lx1676 Microsemi Corporation, lx1676 Datasheet

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lx1676

Manufacturer Part Number
lx1676
Description
Mobile Amd Athlontm Vrm Controller
Manufacturer
Microsemi Corporation
Datasheet
Copyright © 2000
Revision: 1.0, 4/12/2005
VRM power supply controller IC
featuring
regulator stages.
voltage-mode
configured as a single biphase high
current output core supply.
current (>25A) output is generated by
a LoadSHARE
balances the currents in the two
phases. Power loss and noise, due to
the ESR of the input capacitors, are
minimized by operating the PWMs
180° out of phase.
Correction Loop† provides except-
ional control of the output droop and
overshoot during very high di/dt load
changes, the circuit can be configured
for droop only, overshoot only or
both.
capacitor
IMPORTANT: For the most current data, consult MICROSEMI’s website:
† Patent numbers US6292378,US6285571,US6356063, US6605931
The LX1676 is a highly integrated
The
In biphase operation, the high
This architecture also minimizes
A
TM
two
synchronized
Note: Available in Tape & Reel. Append the letters “TR” to the part number. (i.e. LX1676CLQ-TR)
two
5 B i t V I D
T
0 to 70
requirements
J
7 0 n H
PWM
TM
constant
(°C)
† technique that
PWM
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
V i n + 5 V
phases
PW
RoHS Compliant / Pb-free Transition DC: 0518
frequency
switching
Transient
D E S C R I P T I O N
while
Plastic TSSOP
38-Pin
are
T r a n s i e n t C o r r e c t i o n L o o p
L X 1 6 7 6
maximizing regulator response.
used for remote voltage sensing at the
processor core.
internal reference that will set the
output voltage. This VID code can be
changed during operation and the
reference will slew the output voltage to
its new setting at a preset rate. During
VID changes on the fly the Power Good
indication will stay valid.
MOSFET will be sampled using its
R
down.
voltage circuit will trip at a specified
setting and clamp the output by turning
off the upper MOSFETs and turning on
the lower MOSFETs.
a bootstrap capacitor to provide the
upper drive voltage over the input
voltage range of 6 to 24 volts.
LX1676CPW
DS(ON)
A true differential input amplifier is
A VID code generator provides an
Current through the lower phase 1
For further protection, an over
The upper MOSFET drivers will use
P R O D U C T H I G H L I G H T
P A C K A G E O R D E R I N F O
Integrated Products Division
for
®
Microsemi
http://www.microsemi.com
current
V i n 6 t o 2 4 V
V i n 6 t o 2 4 V
Mobile AMD Athlon™ VRM Controller
limit and shut
LQ
RoHS Compliant / Pb-free Transition DC: 0512
P
RODUCTION
38-Pin
Plastic MLPQ
LX1676CLQ
High Current Biphase
Operation
Outputs As Low As 0.925V
† Biphase LoadSHARE
† Transient Correction Loop
Reduces Required
Capacitance
Differential Amplifier For
Remote Voltage Sensing
Integrated High Current
MOSFET Drivers
200KHz to 1MHz Frequency
Operation
Programmable Slew Rate
Control For Start-Up Sequence
and VID change
VID Changes On The Fly
Power Good Indicator
Short Circuit Protection
Output Over Voltage and
Under Voltage Protection
No current-sense resistors
AMD Mobile Athlon™ or
Duron™ Processor Core
Voltage Supply
Voltage Regulator Modules
D
ATA
K E Y F E A T U R E S
A P P L I C A T I O N S
S
HEET
V o u t
LX1676
TM
Page 1

Related parts for lx1676

lx1676 Summary of contents

Page 1

... T (°C) J RoHS Compliant / Pb-free Transition DC: 0518 Note: Available in Tape & Reel. Append the letters “TR” to the part number. (i.e. LX1676CLQ-TR) Copyright © 2000 Revision: 1.0, 4/12/2005 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 ® Mobile AMD Athlon™ VRM Controller maximizing regulator response ...

Page 2

... HO1 VS1 GND VIN LO1 ROSC PGN LO2 ENA VID4 VCCL VID3 I-MIN PGN3 VID2 VID1 VCC VID0 VC2 20 VS2 19 HO2 PW P ACKAGE (Top View) RoHS / Pb-free 100% Matte Tin Lead Finish LX1676 Units Min Typ Max 4.5 5.5 V 5 5.5 V Page 2 ...

Page 3

... Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 ® Mobile AMD Athlon™ VRM Controller Description for phase 1. DS(ON) Microsemi Integrated Products Division LX1676 D S RODUCTION ATA HEET Page 3 ...

