.25V digital supply. The MAX1065/MAX1066 use an internal 4.096V reference or an external reference. The MAX1065/MAX1066 consume only 1.8mA at a sampling rate of 165ksps with external reference and 2.7mA with internal reference. AutoShutdown™ reduces supply current to 0.1mA at 10ksps. The MAX1065/MAX1066 are ideal for high-performance, battery-powered, data-acquisition applications. Excellent dynamic performance and low-power consumption in a small package make the MAX1065/ MAX1066 the best choice for circuits with demanding power consumption and space requirements. The 14-bit-wide MAX1065 is available in a 28-pin TSSOP package, and the byte-wide MAX1066 is available in a 20-pin TSSOP package. Both devices are available in either the 0°C to +70°C commercial, or the -40°C to +85°C extended temperature range.

The MAX6315 is a low-power CMOS microprocessor (µP) supervisory circuit designed specifically for monitoring power supplies in µPs and digital systems. It provides excellent circuit reliability and low cost by eliminating external components and adjustments.