5V, -12V, -15V, and Adjustable Inverting Current-Mode PWM Regulators

The MAX736/MAX737/MAX739/!MAX759 are CMOS, in­verting, switch-mode regulators with an internal power MOSFET. Guaranteed output power for the MAX.739 is 1.25W when powered from a +4.5V input, and 1.5W when powered from +6V. Quiescent supply current for the MAX739 is typically 1. 7mA, and a shutdown mode reduces this to 1µ.A. These power-conserving features, along with high efficiency and an application circuit that lends itself to miniaturization, make these parts excel in a broad range of on-card and portable equipment applications.

The MAX736/MAX/737/MAX739 have fixed outputs of -12\/, -15V, and -5V respectively. The MAX759 is adjustable from 0V to -1 SV. Output voltages beyond -15V require a transformer.

These inverting DC-DC converters employ a high-perfor­mance, current-mode, pulse-width modulation (PWM) con­trol scheme to provide tight output voltage regulation and low noise. The fixed-frequency oscillator is factory-trimmed to 165kHz, allowing easy noise filtering. The devices are production tested in an actual application circuit, and output accuracy is guaranteed at ±5% over all specified conditions of line, load, and temperature.

The input voltage range is +4V to + 15V. For similar devices with smaller packages and an input voltage range of +4V to + 11V, refer to the MAX735/MAX755 data sheet.

APPLICATIONS

* Low-Noise Analog Signal Processing Circuits

* LCD Bias Supplies

* Power Supplies for ECL

* Board-Level DC-DC Conversion

* Battery-Powered Equipment

* Computer Peripherals

* Pre-Set -5V, -12V, -15V or Adjustable Outputs

* Convert Positive Voltages to Negative

* 1.25W Guaranteed Output Power

* 83% Typical Efficiency

* 1.7mA Quiescent Current (MAX739)

* 1µA Shutdown Mode (MAX739)

* +4V to +15V Input Voltage Range

* 165kHz Current-Mode PWM - Low Noise and Jitter

* Undervoltage Lockout and Soft-Start Protection