| FeaturesThe MAX1901/MAX1902/MAX1904 are buck-topology, ♦ 97% Efficiencystep-down, switch-mode, power-supply controllers that♦ 4.2V to 30V Input Rangegenerate logic-supply voltages in battery-powered sys-♦ 2.5V to 5.5V Dual Adjustable Outputstems. These high-performance, dual/triple-output devices♦ Selectable 3.3V and 5V Fixed or Adjustableinclude on-board power-up sequencing, power-good sig-Outputs (Dual Mode™)naling with delay, digital soft-start, secondary winding♦ 12V Linear Regulatorcontrol, low dropout circuitry, internal frequency-compen-♦ Adjustable Secondary Feedbacksation networks, and automatic bootstrapping.(MAX1901/MAX1904)Up to 97% efficiency is achieved through synchronous♦ 5V/50mA Linear Regulator Outputrectification and Maxim’s proprietary Idle Mode™ control♦ Precision 2.5V Reference Outputscheme. Efficiency is greater than 80% over a 1000:1♦ Programmable Power-Up Sequencingload-current range, which extends battery life in system♦ Power-Good (RESET) Outputsuspend or standby mode. Excellent dynamic response♦ Output Overvoltage Protectioncorrects output load transients within five clock cycles.(MAX1901/MAX1902)Strong 1A on-board gate drivers ensure fast external N-♦ Output Undervoltage Shutdownchannel MOSFET switching.(MAX1901/MAX1902)These devices feature a logic-controlled and synchroniz-♦ 333kHz/500kHz Low-Noise, Fixed-Frequencyable, fixed-frequency, pulse-width modulation (PWM)Operationoperating mode. This reduces noise and RF interference♦ Low-Dropout, 98% Duty-Factor Operationin sensitive mobile communications and pen-entry appli-♦ 2.5mW Typical Quiescent Power (12V input, bothcations. Asserting the SKIP pin enables fixed-frequencySMPSs on)mode, for lowest noise under all load conditions.♦ 4µA Typical Shutdown CurrentThe MAX1901/MAX1902/MAX1904 include two PWM reg-ulators, adjustable from 2.5V to 5.5V with fixed 5.0V andOrdering Information3.3V modes. All these devices include secondary feed-back regulation, and the MAX1902 contains a 12V/120mAPART TEMP RANGE PIN-PACKAGElinear regulator. The MAX1901/MAX1904 include a sec-MAX1901EAI -40°C to +85°C 28 SSOPondary feedback input (SECFB), plus a control pinMAX1901ETJ -40°C to +85°C32 Thin QFN 5m m x 5mm (STEER) that selects which PWM (3.3V or 5V) receives thesecondary feedback signal. SECFB provides a methodMAX1902EAI -40°C to +85°C 28 SSOPfor adjusting the secondary winding voltage regulationMAX1902ETJ -40°C to +85°C32 Thin QFN 5m m x 5mm point with an external resistor divider, and is intended toMAX1904EAI -40°C to +85°C 28 SSOPaid in creating auxiliary voltages other than fixed 12V.MAX1904ETJ -40°C to +85°C32 Thin QFN 5m m x 5mm The MAX1901/MAX1902 contain internal output overvolt-age and undervoltage protection |
