sc480imltrt Semtech Corporation, sc480imltrt Datasheet

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sc480imltrt

Manufacturer Part Number
sc480imltrt
Description
Sc480 Complete Ddr1/2/3 Memory Power Supply
Manufacturer
Semtech Corporation
Datasheet

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Part Number:
SC480IMLTRT
Manufacturer:
SEMTECH
Quantity:
8 000
The SC480 is a combination switching regulator and
linear source/sink regulator intended for DDR1/2/3
memory systems. The purpose of the switching regulator
is to generate the supply voltage, VDDQ, for the memory
system.
time controller designed for high effi ciency, superior DC
accuracy, and fast transient response. The purpose of the
linear source/sink regulator is to generate the memory
termination voltage, VTT, with the ability to source and
sink a 3A peak current.
For the VDDQ regulator, the switching frequency is constant
until a step in load or line voltage occurs at which time the
pulse density, i.e., frequency, will increase or decrease to
counter the transient change in output or input voltage.
After the transient, the frequency will return to steady-state
operation. At lighter loads, the selectable Power-Save
Mode enables the PWM converter to reduce its switching
frequency and improve effi ciency. The integrated gate
drivers feature adaptive shoot-through protection and
soft-switching. Additional features include cycle-by-cycle
current limiting, digital soft-start, over-voltage and under-
voltage protection and a power good fl ag.
For the VTT regulator, the output voltage tracks REF,
which is ½ VDDQ to provide an accurate termination
voltage. The VTT output is generated from a 1.2V to VDDQ
input by a linear source/sink regulator which is designed
for high DC accuracy, fast transient response, and low
external component count. All three outputs (VDDQ, VTT
and REF) are actively discharged when VDDQ is disabled,
reducing external component count and cost. The SC480
is available in a 24-pin MLPQ (4x4 mm) package.
November 3, 2006
POWER MANAGEMENT
Description
Typical Application Circuit
It is a pseudo-fi xed frequency constant on-
VBAT
VTT
VDDQ
REF
R1
1Meg
1nF
C7
C4
10uF
VTTSNS
VDDQ
VDDQ
R6
10R
1uF
C9
C5
10uF
C10
1uF
C1
1uF
5V
1
2
3
4
5
6
PGND2
VTTS
VSSA
TON
REF
VCCA
D1
0.1uF
C8
SC480
U1
1
Features
Applications
PGND1
PGND1
VTT_EN
VDDP
VDDP
R7
PGD
ILIM
PAD
Constant On-Time Controller for Fast Dynamic
Response on VDDQ
DDR1/DDR2/DDR3 Compatible
VDDQ = Fixed 1.8V or 2.5V, or Adjustable from
1.5V to 3.0V
1% Internal Reference (2% System Accuracy)
Resistor Programmable On-Time for VDDQ
VCCA/VDDP Range = 4.5V to 5.5V
VIN Range = 2.5V to 25V
VDDQ DC Current Sense Using Low-Side R
Sensing or External R
FET
Cycle-by-Cycle Current Limit for VDDQ
Digital Soft-Start for VDDQ
Analog Soft-Start for VTT/REF
Smart Over-Voltage VDDQ Protection Against Source-
Current Loads
Combined EN and PSAVE Pin for VDDQ
Over-Voltage/Under-Voltage Fault Protection
Power Good Output
Separate VCCA and VDDP Supplies
VTT/REF Range = 0.75V – 1.5V
VTT Source/Sink 3A Peak
Internal Resistor Divider for VTT/REF
VTT is High Impedance in S3
VDDQ, VTT, REF Are Actively Discharged in S4/S5
24 Lead MLPQ (4x4 mm) Lead-Free Package
Fully WEEE and RoHS Compliant
Notebook Computers
CPU I/O Supplies
Handheld Terminals and PDAs
LCD Monitors
Network Power Supplies
EN/PSV
C2
10R
0.1uF
18
17
16
15
14
13
PAD
Q2
RILIM
R4
C11
1uF
Q1
L1
C6
5V
C3
2x10uF
Memory Power Supply
PGOOD
+
VBAT
Complete DDR1/2/3
VDDQ
SENSE
in Series with Low-Side
www.semtech.com
SC480
DS(ON)

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sc480imltrt Summary of contents

Page 1

POWER MANAGEMENT Description The SC480 is a combination switching regulator and linear source/sink regulator intended for DDR1/2/3 memory systems. The purpose of the switching regulator is to generate the supply voltage, VDDQ, for the memory system pseudo-fi ...

