ELANT EL7556BCM-T13, EL7556BCM Datasheet
EL7556BC
Integrated Adjustable 6 Amp Synchronous Switcher
EL7556BC
Features
• EL7556C/EL7556AC Pincompatible
• 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 with 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 Package
EL7556BCM 28-Pin SO - MDP0027
EL7556BCM-T13 28-Pin SO 13” MDP0027
Tape &
Reel Outline #
General Description
The EL7556BC is an adjustable synchronous DC:DC switching regulator optimized for a 5V input and 1.0V-3.8V output. By combining
integrated NMOS power FETS with a fused-lead package, the
EL7556BC can supply up to 6A continuous output current without the
use of external power devices or discrete heat sinks, thereby minimizing design effort and overall system cost.
On-chip resistorless current sensing is used to achieve stable, highly
efficient, current-mode control. The EL7556BC 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 3.5V 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 monitors 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.
The EL7556BC is available in a 28-pin SO package and is specified
for operation over the full -40°C to +85°C temperature range.
Connection Diagram
C4
R5
5.1Ω
C9
V
IN
660µF
C3
1µF
C12 - 1µF
C3, C4, C5, C6, C7 C8 - ceramic
C5, C11 - ceramic or tantalum
C9 - Sprague 293D337X96R3 2X330µF
C10 - Sprague 293D337X96R3 3X330µF
L1 - Pulse Engineering, PE-53681
D1-D4: BAT54S fast diode
D4 Required for EL7556ACM Only
Manufactured under U.S. Patents No. 5,723,974 and No. 5,793,126
R4 R3
100Ω 150Ω
0.1µF
C7
Connect to VSSP for
external feedback
1
2
39pF
3
C8
220pF
4
5
6
7
C12
8
1µF
9
10
11
12
13
FB1
CREF
C2V
CSLOPE
VSS
COSC
VDD
VIN
VSSP
VIN
VSSP
VSSP
VSSP
VSSP
VSSP
TEST
VSSP
VCC2DET
PWRGD
OUTEN
EL7556BC
28
FB2
CP
VHI
LX
LX
LX
LX
OT
C 5
27
1µF
R1
26
20Ω
25
R6
24
39.2Ω
C 6
23
0.1µF
22
L1
2.5µH
21
20
19
18
17
16
1514
V
IN
D3
D2
D4*
(Optional)
D1
C11
0.22µF
V
OUT =
C10
1mF
1V*(1+R3/R4)
October 5, 2001
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.
© 2001 Elantec Semiconductor, Inc.
EL7556BC
Integrated Adjustable 6 Amp Synchronous Switcher
EL7556BC
Absolute Maximum Ratings (T
Storage Temperature Range -65°C to +150°C
Supply (VIN) 6.0V
Ambient Operating Temperature -40°C to +85°C
= 25°C)
A
Output Pins -0.3V below GND, +0.3V above VDD
Operating Junction Temperature 135°C
Peak Output Current 9A
Important Note:
All parameters having Min/Max specifications are guaranteed. Typ values are for information purposes only. Unless otherwise noted, all tests are at the
specified temperature and are pulsed tests, therefore: TJ = TC = TA.
Electrical Characteristics
V
= VIN = 5V, C
DD
Parameter Description Conditions Min Typ Max Unit
General
I
DD
I
DDOFF
I
VIN
V
OUT1
V
OUT2
V
OUTLINE
V
OUTLOAD
R
SHORT
I
I MAX
V
OUTTC
T
OT
T
HYS
V
PWRGD
V
DDOFF
V
DDON
V
HYS
M
SS
D
MAX
Controller - Inputs
I
PUP
I
CSLOPE
I
FB1
R
OT
V
IH
V
IL
VOH
PWGD
V
OL PWGD
Controller - Reference
V
REF
V
REFTC
V
REFLOAD
= 1nF, C
OSC
VDD Supply Current OUTEN = 4V, F
= 470pF, TA = 25°C unless otherwise specified.
SLOPE
= 120kHz 11 25 mA
OSC
VDD Standby Current OUTEN = 0 0.1 mA
V
No Load Current OUTEN = 0 3 5 mA
IN
Output Initial Accuracy VCC2DET = 4V, IL = 3A (See Fig. 1) 3.450 3.500 3.550 V
Output Initial Accuracy VCC2DET = 0V, IL = 3A R
100Ω (See Fig. 1)
= 150Ω, R
3
=
2.450 2.500 2.550 V
4
Output line Regulation VDD = 5V, ±10% -1 1 %
Output Load Regulation 0A<I
Short Circuit Load Resistance IL = 6A, Prior to Continuous Application of
<6A, Relative to IL = 3A. Continu-
LOAD
ous Mode of Operation (See Fig.1)
R
. OUTEN Connected to OT.
