Power-Supply Solution. MAX8632 Datasheet

MAX8632 Solution. Datasheet pdf. Equivalent

Part MAX8632
Description Integrated DDR Power-Supply Solution
Feature www.DataSheet4U.com 19-3623; Rev 0; 3/05 KIT ATION EVALU LE B A IL A AV Integrated DDR Power-Suppl.
Manufacture Maxim Integrated Products
Datasheet
Download MAX8632 Datasheet



MAX8632
www.DataSheet4U.com
19-3623; Rev 0; 3/05
EVAALVUAAILTAIOBNLEKIT Integrated DDR Power-Supply Solution
for Desktops, Notebooks, and Graphic Cards
General Description
The MAX8632 integrates a synchronous-buck PWM con-
troller to generate VDDQ, a sourcing and sinking LDO lin-
ear regulator to generate VTT, and a 10mA reference
output buffer to generate VTTR. The buck controller drives
two external n-channel MOSFETs to generate output volt-
ages down to 0.7V from a 2V to 28V input with output cur-
rents up to 15A. The LDO can sink or source up to 1.5A
continuous and 3A peak current. Both the LDO output
and the 10mA reference buffer output can be made to
track the REFIN voltage. These features make the
MAX8632 ideally suited for DDR memory applications in
desktops, notebooks, and graphic cards.
The PWM controller in the MAX8632 utilizes Maxim’s
proprietary Quick-PWM™ architecture with programma-
ble switching frequencies of up to 600kHz. This control
scheme handles wide input/output voltage ratios with
ease and provides 100ns response to load transients
while maintaining high efficiency and a relatively con-
stant switching frequency. The MAX8632 offers fully pro-
grammable UVP/OVP and skip-mode options ideal in
portable applications. Skip mode allows for improved
efficiency at lighter loads.
The VTT and VTTR outputs track to within 1% of VREFIN / 2.
The high bandwidth of this LDO regulator allows excel-
lent transient response without the need for bulk capac-
itors, thus reducing cost and size.
The buck controller and LDO regulators are provided with
independent current limits. Adjustable lossless foldback
current limit for the buck regulator is achieved by monitor-
ing the drain-to-source voltage drop of the low-side
MOSFET. Additionally, overvoltage and undervoltage pro-
tection mechanisms are built in. Once the overcurrent
condition is removed, the regulator is allowed to enter
soft-start again. This helps minimize power dissipation
during a short-circuit condition. The MAX8632 allows flex-
ible sequencing and standby power management using
the SHDN and STBY inputs, which support all DDR
operating states.
The MAX8632 is available in a small 5mm × 5mm, 28-
pin thin QFN package.
Applications
DDR I and DDR II Memory Power Supplies
Desktop Computers
Notebooks and Desknotes
Graphic Cards
Game Consoles
RAID
Networking
Features
Buck Controller
Quick-PWM with 100ns Load-Step Response
Up to 95% Efficiency
2V to 28V Input Voltage Range
1.8V/2.5V Fixed or 0.7V to 5.5V Adjustable Output
Up to 600kHz Selectable Switching Frequency
Programmable Current Limit with Foldback
Capability
1.7ms Digital Soft-Start
Independent Shutdown and Standby Controls
Overvoltage-/Undervoltage-Protection Option
Power-Good Window Comparator
LDO Section
Fully Integrated VTT and VTTR Capability
VTT Has ±3A Sourcing/Sinking Capability
Only 20µF Ceramic Capacitance Required for VTT
VTT and VTTR Outputs Track VREFIN / 2
All-Ceramic Output-Capacitor Designs
1.0V to 2.8V Input Voltage Range
Power-Good Window Comparator
Ordering Information
PART
TEMP RANGE PIN-PACKAGE
MAX8632ETI+
-40°C to +85°C 28 Thin QFN 5mm × 5mm
+Denotes lead-free packaging.
Pin Configuration
TOP VIEW
VDD 22
PGND1 23
GND 24
SKIP 25
AVDD 26
SHDN 27
TPO 28
21 20 19 18 17 16 15
MAX8632
14 REFIN
13 VTTI
12 VTT
11 PGND2
10 VTTR
9 VTTS
8 SS
1 23 4 56 7
5mm x 5mm THIN QFN
Typical Operating Circuit appears at end of data sheet.
Quick-PWM is a trademark of Maxim Integrated Products, Inc.
________________________________________________________________ Maxim Integrated Products 1
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.