Page 4

... VIN = =1. 2mA EO2(MAX) EA2 -20uA EO2(MIN) EA2 UGBW Microsemi Integrated Products Division LX1676 RODUCTION ATA HEET ≤ ≤ T 70°C except where A LX1676 Min Typ Max 0 1. -100 100 60 70 0.8 2.5 4.0 0.15 0 0.99 1 1.01 65 ...

Page 5

... VCCL - PGN = 5.0 V, Load = 3300pf at I LOx <500nSec I ILIM1 t CSD(ILIM1) I ILIM3 t CSD(ILIM3 -3mA PWGD PWGD Microsemi Integrated Products Division LX1676 D S RODUCTION ATA HEET ≤ ≤ T 70°C except where A LX1676 Units Min Typ Max -6 6 0.98 1 1.02 60 180 4 MHz 4.8 4.9 0.1 0.2 4.8 4.9 0.1 0.2 1 1.5 ...

Page 6

... Shutdown 11111 Microsemi Integrated Products Division LX1676 D S RODUCTION ATA HEET ≤ ≤ T 70°C except where A LX1676 Units Min Typ Max 4.2 0.3 5.5 0.3 2.35 0.800 1 ≤ DACOUT 1 1.5 0.5 1.3 2 0.3 V (V) OUT 1.275 1.250 1 ...

Page 7

... S S UVLO IMAX + _ 35mV + offset VCCL _ 35mV IMIN _ offset + ENA ILIM PGN3 I-Min VS3 I-Max Microsemi Integrated Products Division LX1676 D S RODUCTION ATA HEET VCCL I-MAX VC1 Q S HO1 R VS1 I-MIN LO1 I-MIN PGN Q R VC2 S HO2 I-MAX VS2 LO2 ...

Page 8

... Q8 IRF7811W C17 0.22µF +5VP Q9 CR5 IRF7822 UPS5817 +5VP C18 C103 10µF 47µF 25V 6.3V Figure 2– Typical VRM Application Microsemi Integrated Products Division LX1676 RODUCTION ATA HEET CR1 SK32 L3 70µH Q4 IRF7811W VBAT C19 C20 C21 C105 10µF 10µF 10µF 10µF ...

Page 9

... URRENT ROTECTION There are two separate current limit circuits in the LX1676. One looks at the phase 1 lower MOSFET drain current and the second looks at the phase 3 upper MOSFET drain current. Both circuits have a 400 nS delay before a current limit command is issued to the current limit latch, once set the current limit latch will hold all three phases off until it is reset ...

Page 10

... DACOUT pin and the PWGD output in high. PWM F REQUENCY An external resistor sets the PWM frequency from the ROSC pin to ground. The equation for ROSC is: where ROSC is in KΩ Hz, K=105e-12 Both Microsemi Integrated Products Division LX1676 RODUCTION ATA HEET 1 ROSC = ...

Page 11

... With the LoadSHARE imbalance the phases so that one phase will supply more current than the other under unique situations. The LX1676 will normally be used with the same supply voltages on phase 1 and 2 PWM inputs and will have equal currents in both phases ...

Page 12

... Under normal operation the Transient Correction phase is only active for a very brief time during high di/dt loads on the output. DACOUT Differential Feedback From Output 35mV 35mV Figure 6 – Phase 3 Transient Correction Loop Microsemi Integrated Products Division LX1676 D S ATA HEET low VC3 + - I-Max I-Max Vout Comparator ...

Page 13

... The D × capacitor should be rated to handle the RMS input current s f requirement. The RMS input current is: Where I The maximum RMS value of 0.25I 25% or 75%. Microsemi Integrated Products Division LX1676 RODUCTION ATA HEET A capacitor that satisfies the ESR ( ) ESR I ∆ ...

Page 14

... The DAC inputs are the Voltage Identification (VID) 0-4 lines, the VID table lists the available output voltages for the corresponding VID codes. There are no external resistor dividers to program output voltage and only the steps listed are available. Microsemi Integrated Products Division LX1676 RODUCTION ATA HEET ...

Page 15

... L e Note: 1. Dimensions do not include mold flash or protrusions; these shall not exceed 0.155mm(.006”) on any side. A dimension shall not include solder coverage Microsemi Integrated Products Division LX1676 D S RODUCTION ATA HEET M I ILLIMETERS NCHES MIN MAX MIN MAX ...

Page 16

... Copyright © 2000 Revision: 1.0, 4/12/2005 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 ® Mobile AMD Athlon™ VRM Controller P RODUCTION Microsemi Integrated Products Division LX1676 D S ATA HEET Page 16 ...

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