sc488mltrt Semtech Corporation, sc488mltrt Datasheet - Page 5

• Manufacturer Part Number: sc488mltrt
• Description: Sc488 Complete Ddr1/2/3 Memory Power Supply
• Manufacturer: Semtech Corporation

Notes:
1) The VDDQ DC regulation level is higher than the FB error comparator threshold by 50% of the ripple voltage.
2) Using a current sense resistor, this measurement relates to PGND1 minus the source of the low-side MOSFET.
3) clks = switching cycles, consisting of one high side and one low side gate pulse.
4) Guaranteed by design.
5) Thermal shutdown latches both outputs (VTT and VDDQ) off, requiring VCCA or EN/PSV cycling to reset.
6) VTT soft-start ramp rate is limited to 5.5mV/μs typical. If the VDDQ/2 ramp rate is slower than 5.5mV/μsec, the VTT soft-start ramp will follow the VDDQ/2
ramp.
7) See Shoot-Through Delay Timing Diagram below.
8) Semtech’s SmartDriver™ FET drive fi rst pulls DH high with a pull-up resistance of 10Ω (typ.) until LX = 1.5V (typ.). At this point, an additional pull-up device
is activated, reducing the resistance to 2Ω (typical). This creates a softer turn-on with minimal power loss, eliminating the need for an external gate or boost
resistor.
9) Provided operation below T
increases with temperature, and by available source voltage (typically VDDQ/2).
POWER MANAGEMENT
Electrical Characteristics (Cont.)
Shoot-Through Delay Timing Diagram
© 2006 Semtech Corp.
Parameter
Gate Drives
Shoot-Thru Protection
Delay
DL Pull-Down Resistance
DL Sink Current
DL Pull-Up Resistance
DL Source Current
DH Pull-Down Resistance
DH Pull-Up Resistance
DH Sink/Source Current
VTT Pull-Up Resistance
VTT Pull-Down Resistance
VTT Peak Sink/Source
Current
(4)(7)
(9)
DL
LX
(8)
J(MAX)
is maintained. VTT output current is also limited by internal MOSFET resistance which is typically 0.32Ω at 25°C and which
tplhDL
DH High, BST - LX = 5V
DH Low, BST - LX = 5V
DH or DL Rising
VTTS < REF
VTTS > REF
Conditions
V
V
V
DL High
DH
DL Low
DL
DL
= 2.5V
= 2.5V
= 2.5V
DH
DL
5
Min
25°C
0.25
0.32
Typ
0.8
3.1
1.3
1.3
2.8
30
2
2
2
tplhDH
Max
-40°C to 85°C
Min
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Max
SC488
Units
ns
Ω
Ω
Ω
Ω
Ω
Ω
A
A
A
A