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SC488 PDF даташит

Спецификация SC488 изготовлена ​​​​«Semtech Corporation» и имеет функцию, называемую «Complete DDR1/2/3 Memory Power Supply».

Детали детали

Номер произв SC488
Описание Complete DDR1/2/3 Memory Power Supply
Производители Semtech Corporation
логотип Semtech Corporation логотип 

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SC488 Даташит, Описание, Даташиты
POWER MANAGEMENT
Description
The SC488 is a combination switching regulator and lin-
ear source/sink regulator intended for DDR1/2 memory
systems. The purpose of the switching regulator is to gen-
erate the supply voltage, VDDQ, for the memory system.
It is a pseudo-xed frequency constant on-time controller
designed for high efciency, 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 2.8A peak cur-
www.DatarSehneetst4.U.com
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 efciency. 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 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 SC488 is avail-
able in a 24-pin MLPQ (4x4 mm) package.
Typical Application Circuit
SC488
Complete DDR1/2/3
Memory Power Supply
Features
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
1.5% Internal Reference (2.5% System Accuracy)
Resistor Programmable On-Time for VDDQ
VCCA/VDDP Range = 4.5V to 5.5V
VIN Range = 2.5V to 25V
VDDQ DC
Sensing
Current
Sense
Using
Low-Side
RDS(ON)
External RSENSE in Series with Low-Side FET
Cycle-by-Cycle Current Limit for VDDQ
Digital Soft-Start for VDDQ
Analog Soft-Start for VTT/REF
Smart Over-Voltage VDDQ Protection
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 2.8A 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
Product Is Fully WEEE and RoHS Compliant
Applications
Notebook Computers
CPU I/O Supplies
Handheld Terminals and PDAs
LCD Monitors
Network Power Supplies
VTT
VBAT
VDDQ
C4
10uF
C5
10uF
R1
1Meg
VTTSNS
C7
1nF
REF
R6
10R
C9
1uF
5V
C1
1uF
C10
1uF
D1
1 PGND2
2 VTTS
3 VSSA
4 TON
5 REF
6 VCCA
U1
SC488
VDDQ
C8
0.1uF
C2
0.1uF
VBAT
C3
2x10uF
Q1
Q2
PGND1 18
PGND1 17
ILIM 16
VDDP 15
VDDP 14
PGD 13
PAD PAD
RILIM
R4
L1
C6
VDDQ
+
PGOOD
R7 10R
EN/PSV
VTT_EN
5V
C11
1uF
September 28, 2006
1
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SC488 Даташит, Описание, Даташиты
SC488
POWER MANAGEMENT
Absolute Maximum Ratings
Exceeding the specications below may result in permanent damage to the device or device malfunction. Operation outside of the parameters specied in the
Electrical Characteristics section is not implied. Exposure to absolute maximum rated conditions for extended periods of time may affect device reliability.
Parameter
Symbol
Maximum
TON to VSSA
-0.3 to +25.0
DH, BST to PGND1
BST, DH to LX
-0.3 to +31.0
-0.3 to +6.0
LX to PGND1
www.DataSDheLe,tI4LUIM.co, mVDDP to PGND1
VDDP to DL
-2.0 to +25.0
-0.3 to +6.0
-0.3 to +6.0
VTTIN to PGND2; VTT to PGND2; VTTIN to VTT
EN/PSV, FB, PGD, REF, VCCA, VDDQS, VTTEN, VTTS to VSSA
