Maxim MAX840ISA+

Зарядный насос, передатчик сотового телефона2,5 В ~ 10 В-2 В, -0,5 В ~ -9,4 В

Overview

The MAX840/MAX843/MAX844 low-noise, inverting charge-pump power supplies are ideal for biasing GaAsFETs in cellular telephone transmitter amplifiers. They operate with inputs down to 2.5V. The MAX840ISA offers both a -2V preset output and a -0.5V to -9.4V adjustable output. The MAX843/MAX844 use an external positive control voltage to set the negative output voltage. Input voltage range for all the devices is 2.5V to 10V, and output current is 4mA with VIN > 2.7V. These circuits can operate with small capacitors, as low as 0.22μF. An internal linear regulator reduces the MAX840's output voltage ripple to 1mVp-p. With a well-filtered control voltage (VCTRL), the MAX843/MAX844 also achieve less than 1mVp-p typical output ripple. Supply current is 750μA, and reduces to less than 1μA in shutdown (MAX840/MAX843). The MAX844's unregulated output is active in shutdown, with the charge pump switching at 20kHz. It provides a low-power LCD supply.

Features

Applications

• Set-Top Box
• DDR Vooo and Vπ Voltage Generation
• PC Dual Power Supply
• Server DDR Power
• Desktop Computer
• Graphics Cards
• Cell Phones
• Wireless Modems
• PCS Phones
• Two-Way Pagers