SC486IMLTRT Semtech, SC486IMLTRT Datasheet
SC486IMLTRT
Specifications of SC486IMLTRT
Available stocks
Related parts for SC486IMLTRT
SC486IMLTRT Summary of contents
Page 1
... VSSA LX 14 VTT 15 VTT VTTIN 13 20 VTTIN VDDP C11 C12 16 PGND2 20uF 1uF 17 18 PGND2 PGND1 1 Complete DDR1/2/3 Memory Power Supply in series with low-side SENSE 5VSUS VBAT R3 470k 10uF 0.1uF 4 R10 C13 Q1 1 1uF www.semtech.com SC486 DS(ON) PGOOD VDDQ + C10 ...
Page 2
... Electrical Characteristics section is not implied. Exposure to Absolute Maximum rated conditions for extended periods of time may affect device reliability Electrical Characteristics Test Conditions 15V, VCCA = VDDP = VTTEN = EN/PSV = 5V, VDDQ = VTTIN = 1.8V, R BAT 2006 Semtech Corp. (10 > > > TON 2 ° ° www.semtech.com SC486 ° ° C ° C ° ° µ A µ µ A µ µ µ A ...
Page 3
... NOT RECOMMENDED FOR NEW DESIGN POWER MANAGEMENT Electrical Characteristics (Cont.) Test Conditions 15V, VCCA = VDDP = VTTEN = EN/PSV = 5V, VDDQ = VTTIN = 1.8V, R BAT 2006 Semtech Corp ° ° ° ° < I < SC486 = 1M TON 2 ° ° ° www.semtech.com µ A µ µ A µ ...
Page 4
... NOT RECOMMENDED FOR NEW DESIGN POWER MANAGEMENT Electrical Characteristics (Cont.) Test Conditions 15V, VCCA = VDDP = VTTEN = EN/PSV = 5V, VDDQ = VTTIN = 1.8V, R BAT 2006 Semtech Corp & SC486 = 1M TON 2 ° ° ° www.semtech.com µ µ µ µ s ° µ ...
Page 5
... VDDQ/2, and then tracks it. (7) See Shoot-Through Delay Timing Diagram below. (8) Semtech’s SmartDriver™ FET drive first pulls DH high with a pull-up resistance of 10 (typ.). At this point, an additional pull-up device is activated, reducing the resistance to 2 need for an external gate or boost resistor. ...
Page 6
... NOT RECOMMENDED FOR NEW DESIGN POWER MANAGEMENT Pin Configuration Top View (MLPQ-24) Pin Descriptions µ 2006 Semtech Corp. Ordering Information S C Note: (1) Only available in tape and reel packaging. A reel contains 3000 devices. (2) Lead-free product. This product is fully WEEE and RoHS compliant ...
Page 7
... NOT RECOMMENDED FOR NEW DESIGN POWER MANAGEMENT Pin Descriptions (Cont Marking Information Top View Part Number yyww = Date Code (Example: 0012) xxxxx = Semtech Lot No. (Example: E9010 xxx 2006 Semtech Corp 1- µ www.semtech.com SC486 ...
Page 8
... NOT RECOMMENDED FOR NEW DESIGN POWER MANAGEMENT Block Diagram 2006 Semtech Corp. Figure 1 - SC486 Block Diagram 8 SC486 www.semtech.com ...
Page 9
... NOT RECOMMENDED FOR NEW DESIGN POWER MANAGEMENT Enable Control Logic Notes: (1) EN/PSV = 1 = EN/PSV high or floating. (2) Discharge resistance = 22 (3) VDDQ is discharged via R4 (see Page 1) so this resistance must be added when calculating discharge times. 2006 Semtech Corp typ www.semtech.com SC486 ...
Page 10
... The high-side switch on-time is determined by a one-shot whose period is directly proportional to output voltage and inversely proportional to input voltage. A second one-shot sets the minimum off-time which is typically 400ns. 2006 Semtech Corp. On-Time One-Shot ( The on-time one-shot comparator has two inputs. One input looks at the output voltage, while the other input samples the input voltage and converts current ...
Page 11
... C6 C7 1uF no-pop VTT VDDQ 2006 Semtech Corp. VDDQ Current Limit Circuit Current limiting of the SC486 can be accomplished in two ways. The on-state resistance of the low-side MOSFETs can be used as the current sensing element or sense resistors in series with the low-side sources can be used if greater accuracy is desired. R sensing is more efficient and less expensive ...
Page 12
... This repeats until either the over-current condition goes away or the part latches off due to output overvoltage (see Output Overvoltage Protection). 2006 Semtech Corp. Power Good Output The VDDQ output has its own power good output. Power good is an open-drain output and requires a pull-up resistor ...
Page 13
... MOSFETs. An adaptive dead-time circuit monitors the DL output and prevents the high-side MOSFET from turning on until DL is fully off (below ~1V). Semtech’s SmartDriver™ FET drive first pulls DH high with a pull-up resistance of 10 (typ.) until LX = 1.5V (typ.). At this ...
