XXRR7799220033 4400VV,, 33AA SSyynncchhrroonnoouuss SStteepp--DDoowwnn CCOOTT PPoowweerr MMoodduullee April 2016 Rev. 1A GENERAL DESCRIPTION EVALUATION BOARD MANUAL EVALUATION BOARD MANUAL The XR79203 is part of a family of 40V synchronous step-down power modules combining the controller, drivers, inductor, passive components and MOSFETs in a single package for point-of-load supplies. This module requires very few external components leading to ease of design and fast time to market. The XR79203 has load current rating of 3A. A wide 5V to 40V input voltage range allows for single supply operation from industry standard 24V 10%, 18V to 36V and rectified 18VAC and 24VAC rails. With a proprietary emulated current mode Constant On-Time (COT) control scheme, the XR79203 provides extremely fast line and load transient response using ceramic output capacitors. It requires no loop compensation, simplifying circuit implementation and reducing overall component count. The control loop also provides 0.1% load and 0.2% line regulation and maintains constant operating frequency. A FEATURES selectable power saving mode, allows the user to operate in Discontinuous Current Mode 3A step-down power module (DCM) at light current loads significantly o 5V to 40V wide single input increasing the converter efficiency. A host of voltage protection features, including overcurrent, o 0.6V adjustable output voltage over temperature, short-circuit and UVLO, helps achieve safe operation under abnormal Controller, drivers, inductor, passive operating conditions. The XR79203 is available components and MOSFETs integrated in in a RoHS-compliant, green/halogen-free one package space-saving 8mm x 8mm x 4mm QFN Proprietary constant on-time control package. o No loop compensation required o Stable with ceramic output capacitors o Programmable 100ns to 1s on- time o Constant 400kHz to 800kHz frequency o Selectable CCM or DCM/CCM operation Precision enable and power-good flag Programmable soft-start 8mm x 8mm x 4mm QFN package Exar Corporation www.exar.com 48720 Kato Road, Fremont CA 94538, USA Tel. +1 510 668-7000 Fax. +1 510 668-7001 XXRR7799220033 4400VV,, 33AA SSyynncchhrroonnoouuss SStteepp--DDoowwnn CCOOTT PPoowweerr MMoodduullee April 2016 Rev. 1A D1 MMSZ4685-TP C A R1 10k R2 30.1K VIN 2-3=DCM/CCM 3 C13 0.22uF SW 2 1 RLIM 1-2=CCM T3 R3 35.7K J1 CSS 1.8k EN VIN = 24V nominal 47nF Lin VIN+ (short) SS RON VIN 1 2 1 21.5k 2 CBST PGOOD C1 C2 C3 C4 C5 C6 0.1uF 10uF 10uF VIN- RPGOOD 10k 1 VCC 2 U1A T4 AGND 1 41 SS PGND 2 40 PGood PGND FB 3 AGND BST PVin 39 T1 FB PGND 57 62 61 4 500kHz, 3.3V, 3A AGND VOUT+ 5 AGND VOUT 1 6 38 2 VIN VOUT 7 58 37 VCC VOUT 8 SW VOUT 36 C7 C8 C9 C10 C11 C12 PGND VOUT 60 35 VOUT 9 34 47uF 0.1uF VOUT- SW VOUT RR k CR nF 10 33 SW VOUT 11 32 1 SW VOUT 12 31 2 SW VOUT PGND 30 nF VOUT 13 59 29 CAC PGND VOUT T2 XR79203 SW RFB1 CFF 9.09k 220pF VOUT C14 VIN VCC CSNB 0.1uF VCC nF RFF 61 60 0.18k PVin VOUT FB RVIN R5VIN RSNB VIN FB SW 58 59 Ohm SW PGND k 0 CIN CVCC 62 BST3 RFB2 57 0.1uF 4.7uF 2k AGND U2B XR79203 Fig. 1: XR79203 Evaluation Board Schematics PIN CONFIGURATION Fig. 2: XR79203 Pin Assignment Exar Corporation www.exar.com 48720 Kato Road, Fremont CA 94538, USA Tel. +1 510 668-7000 Fax. +1 510 668-7001 14 56 PGND TON 15 55 PGND ENMode 16 PGND 17 54 PGND AGND 18 53 PGND AGND 19 PGND 52 ILIM 51 BST2 20 50 SW BST1 21 SW 22 49 SW PVin 23 48 SW PVin 47 PVin 24 46 VOUT PVin 25 45 VOUT PVin 26 44 VOUT NC 27 VOUT 28 43 VOUT PGND 42 PGND