rt 7294cgj6f evaluation board ug 7294cgj6f - 00 january 2015 1 http://www.richtek.com rt 7294cgj6f evaluation board purpose the rt7294c is a synchronous step - down converter with advanced constant on - time (acot?) mode control. it can deliver up to 2.5 a output current from a wide input voltage range of 4. 3 v to 18v . this document explains the function and use of the rt7294c evaluation board (evb) and provides information to enable operation and modification of the evaluation board and circuit to suit indi vidual requirements. table of contents purpose ................................ ................................ ................................ ................................ ................................ ................ 1 introduction ................................ ................................ ................................ ................................ ................................ ...... 2 key performance summary table ................................ ................................ ................................ ................................ ... 2 bench test setup con ditions ................................ ................................ ................................ ................................ ............ 3 schematic, bill of m aterials & board lay out ................................ ................................ ................................ ............... 5 more information ................................ ................................ ................................ .......................... e` ! x` important notice for richtek reference de signs ................................ ................................ ..... e` ! x` y o u r p o w e r p a r t n e r .
rt 7294cgj6f evaluation board ug 7294cgj6f - 00 january 2015 2 http://www.richtek.com introduction general product information the rt7294c is a synchronous step - down converter with advanced constant on - time (acot?) mode control. the acot? provides a very fast transient response with few external components. the low impedance internal mosfet supports high efficiency operation with wide input voltage range from 4.3v to 18v. the proprietary ci rcuit of the rt7294c enables to support all ceramic capacitors. the output voltage can be adjusted between 0.6v and 8v. the rt729 4c also provides output under voltage protection and thermal shutdown protection. the low current (< 4 a) shutdown mode provides output disconnection, enabling easy power management in battery - powered systems. the rt7294c is available in tsot - 23 - 6 fcol (fli p - chip - on - lead) package. product feature ? 1.5% high accuracy feedback voltage ? 4.3v to 18v input voltage range ? 2.5a output current ? integrated n - mosfet switches ? acot tm mode control ? fixed frequency operation : 500khz ? output adjustable from 0.6v to 8v ? up to 9 5% efficiency ? fast transient response ? stable with low - esr ceramic output capacitors ? cycle - by - cycle over current protection ? input under voltage lockout ? output under voltage protection ? thermal shutdown protection ? thermal improve fcol package (flip chip on le ad) ? rohs compliant and halogen free key performance summary table key f eatures evaluation b oard n umber: pcb00 7 _v1 default input voltage 12v max output current 2.5 a default output voltage 1.2 v default marking & package type RT7294CGJ6F , tsot - 23 - 6 (fcol) operation frequency steady 50 0khz at all loads other key features acot tm for fast transient response fcol for thermal & efficiency improvement protection output under - voltage protection (hiccup mode): cycle - by - cycle current limit thermal shutdown y o u r p o w e r p a r t n e r .
rt 7294cgj6f evaluation board ug 7294cgj6f - 00 january 2015 3 http://www.richtek.com bench test setup conditions headers description and placement please carefully inspect the evb ic and external components, comparing them to the following bill of materials, to ensure tha t all components are installed and undamaged. if any components are missing or damaged during transportation, please contact the distributor or send e - mail to evb_service@richtek.com test points the evb is provided with the test points and pin names listed in the table below. test point/ pin name signal comment (expected waveforms or voltage levels on test points) vin input voltage input voltage range= 4. 3 v to 18v vout output voltage default output voltage = 1.2 v output voltage range= 0. 6 v to 8 v (see output voltage setting section for changing output voltage level) sw switching nod e test point sw waveform en enable test point enable signal. drive en or instal l a shorting block on jumper jp 2 to enable operation or disable operation. jp 2 chip enable control install jumper or drive en directly to enable or disable operation b oot boot strap supply test point floating supply voltage for the high - side n - mosfet switch gnd ground ground power - up & measurement procedure 1. apply a 12v nominal input power supply (4.3v < v in < 18v) to the vin and gnd terminals. 2. the en voltage is pulled to logic high by r5 (100k to vin) to enable operation. drive en high (>1.5v) to enable operation or low (<0.4v) to disable operation. 3. verify the output voltage (approximately 1.2v) between vout and gnd.6 4. connect an external load up to 2.5a to the vout and gnd terminals and verify the output voltage and current. y o u r p o w e r p a r t n e r .