Page 2

POWER MANAGEMENT POWER MANAGEMENT Absolute Maximum Ratings Exceeding the specifi cations below may result in permanent damage to the device or device malfunction. Operation outside of the parameters specifi the Electrical Characteristics section is not implied. Exposure to ...

Page 3

POWER MANAGEMENT Electrical Characteristics (Cont.) TEST CONDITIONS 15V, VCCA = VDDP = VTTEN = EN/PSV = 5V, VDDQ = VTTIN = 1.8V Parameter VDDQ Controller FB Error Comparator Threshold (1) VDDQS Regulation Threshold On-Time Minimum Off-Time ...

Page 4

POWER MANAGEMENT POWER MANAGEMENT Electrical Characteristics (Cont.) TEST CONDITIONS 15V, VCCA = VDDP = VTTEN = EN/PSV = 5V, VDDQ = VTTIN = 1.8V Parameter Under-Voltage Fault Delay Under-Voltage Blank Time Output Over-Voltage Fault Over-Voltage Fault ...

Page 5

POWER MANAGEMENT Electrical Characteristics (Cont.) TEST CONDITIONS 15V, VCCA = VDDP = VTTEN = EN/PSV = 5V, VDDQ = VTTIN = 1.8V Parameter FB Input Thresholds FB Logic Input Low FB Logic Input High Gate Drives ...

Page 6

POWER MANAGEMENT POWER MANAGEMENT Shoot-Through Delay Timing Diagram LX DL tplhDL © 2006 Semtech Corp tplhDH 6 SC480 www.semtech.com ...

Page 7

... NMOS output and requires an external pull-up resistor. 14,15 VDDP +5V supply voltage input for the VDDQ gate drivers. © 2006 Semtech Corp. Ordering Information Device SC480IMLTRT SC480EVB PGND1 Notes Only available in tape and reel packaging. A reel contains 3000 devices. PGND1 2) This product is fully WEEE and RoHS compliant ...

Page 8

POWER MANAGEMENT POWER MANAGEMENT Pin Description (Cont.) Current limit input pin. Connect to drain of low-side MOSFET for RDS(on) sensing or the source 16 ILIM for resistor sensing through a threshold sensing resistor. 17,18 PGND1 Power ground for VDDQ switching ...

Page 9

POWER MANAGEMENT Block Diagram VCCA VDDQS +12% -12% REF DSCHG VCCA VTTRUN EN/ PSV TON TON/ TOFF VDDQS VDDQS DSCHG -10% +16% VMON -30% 1.5V FB -10 +16% © 2006 Semtech Corp. VTTEN OTSD POR/SS DRVH FEDLY DRVL ...

Page 10

POWER MANAGEMENT POWER MANAGEMENT Application Information Application Information +5V Bias Supplies The SC480 requires an external +5V bias supply in addition to the battery. If stand-alone capability is required, the +5V supply can be generated with an external linear regulator. ...

Page 11

POWER MANAGEMENT Application Information Referencing Figure 2, the equation for setting the output voltage is Current Limit Circuit Current limiting of the SC480 can be accomplished in two ways. The on-state ...

Page 12

POWER MANAGEMENT POWER MANAGEMENT Application Information (Cont.) Power Good Output The VDDQ controller has a power good (PGD) output. Power good is an open-drain output and requires a pull- up resistor. When the output voltage is +16%/-10% from its nominal ...

