Click here for production status of specific part numbers. MAX17557 4.5V to 60V, Synchronous Step-Down Controller General Description Benefits and Features The MAX17557 is a synchronous step-down controller Wide Range of Operation that drives nMOSFETs. The device uses a constant- Wide 4.5V to 60V Input Voltage Range frequency, peak-current-mode architecture. Wide 0.8V to 24V Output Voltage Range R or Inductor DCR Current-Sensing The IC supports current sensing using either an external SENSE 100kHz to 2.2MHz Adjustable Frequency with current-sense resistor for accuracy or an inductor DCR External Clock Synchronization for improved system efficiency. Current foldback limits Available in a Lead (Pb)-Free 20-Pin, 4mm x 4mm MOSFET power dissipation under short-circuit conditions. TQFN-EP Package The IC can start up monotonically into a prebiased output. The device can be operated in forced pulse-width modu- Enhances Power Efficiency Low-Impedance Gate Drives for High Efficiency lation (PWM), or discontinuous-conduction mode (DCM) to enable high efficiency under full-load and light-load DCM Operation at Light Loads Auxiliary Bootstrap LDO conditions. The device features a programmable soft-stop enable (SSTPEN) or disable function. Operates Reliably in Adverse Industrial Environments Programmable Soft-Stop Enable or Disable The IC operates over the -40C to +125C temperature Function range and is available in a lead (Pb)-free, 20-pin TQFN, Adjustable Soft-Start 4mm x 4mm package with an exposed pad. Current Foldback Limits MOSFET Heat Dissipation Applications During a Short-Circuit Condition Overtemperature Protection Industrial Power Supplies High Industrial Ambient Operating Temperature Distributed DC Power Systems Range (-40C to +125C) and Junction Tempera- Motion Control ture Range (-40C to +150C) Programmable Logic Controllers Computerized Numerical Control Ordering Information appears at end of data sheet. 19-100075 Rev 2 5/18MAX17557 4.5V to 60V, Synchronous Step-Down Controller Absolute Maximum Ratings V to PGND .........................................................-0.3V to +65V PGOOD to GND ...........................................-0.3V to V + 0.3V IN IN CSP, CSN to GND .................................................-0.3V to +26V COMP, SS, RT, ILIMSEL, MODE/SYNC .................-0.3V to +6V CSP to CSN .........................................................-0.3V to +0.3V GND to EP ............................................................-0.3V to +0.3V LX, BST to PGND..................................................-0.3V to +65V Continuous Power Dissipation at +70C BST to LX ................................................................-0.3V to +6V (multilayer board) ..................................................2051.30mW BST to V ......................................................-0.3V to +65V Power Deration (multilayer board) ............................25.6mW/C CCINT DH to LX .................................................-0.3V to (V + 0.3)V Operating Temperature Range (Note 1) ........... -40C to +125C BST DL to PGND ........................................-0.3V to (V + 0.3)V Maximum Junction Temperature .....................................+150C CCINT EN, SSTPEN, V to GND ................................-0.3V to +6V Storage Temperature Range ............................ -65C to +160C CCINT V to GND ....................................................-0.3V to +26V Lead Temperature (soldering, 10s) .................................+300C CCEXT PGND to GND ......................................................-0.3V to +0.3V Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings only functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. Note 1: Junction temperature greater than +125C degrades operating lifetimes. Package Information PACKAGE TYPE: 20 TQFN Package Code T2044+3C Outline Number 21-0139 Land Pattern Number 90-0037 THERMAL RESISTANCE, FOUR-LAYER BOARD Junction to Ambient ( ) 39C/W JA Junction to Case ( ) 6C/W JC For the latest package outline information and land patterns (footprints), go to www.maximintegrated.com/packages. Note that a +, , or - in the package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing pertains to the package regardless of RoHS status. Package thermal resistances were obtained using the method described in JEDEC specification JESD51-7, using a four-layer board. For detailed information on package thermal considerations, refer to www.maximintegrated.com/thermal-tutorial. Maxim Integrated 2 www.maximintegrated.com