SC1480EVB SEMTECH [Semtech Corporation], SC1480EVB Datasheet
SC1480EVB
Related parts for SC1480EVB
SC1480EVB Summary of contents
Page 1
POWER MANAGEMENT Description The SC1480 is a single output, constant on-time synchronous-buck, pseudo-fixed frequency, PWM controller intended for use in notebook computers and other battery operated portable devices. Features include high efficiency and fast dynamic response with no minimum on ...
Page 2
POWER MANAGEMENT Absolute Maximum Ratings Exceeding the specifications below may result in permanent damage to the device, or device malfunction. Operation outside of the parameters specified in the Electrical Characteristics section is not implied ...
Page 3
POWER MANAGEMENT Electrical Characteristics Cont. Test Conditions 2.5V, REFIN = 1.25, VCCA = VDDP = 5.0V ...
Page 4
POWER MANAGEMENT Electrical Characteristics Cont. Test Conditions 2.5V, REFIN = 1.25, VCCA = VDDP = 5.0V ...
Page 5
POWER MANAGEMENT Pin Configuration TOP VIEW REFIN 1 TON 2 REFOUT 3 VCCA 4 FBK 5 PGOOD 6 AGND 7 (14 Pin TSSOP) Pin Descriptions ...
Page 6
POWER MANAGEMENT Block Diagram VDDQ = 2.5V VDDQ 1 REFIN 2 VIN REFOUT 3 +5V REFOUT 4 VCCA VOUT FBK 6 PGOOD 7 AGND 2006 Semtech Corp. VCCA VDDP POR/ CONTROL TON OFF LOGIC PWM ...
Page 7
POWER MANAGEMENT Applications Information +5V Bias Supply The SC1480 requires an external +5V bias supply in ad- dition to the battery. If stand-alone capability is required, the +5V supply can be generated with an external linear regulator. There are two ...
Page 8
POWER MANAGEMENT Applications Information (Cont.) a scaling resistor between LX and ILIM is required. This resistor connected ILIM within the SC1480 through the ILIM pin. This sets a volt- age drop equal to 10 ...
Page 9
POWER MANAGEMENT Applications Information (Cont.) Power Good Output Power good is an open-drain output and requires a pull- up resistor. When the output voltage is 10% above or below its set voltage, PGOOD gets pulled low held low ...
Page 10
POWER MANAGEMENT Applications Information (Cont.) The selection of the ripple current is based on the maxi- mum output current and tends to be between 20% to 50% of the maximum load current. Again, cost, size and efficiency all play a ...
Page 11
POWER MANAGEMENT Applications Information (Cont.) Where V is the final output voltage after release of the F load and V is the initial voltage prior to the release of I load more than 100mV of output voltage variation ...
Page 12
POWER MANAGEMENT Applications Information (Cont 150 1. θ JA Each FET must not exceed 1.3W of power dissipation. MOSFET Power Dissipation Worst-case conduction losses occur at the duty factor extremes. For the ...
Page 13
POWER MANAGEMENT Applications Information (Cont.) The error comparator offset is trimmed so that it trips when VOUT is 1.25 volts +/-1% at room temperature. This offset does not drift significantly with supply and temperature. Thus, the error comparator contributes 1% ...
Page 14
POWER MANAGEMENT Reference Design 4.5V - 25V 2.50V_SUS R1 20K REFOUT C3 +5V_SUS R2 1uF 1M R3 20K + PGOOD R7 NO_POP C6 C7 1uF 1000pF VIN = 4.5V - 25V VOUT = 1.25V; IOUT = ...
Page 15
POWER MANAGEMENT Reference Design - Bill of Material ...
Page 16
POWER MANAGEMENT Evaluation Board Schematic TP1 +5V C1 TP2 10uF/6.3V J1 5VRUN GND TP3 5VRUN C2 TP4 10uF/6.3V GND VIN R5 1M TP7 C7 +5V REFO 1uF C9 TP8 1uF R6 1M RGND TP9 PGD R8 NO_POP ...
Page 17
POWER MANAGEMENT Evaluation Board - Bill of Materials ...
Page 18
POWER MANAGEMENT Gerber Plots Silk Screen Layer Power Ground Layer Top Layer 2006 Semtech Corp. Bottom Layer Analog Ground Layer 18 SC1480 www.semtech.com ...
Page 19
... Frequency vs. Load Current (V = 15V 1.25V, Rton = 1M) IN OUT 290 280 270 260 250 240 230 220 210 200 Load Current (Amps) 2006 Semtech Corp. = 1.25V SC1480EVB Line Regulation at V OUT 0.6 0.5 0.4 0.3 0.2 VIN=25V VIN=14V VIN=4.5V 0.1 0 3.5 4 4.5 5 4.5 = 1.25V OUT 280 270 260 250 ...
Page 20
POWER MANAGEMENT Typical Characteristic (Cont.) Upper Trace: Phase Lower Trace: Output Ripple Voltage Upper Trace -2A Load Transient Lower Trace: Output Ripple Voltage 2006 Semtech Corp. Upper Trace +2A Transient Lower Trace: Output Ripple Voltage Upper ...
Page 21
POWER MANAGEMENT Marking Diagram Top Mark yy = two-digit year of manufacture ww = two-digit week of manufacture 2006 Semtech Corp. Bottom Mark xxxxxx = Wafer Lot Number xx = Assembly Lot Number 21 SC1480 www.semtech.com ...
Page 22
POWER MANAGEMENT Outline Drawing - TSSOP-14 2X E/2 PIN 1 INDICATOR ccc C 2X N/2 TIPS aaa C SEATING PLANE C NOTES: 1. CONTROLLING DIMENSIONS ARE IN MILLIMETERS (ANGLES IN DEGREES). 2. DATUMS 3. DIMENSIONS "E1" AND "D" DO NOT ...