SHORT
-1 1 %
100 mΩ
Current Limit 9 A
Output Tempco -40°C<TA<85°C ±1 %
Over Temperature Threshold 135 °C
Over Temperature Hysteresis 40 °C
Power Good Threshold Relative to Programmed
Output Voltage
VCC2SEL = 4V, V
= 3.50V ±6 ±10 ±14 %
OUT
Minimum VDD for Shutdown 3.15 V
Maximum VDD for Startup 4.15 V
Input Hysteresis V
HYS
= V
DDON-VDDOFF
0.5 V
Soft start slope 7 V/mS
Maximum duty cycle 96 %
VCC2DET, OUTEN Pull Up Current VCC2DET, OUTEN = 0 10 14 18 µA
Cslope Charging Current 23 28.5 34 µA
FB1 Input Pull Up Current 2 µA
Over Temperature Pull Up Resistance OT = 0V 30 40 50 kΩ
VCC2DET, OUTEN Input High 4 V
VCC2DET, OUTEN Input Low 0.8 V
Powergood Drive High I
Powergood Drive Low I
Reference Accuracy I
= 1mA 3.5 V
LOAD
= -1mA 1.0 V
LOAD
= 0 1.247 1.260 1.273 V
REF
Reference Voltage Tempco 50 ppm/ºC
Reference Load Regulation 0<I
<100µA 0.5 0.5 %/ºC
LOAD
2
EL7556BC
Integrated Adjustable 6 Amp Synchronous Switcher
Electrical Characteristics
V
= VIN = 5V, C
DD
Parameter Description Conditions Min Typ Max Unit
Controller - Doubler
V
C2V
Controller - Oscillator
F
RAMP
I
OSC CHG
I
OSC DIS
F
OSC
t
SYNC
Power - FET
I
LEAK
R
DSON
R
DSONTC
t
BRM
t
LEB
= 1nF, C
OSC
Voltage Doubler Output V
Oscillator Ramp Amplitude 1.2 V
Oscillator Charge Current 0.2V<V
Oscillator Discharge Current 0.2V<V
Oscillator initial accuracy 100 120 140 kHz
Minimum oscillator sync width 50 ns
LX Output Leakage to VSS LX = 0V 100 µA
Composite FET Resistance 18 30 mΩ
R
Tempco 0.1 mΩ/ºC
DSON
FET break before make delay 10 ns
High side FET minimum on time (LEB) 140 ns
= 470pF, TA = 25°C unless otherwise specified.
SLOPE
DD
= 5V, I
= 10mA 7.5 8.1 8.7 V
LOAD
<1.4V 150 µA
OSC
<1.4V 5 mA
OSC
EL7556BC
3
EL7556BC
Integrated Adjustable 6 Amp Synchronous Switcher
EL7556BC
Typical Performance Curves
Efficiency vs I
VDD=VIN=5.0V (±10%)
96
94
LOAD
(V
=3.5V)
OUT
VDD=4.5V
92
90
VDD=5V
88
VDD=5.5V
86
Efficiency (%)
84
82
80
0.5 1.5 2.5 3.5 4.5 5.5
Line Regulation (C
SLOPE
I
OUT
=100pF)
(A)
3.54
3.53
3.52
I
=0.5A
3.51
(V)
3.50
OUT
V
3.49
OUT
I
OUT
=3A
3.48
I
=6A
3.47
3.46
4.5 5.0 5.5
OUT
VIN (V)
TA=25°C
TA=25°C
Efficiency vs I
(VDD=5.0V)
LOAD
100
95
90
VCC=3.5V
VCC=2.5V
85
Efficiency (%)
80
VCC=1V
75
6.5
70
0.5
1.5
Load Regulation (C
2.5 3.5 4.5 6.0
I
(A)
OUT
=100pF)
SLOPE
5.5
3.54
3.53
3.52
3.51
(V)
3.50
OUT
V
3.49
VIN=5V
VIN=5.5V
3.48
OUT
VIN=4.5V
(A)
3.47
TA=25°C
3.46
0.5 3.0 6.0
I
Line Regulation vs C
VDD=VIN=5.0V ±10%
0.8
0.7
0.6
0.5
(±) (%)
0.4
OUT
0.3
∆V
0.2
0.1
0.0
50 75
(I
=3A)
SLOPE
OUT
TA=25°C
V
=3.5A
OUT
V
=2.5A
OUT
V
=1A
OUT
100 125 150 175
C
(pF)
SLOPE
Load Regulation vs C
I
=3A, +3A, -2.5A
OUT
0.6
SLOPE (VIN
=5.0V)
TA=25°C
0.5
V
=3.5A
0.4
(±) (%)
0.3
OUT
∆V
0.2
OUT
V
=2.5A
OUT
V
=1A
OUT
0.1
0.0
50 75 100 125 150 175
C
SLOPE
(pF)
4
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