EL7556AC Datasheet, PDF (1/13 Pages) Elantec Semiconductor – Programmable CPU Power Supply Unit

EL7556AC
Programmable CPU Power Supply Unit
Features
• EL7556C Pin Compatible
• Improved Temperature and
Voltage Ranges
• 6A Continuous Load Current
• Precision Internal 1% Reference
• 1.0V to 3.8V Output Voltage
• Internal Power MOSFETs
• >90% Efficiency
• Synchronous Switching
• Adjustable Slope Compensation
• Over Temperature Indicator
• Pulse by Pulse Current Limiting
• Operates up to 1MHz
• 1.5% Typical Output Accuracy
• Adjustable Oscillator w/Sync
• Remote Enable/Disable
• Intel P54 and P55 Compatible
• VCC2DET Interface
• Internal Soft Start
Applications
• PC Motherboards
• Local high power CPU supplies
• 5V to 1.0V DC-DC Conversion
• Portable Electronics/Instruments
• P54 and P55 Regulators
• GTL+ Bus Power Supply
Ordering Information
Part No Temp. Range
Package
EL7556ACM -40°C to +85°C 28-Lead SOIC
Outline #
MDP0027
General Description
The EL7556AC is an adjustable synchronous DC:DC switching regu-
lator optimized for a 5V input and 1.0-3.8V output. By combining
integrated NMOS power FETS with a fused-lead package the
EL7556AC can supply up to 6A continuous output current without the
use of external power devices or discrete heat sinks, thereby minimiz-
ing design effort and overall system cost.
On chip resistorless current sensing is used to achieve stable, highly
efficient, current-mode control. The EL7556AC also incorporates the
VCC2DET function to directly interface with the Intel P54 and P55
microprocessors. Depending on the state of VCC2DET the output
voltage is internally preset to 3.50V or a user adjustable voltage using
two external resistors. In both internal and external feedback modes
the active-high PWRGD output indicates when the regulator output is
within ±10% of the programmed voltage. An on-board sensor moni-
tors die temperature (OT) for over-temperature conditions and can be
connected directly to OUTEN to provide automatic thermal shutdown.
Adjustable oscillator frequency and slope compensation allow added
flexibility in overall system design.
Connection Diagram
VIN
R4
100Ω
R3
150Ω
C4 0.1µF
C7 150pF
C8 220pF
R5
5Ω
1 FB1
FB2 28
2 CREF
CP 27
3 CSLOPE C2V 26
4 COSC
VSS 25
5 VDD
VHI 24
6 VIN
LX 23
7 VSSP
LX 22
C9
660µF
C12
0.1µF
C3
1µF
8 VIN
LX 21
9 VSSP
LX 20
10 VSSP VSSP 19
11 VSSP VSSP 18
Connect to VSSP for
external feedback
12 VSSP TEST 17
13
VCC2DET
PWRGD
16
14 OUTEN
OT 15
VIN
D3
C5
R1
1µF
68Ω
R6
C 6 68Ω
0.1µF
D2
D1
D4
C11
0.22µF
L1 2.5µH
C10
1mF
VOUT
C3, C4, C5, C6, C7 C8 - ceramic
C5, C11 - ceramic or tantalum
C9 - Sprague 594D337X10010R2T 2X330µF
C10 - Sprague 594D337X10010R2T 3X330µF
L1 - Pulse Engineering, PE-53681
D1-D4: BAT54S fast diode
EL7556AC
Manufactured under U.S. Patents No. 5,723,974 and No. 5,793,126
Note: All information contained in this data sheet has been carefully checked and is believed to be accurate as of the date of publication; however, this data sheet cannot be a “controlled document”. Current revisions, if any, to these
specifications are maintained at the factory and are available upon your request. We recommend checking the revision level before finalization of your design documentation.
© 2000 Elantec, Inc.