MAX8632
www.DataSheet4U.com
Integrated DDR Power-Supply Solution for
Desktops, Notebooks, and Graphic Cards
ABSOLUTE MAXIMUM RATINGS
VIN to GND .............................................................-0.3V to +30V
VDD, AVDD , VTTI to GND .........................................-0.3V to +6V
SHDN, REFIN to GND ..............................................-0.3V to +6V
SS, POK1, POK2, SKIP, ILIM, FB to GND ................-0.3V to +6V
STBY, TON, REF, UVP/OVP to GND ........-0.3V to (AVDD + 0.3V)
OUT, VTTR to GND ..................................-0.3V to (AVDD + 0.3V)
DL to PGND1..............................................-0.3V to (VDD + 0.3V)
DH to LX ....................................................-0.3V to (VBST + 0.3V)
LX to BST..................................................................-6V to +0.3V
LX to GND .................................................................-2V to +30V
VTT to GND...............................................-0.3V to (VVTTI + 0.3V)
VTTS to GND............................................-0.3V to (AVDD + 0.3V)
PGND1, PGND2, TP0 to GND ...............................-0.3V to +0.3V
REF Short Circuit to GND ...........................................Continuous
Continuous Power Dissipation (TA = +70°C)
28-Pin 5mm x 5mm Thin QFN (derate 35.7mW/°C
above +70°C).................................................................2.86W
Operating Temperature Range ...........................-40°C to +85°C
Junction Temperature ......................................................+150°C
Storage Temperature Range .............................-65°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°C
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
ELECTRICAL CHARACTERISTICS
(VIN = +15V, VDD = AVDD = V SHDN = STBY = VBST = VILIM = 5V, VOUT = VREFIN = VVTTI = 2.5V, UVP/OVP = TP0 = FB = SKIP
= GND, PGND1 = PGND2 = LX = GND, TON = OPEN, VVTTS = VVTT, TA = -40°C to +85°C, unless otherwise noted. Typical values
are at TA = +25°C.) (Note 1)
PARAMETER
MAIN PWM CONTROLLER
Input Voltage Range
Output Adjust Range
Output Voltage Accuracy
(Note 2)
Soft-Start Ramp Time
On-Time
Minimum Off-Time
VIN Quiescent Supply Current
VIN Shutdown Supply Current
AVDD Quiescent Supply Current
AVDD + VDD Shutdown Supply
Current
AVDD Undervoltage-Lockout
Threshold
VDD Quiescent Supply Current
SYMBOL
CONDITIONS
VIN
VDD, AVDD
VOUT
FB = OUT
FB = GND
FB = VDD
tSS Rising edge of SHDN to full current limit
VIN = 15V,
tON VOUT = 1.5V
(Note 3)
TON = GND (600kHz)
TON = REF (450kHz)
TON = open (300kHz)
TON = AVDD (200kHz)
tOFF_MIN (Note 3)
IIN
SHDN = GND
IAVDD
All on (PWM, VTT, and VTTR on)
STBY = GND (only VTTR and PWM on)
SHDN = GND
IVDD
Rising edge of VIN
Hysteresis
Set VFB = 0.8V
MIN
2
4.5
0.7
0.693
2.47
1.78
170
213
316
461
200
4.05
TYP
0.7
2.5
1.8
1.7
194
243
352
516
300
25
1
2.5
1
4.25
50
1
MAX UNITS
28
5.5
5.5
0.707
2.53
1.82
219
273
389
571
450
40
5
5
2
20
4.40
5
V
V
V
ms
ns
ns
µA
µA
mA
µA
V
mV
µA
2 _______________________________________________________________________________________







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