Page 14
... For example, if the feedback resistors are chosen to divide down the output by a factor of five, the valley of the output ripple will be 2.5V. If the ripple is 50mV with 2006 Semtech Corp. VBAT = 6V, then the measured DC output will be 2.525V. If the ripple increases to 80mV with VBAT = 25V, then the measured DC output will be 2 ...
Page 15
... SW _ VBAT ( MIN ) V t BAT ( MIN ) ON _ VBAT ( MIN 2006 Semtech Corp. and VBAT ( MAX t is generated by a one-shot comparator that samples ON V via R BAT used to charge an internal 3.3pF capacitor determined by equations above reflect this along with any internal components or delays that influence t ...
Page 16
... For half of full load, divide the I term by 2. For our DDR2 VDDQ example: ERR = 100mV and ERR = 36mV, therefore TR DC 2006 Semtech Corp. R ESR_TR(MAX) We will select a value of 7.5m = 3.28A design, which would be achieved by using two 15m P-P output capacitors in parallel. ...
Page 17
... This calculation assumes the absolute worst case condition of a full-load to no load step transient occurring when the inductor current is at its highest. The capacitance required for smaller transient steps my be 2006 Semtech Corp. calculated by substituting the desired current for the I required to achieve term. ...
Page 18
... FET gate charge, from the FET datasheet ( switching frequency (Hz) VBST = boost pin voltage during duty cycle VTTIN = input voltage for VTT LDO (V) ITT = maximum VTT current (A) 2006 Semtech Corp. Inserting the following values for VBAT this is the worst case condition for power dissipation in the controller example 85° 29° ...
Page 19
... C10 23k2 1u no-pop VTT VDDQ C15 10u Figure 4: DDR2 Reference Design and Layout Example Sample DDR2 Design Using SC486 VBAT = 9V to 19.2V VDDQ = 1.8V @ (8+2)A VTT = 0. 2006 Semtech Corp. VBAT 5VSUS 5VRUN 5VSUS SC486 715k 10R 11 7 VTTEN PGD 3 VDDQS ...
Page 20
... Connect the VSSA pin directly to the thermal pad under the device as the only connection to PGND from VSSA. R4 10R VDDQ C1 R5 4k64 no-pop REF R8 23k2 2006 Semtech Corp 10R R6 C3 10R no-pop C9 C10 C11 ...
Page 21
... C14 quiet layer back to these components. In Figure 8, the VDDQ feedback trace would connect to the red trace. R4 10R 4k64 1u no-pop R8 23k2 VDDQ FEEDBACK Figure 9: VDDQ Feedback and Sense Components and Feedback Trace 2006 Semtech Corp. U1 SC486 11 7 VTTEN PGD 3 VDDQS 1 EN/PSV 2 TON 6 ...
Page 22
... The highest di/dts occur in the input loop (highlighted in red) and thus this should be kept as small as possible. The input capacitors should be placed with the highest frequency capacitors closest to the loop to reduce EMI. Use large copper pours to minimize losses and parasitics. See Figure 11 below for an example. Figure 11: Example VDDQ Power Section Layout 2006 Semtech Corp. VBAT Q1 IRF7811AV 8 ...
Page 23
... Phase nodes (black copper islands (preferred) or wide copper traces. Gate drive traces (red) and phase node traces (blue wide copper traces (L:W < 20:1) and as short as possible, with DL the most critical. Use multiple vias when switching between layers. Locate the current limit resistor (R10) at the chip with a kelvin connection to the phase node. 2006 Semtech Corp. SC486 7 PGD ...
Page 24
... Input capacitor C17 connects directly to the device pins and connects to the ground plane using two vias. Note that PGND1, PGND2 and VSSA all connect to the pad under the device, which should also connect to the ground plane using multiple vias. 2006 Semtech Corp ...
Page 25
... NOT RECOMMENDED FOR NEW DESIGN POWER MANAGEMENT Outline Drawing - MLPQ- 4mm) A PIN 1 INDICATOR (LASER MARK) A aaa NOTES: 1. CONTROLLING DIMENSIONS ARE IN MILLIMETERS (ANGLES IN DEGREES). COPLANARITY APPLIES TO THE EXPOSED PAD AS WELL AS THE TERMINALS. 2. 2006 Semtech Corp DIM E A2 SEATING PLANE C D1 LxN E/2 N bxN bbb D/2 ...
Page 26
... COMPANY'S MANUFACTURING GUIDELINES ARE MET. 2. THERMAL VIAS IN THE LAND PATTERN OF THE EXPOSED PAD SHALL BE CONNECTED TO A SYSTEM GROUND PLANE. FAILURE MAY COMPROMISE THE THERMAL AND/OR FUNCTIONAL PERFORMANCE OF THE DEVICE. Contact Information Phone: (805)498-2111 FAX (805)498-3804 2006 Semtech Corp. K DIM Semtech Corporation Power Management Products Division ...