Page 13

POWER MANAGEMENT Application Information (Cont.) Switching Frequency Switching frequency determines the trade-off between size and effi ciency. Higher frequency increases switch- ing losses in the MOSFETs, since losses are a function of F*VIN2. Knowing the maximum input voltage and budget ...

Page 14

POWER MANAGEMENT POWER MANAGEMENT Application Information (Cont.) Dropout Performance The output voltage adjust range for continuous-conduction operation is limited by the fi xed 400nS (typical) Minimum Off-time One-shot. For best dropout performance, use the slowest on-time setting of 200KHz. When ...

Page 15

POWER MANAGEMENT Application Information (Cont.) For stability, place a 10Ω/1μF series combination from REF to VSSA. If REF load capacitance exceeds 1μF, place at least 10Ω in series with the load capacitance to prevent instability possible to use ...

Page 16

POWER MANAGEMENT POWER MANAGEMENT Application Information (Cont.) © 2006 Semtech Corp. where ERR is the transient output tolerance. For this TR case the load transient of 5A (10A - 5A). TRANS For our example: ERR = 144mV and ...

Page 17

POWER MANAGEMENT Application Information (Cont.) R BOT Z V TOP RIPPLE_VBA ( T 0.015 Secondly calculating the value of C this TOP TOP C TOP VBAT Since our example uses internal feedback ,this ...

Page 18

POWER MANAGEMENT POWER MANAGEMENT Application Information (Cont.) Thermal Considerations The junction temperature of the device may be calculated as follows θ J AMB JA where T is the junction temperature temperature the ...

Page 19

POWER MANAGEMENT Application Information (Cont.) accurate signal. The layout can be generally considered in three parts; the control section referenced to VSSA, the VTT output, and the switcher power section. Looking at the control section fi rst, locate all components ...

Page 20

POWER MANAGEMENT POWER MANAGEMENT Application Information (Cont.) VDDQ VTT 10uF 10uF 10uF 0805 0805 0805 R2 1MEG VBAT REF R5 10R 5V C13 C14 1uF 1nF VDDQ © 2006 Semtech Corp 0.1uF 5V MBR0530 C4 ...

Page 21

POWER MANAGEMENT Typical Characteristics 1.8V Effi ciency vs. Output Current Powersave Mode 100% VBAT = 10 90% VBAT = 20 80% 70% 60% 50 (A) OUT 2.5V Effi ciency vs. Output Current Powersave Mode 100% VBAT ...

Page 22

POWER MANAGEMENT POWER MANAGEMENT Typical Characteristics (Cont.) Load Transient Response 5A, Psave Mode Load Transient Response 0A, Psave Mode Load Transient Response 10A © 2006 Semtech Corp. Load Transient Response 5A, Continuous ...

Page 23

POWER MANAGEMENT Typical Characteristics (Cont.) VTT Load Transient Response, 1A Sink/Source, Psave Mode Startup (PSV), EN/PSV Going High © 2006 Semtech Corp. VTT Load Transient Response, 1A Sink/Source, Continuous Conduction Mode Startup (PSV), EN/PSV Going Low, VDDQ = 5A 23 ...

Page 24

POWER MANAGEMENT POWER MANAGEMENT Outline Drawing - MLPQ 24 (4x4mm) PIN 1 INDICATOR (LASER MARK) aaa C NOTES: 1. CONTROLLING DIMENSIONS ARE IN MILLIMETERS (ANGLES IN DEGREES). COPLANARITY APPLIES TO THE EXPOSED PAD AS WELL AS THE TERMINALS. 2. © ...

Page 25

... COMPANY'S MANUFACTURING GUIDELINES ARE MET. Contact Information Phone: (805) 498-2111 Fax: (805) 498-3804 © 2006 Semtech Corp. K DIM Semtech Corporation Power Management Products Division 200 Flynn Road, Camarillo, CA 93012 www.semtech.com 25 SC480 DIMENSIONS INCHES MILLIMETERS (.155) (3.95) 3.10 .122 .106 2.70 .106 2.70 ...

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