-0.3 to +6.0
-0.3 to +6.0
VCCA to EN/PSV, FB, REF, VDDQS, VTT, VTTEN, VTTIN, VTTS
-0.3 to +6.0
PGND1 to PGND2; PGND1 to VSSA; PGND2 to VSSA
-0.3 to +0.3
Thermal Resistance Junction to Ambient(1)
θJA 29
Operating Junction Temperature Range
TJ -40 to +150
Storage Temperature Range
TSTG
-65 to +150
Peak IR Reow Temperature, 10s - 40s
TPKG
260
ESD Protection Level(2)
VESD
2
Notes:
1) Calculated from package in still air, mounted to 3” x 4.5”, 4 layer FR4 PCB with thermal vias under the exposed pad per JESD51 standards.
2) Tested according to JEDEC standard JESD22-A114-B.
Units
V
V
V
V
V
V
V
V
V
V
°C/W
°C
°C
°C
kV
Electrical Characteristics
Test Conditions: VIN = 15V, VCCA = VDDP = VTTEN = EN/PSV = 5V, VDDQ = VTTIN = 1.8V, RTON = 1MΩ. TAMB = -40 TO +85C.
Parameter
Conditions
25°C
Min Typ Max
Input Supplies
VCCA Operating Current
VCCA Operating Current
VCCA Operating Voltage
VDDP Operating Current
TON Operating Current
VTTIN Operating Current
VCCA + VDDP + TON
Shutdown Current
VTTIN Shutdown Current
S0 State (VTT on); EN/PSV = VCCA;
FB > Regulation Point, IVDDQ = 0A
S3 State (VTT off); EN/PSV = VCCA;
FB > Regulation Point, IVDDQ = 0A
FB > Regulation Point, IVDDQ = 0A
RTON = 1MΩ
IVTT = 0A
EN/PSV = VTTEN = 0V
EN/PSV = VTTEN = 0V
1500
800
5
70
15
1
5
1
-40°C to 85°C
Min Max
Units
2500
μA
1400
μA
4.5 5.5 V
150 μA
μA
5 μA
22 μA
μA
© 2006 Semtech Corp.
2
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SC488 Даташит, Описание, Даташиты
SC488
POWER MANAGEMENT
Electrical Characteristics (Cont.)
Parameter
Conditions
25°C
-40°C to 85°C
Units
Min Typ Max Min Max
VDDQ Controller
FB Error Comparator
Threshold(1)
VDDQS Regulation Threshold
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On-Time
Minimum Off-Time
VDDQS Input Resistance
VDDQS Shutdown
Discharge Resistance
FB Leakage Current
VDDQ Smart
Psave Threshold
VTT Controller
REF Source Current
REF Sink Resistance
REF Output Accuracy
Shutdown Discharge
Resistance (EN/PSV = GND)
VTT Output Accuracy
(with respect to REF)
VTTS Leakage Current
With Adjustable Resistor Divider
FB = AGND
FB = VCCA
RTON = 1MΩ, VDDQ = 1.8V
RTON = 500kΩ, VDDQ = 1.8V
FB < 0.3V
FB > 0.3V
EN/PSV = GND
IREF = 0 to 10mA
VTT
REF
-2A < IVTT < 2A(9)
1.500
2.5
1.8
460
265
400
80
91
16
8
50
900
0.32
8
0
1.4775 1.5225
2.4625
1.773
368
212
2.5375
1.827
552
318
550
V
V
V
ns
ns
kΩ
Ω
-1.0 1.0 μA
%
10 mA
kΩ
882 918 mV
Ω
-40 +40 mV
-1.0 1.0 μA
Current Sensing
ILIM Current
Current Comparator Offset
Zero-Crossing Threshold
DL High
PGND1 - ILIM
PGND1 - LX, EN/PSV = 5V
10 9 11 μA
-10 10 mV
5 mV
VDDQ Fault Protection
Current Limit (Positive)(2)
Current Limit (Negative)
Output Under-Voltage Fault
PGND1 - LX, RLIM = 5kΩ
PGND1 - LX, RLIM = 10kΩ
PGND1 - LX, RLIM = 20kΩ
PGND1 - LX
With Respect to FB Regulation Point
50
100
200
-125
-30
35 65
80 120 mV
170 230
-160 -90 mV
-35 -25 %
© 2006 Semtech Corp.
3
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