rt 7294cgj6f evaluation board ug 7294cgj6f - 00 january 2015 4 http://www.richtek.com output voltage setting set the output voltage with the resistive divider (r 2 , r 3 ) between vout and gnd with the midpoint connected to fb. the output is set by the following formula: v out =0.6(1+ r2 r3 ) the installed v out capacitors (c 9 , c 10 ) are 22 f, 16 v x5r ceramic types. do not exceed their operating voltage range and consider their voltage coefficient (capacitance vs. bias voltage) and ensure that the capacitance is sufficient to maintain stability and provide sufficient transient response for your ap plication. this can be verified by checking the output transient response as described in the rt7294c ic datasheet. y o u r p o w e r p a r t n e r .
rt 7294cgj6f evaluation board ug 7294cgj6f - 00 january 2015 5 http://www.richtek.com schematic, bill of materials & board layout evb schematic diagram c3, c4: 10f/50v/x5r, 1206, tdk c3216x5r1h106k c9, c10: 22f/16v/x5r, 1210, murata grm32er61c226k l1: 2h taiyo yuden nr8040t2r0n, dcr=9m y o u r p o w e r p a r t n e r .
rt 7294cgj6f evaluation board ug 7294cgj6f - 00 january 2015 6 http://www.richtek.com bill of materials reference qty part number description package manufacture u1 1 RT7294CGJ6F dc - dc converter tsot - 23 - 6 (fc) richtek c3, c4 2 c3216x5r1h106k160ab 10 f/10%/50v/x5r ceramic capacitor 1206 tdk c9, c10 2 grm32er61c226ke20# 22 f/10%/16v/x5r ceramic capacitor 1210 murata c6, c8, c12 3 c1608x7r1h104k080aa 0.1 f/10%/50v/x7r ceramic capacitor 0603 tdk c1, c11, d2 0 not installed 0603 l1 1 nr8040t2r0n 2.0 h /7.4 a / 3 0% , dcr=9 m , inductor 8mmx8mmx4mm taiyo yuden r2 1 10 k / 1% , resistor 0603 r3 1 10 k / 1% , resistor 0603 r 5 1 100 k / 1% , resistor 0603 cp1 1 short jp2, j5 2 3 - pin header gp 4 en, b( e), boot, sw golden pin tp 3 v out , gnd, vin test pin j3, j6, j7, j8 4 vin, vout, gnd, gnd test pin y o u r p o w e r p a r t n e r .
rt 7294cgj6f evaluation board ug 7294cgj6f - 00 january 2015 7 http://www.richtek.com evb layout top view (1 st layer) bottom view ( 4 th layer) y o u r p o w e r p a r t n e r .
rt 7294cgj6f evaluation board ug 7294cgj6f - 00 january 2015 8 http://www.richtek.com component placement guide component side (1 st la yer) pcb layout component side (1 st layer) y o u r p o w e r p a r t n e r .
rt 7294cgj6f evaluation board ug 7294cgj6f - 00 january 2015 9 http://www.richtek.com pcb layout bottom side ( 4 th layer) y o u r p o w e r p a r t n e r .
rt 7294cgj6f evaluation board ug 7294cgj6f - 00 january 2015 10 http://www.richtek.com more information for more information, please find the related datasheet or application notes from rich t ek website http://www.richtek.com . important notice for richtek evaluation board this document is for reference only, nothing contained in this document shall be construed as richteks warranty, express or implied, under contract, tort or statutory, with respect to the presentation herein. in no event shall richtek be liable to buyer or user for any and all damages including without limitation to direct, indirect, special, punitive or consequential damages. y o u r p o w e r p a r t n e r .
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