MIC4782
1.8 MHz Dual 2A Integrated Switch
Buck Regulator
General Description
Features
The Micrel MIC4782 is a high efficiency dual PWM buck
(step-down) regulator that provides dual 2A output current.
The MIC4782 operates at 1.8MHz. A proprietary internal
compensation technique allows a closed loop bandwidth of
over 200kHz.
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The low on-resistance internal P-Channel MOSFET of the
MIC4782 allows efficiencies over 92%, reduces external
components count and eliminates the need for an
expensive current sense resistor.
The MIC4782 operates from 3.0V to 6.0V input and the
output can be adjusted down to 0.6V. The device can
operate with a maximum duty cycle of 100% for use in lowdropout conditions.
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The MIC4782 is available in the exposed pad 16-pin
3mm x 3mm MLF® with a junction operating range from
–20°C to +125°C.
All support documentation can be found on Micrel’s web
site at: www.micrel.com.
3.0 to 6.0V supply voltage
1.8MHz PWM mode
2A dual output
Greater than 92% efficiency
100% maximum duty cycle
Adjustable output voltage option down to 0.6V
Ultra-fast transient response
Ultra-small external components
Stable with a 1µH inductor and a 4.7µF output
capacitor
Fully integrated 2A MOSFET switches
Micro-power shutdown
Thermal shutdown and current limit protection
Available in a 3mm × 3mm 16-pin MLF®
–20°C to +125°C junction temperature range
Applications
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Broadband: xDSL modems
Automotive satellite radios
HD STB, DVD/TV recorder
Computer peripherals: printers and graphic cards
FPGA/ASIC
General point-of-load
Typical Application
5.0VIN, 3.3VOUT Efficiency
100
98
EFFICIENCY (%)
96
94
92
90
88
86
84
82
80
0
0.4
0.8
1.2
1.6
2
OUTPUT CURRENT (A)
2A, 1.8MHz Dual Buck Regulator
MLF and MicroLeadFrame are registered trademarks of Amkor Technology, Inc.
Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com
August 2009
1
M9999-081709-D
Micrel, Inc.
MIC4782
Ordering Information
Part Number
Voltage
Junction Temp. Range
MIC4782YML
Adj.
–20° to +125°C
Package
16-Pin 3mm x 3mm MLF®
Lead Finish
Pb-Free
Note:
®
MLF is a GREEN RoHS-compliant package. Lead finish is NiPdAu. Mold compound is Halogen Free.
Pin Configuration
16-Pin 3mm x 3mm MLF® (YML)
August 2009
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M9999-081709-D
Micrel, Inc.
MIC4782
Pin Description
Pin Number
Pin Name
1
FB2
Feedback for output 2 (Input). Input to the error amplifier, connect to the external resistor
divider network to set the output voltage.
Pin Function
2(1)
EN2
Enable for output 2 (Input). Logic level low, will shutdown the device, reducing the current
draw to 1.6µA typical. (both EN1 and EN2 are low).
3,4
SW2
Switch for output 2 (Output): Internal power P-Channel MOSFET output switch
5
PGND2
Power Ground for output 2. Provides the ground return path for the high-side drive current.
PGND1 pin and PGND2 pin are internally connected by anti-parallel diodes.
6,15
VIN2
Supply Voltage for output 2 (Input): Supply voltage for the source of the internal P-channel
MOSFET and driver. Requires bypass capacitor-to-GND.
VIN1 pins and VIN2 pins are internally connected by anti-parallel diodes.
7,14
VIN1
Supply Voltage for output 1 (Input): Supply voltage for the source of the internal P-channel
MOSFET and driver. Requires bypass capacitor-to-GND.
VIN1 pins and VIN2 pins are internally connected by anti-parallel diodes.
8
PGND1
Power Ground for output 1. Provides the ground return path for the high-side drive
current.
PGND1 pin and PGND2 pin are internally connected by anti-parallel diodes.
9,10
SW1
Switch for output 1 (Output): Internal power P-Channel MOSFET output switch
11(1)
EN1
Enable for output 1 (Input). Logic level low, will shutdown the device, reducing the current
draw to 1.6µA typical. (both EN1 and EN2 are low).
12
FB1
Feedback for output 1 (Input). Input to the error amplifier, connect to the external resistor
divider network to set the output voltage.
13
SGND
Signal (Analog) Ground. Provides return path for control circuitry and internal reference.
16
BIAS
Internal circuit bias supply. Must be bypassed with a 0.1µF ceramic capacitor-to-SGND.
Biased through a 10Ω resistor to VIN.
EPAD
GND
Connect to ground.
Note:
1. Do not float Enable Input.
August 2009
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M9999-081709-D
Micrel, Inc.
MIC4782
Absolute Maximum Ratings(1)
Operating Ratings(2)
Supply Voltage (VIN) ..................................... –0.3V to +6.5V
Output Switch Voltage (VSW1, VSW2).............. –0.3V to +6.5V
Output Switch Current (ISW1, ISW2)………...Internally Limited
Input Voltage (VEN), (VFB), (VBIAS) .......................-0.3V to VIN
Storage Temperature (Ts) .........................–60°C to +150°C
Junction Temperature ................................................ 150°C
Lead Temperature (soldering, 10sec.)....................... 260°C
ESD Rating(3) ................................................................. 2KV
Supply Voltage (VIN)........................................... +3V to +6V
Logic Input Voltage (VEN) ....................................... 0V to VIN
Junction Temperature (TJ) ........................ –20°C to +125°C
Junction Thermal Resistance
3mm x 3mm MLF® (θJA).....................................60°C/W
Electrical Characteristics(4)
VIN = VEN = 3.6V; L = 1.0µH; COUT = 4.7µF; TA = 25°C, unless noted. Bold values indicate –20°C< TJ < +125°C.
Parameter
Condition
Min
Turn-on
2.45
3.0
Supply Voltage Range
Under-Voltage Lockout Threshold
UVLO Hysteresis
Quiescent Current
Typ
2.6
Max
Units
6.0
V
2.7
V
100
VFB = 0.9 * VNOM (not switching); VIN = 6V
1.4
mV
3.0
mA
VFB = 0.9 * VNOM (not switching); VIN = 3.6V
1.0
mA
Shutdown Current
VEN = 0V
1.6
µA
[Adjustable] Feedback Voltage
± 3%, ILOAD = 100µA
589
FB pin input current
607
625
1
2.5
mV
nA
Current Limit
VFB = 0.9 * VNOM
4.3
A
Output Voltage Line Regulation
VIN = 3V to 6V; ILOAD= 100 µA
0.07
%
Output Voltage Load Regulation
20mA < ILOAD < 2A
0.2
%
Maximum Duty Cycle
VFB ≤ 0.9 * VNOM
Switch ON-Resistance
ISW = 50mA VFB =GND
100
%
155
mΩ
Oscillator Frequency
1.8
MHz
Switching Phase
180
Deg
0.5
Enable Threshold
0.9
1.3
V
Enable Hysteresis
55
mV
Enable Input Current
0.1
µA
Over-Temperature Shutdown
153
°C
Over-Temperature Hysteresis
18
°C
Notes:
1. Exceeding the absolute maximum rating may damage the device.
2. The device is not guaranteed to function outside its operating rating.
3. Devices are ESD sensitive. Handling precautions recommended. Human body model, 1.5k in series with 100pF.
4. Specification for packaged product only.
August 2009
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M9999-081709-D
Micrel, Inc.
MIC4782
Typical Characteristics
3.3VIN, 1.0VOUT Efficiency
5.0VIN, 1.0VOUT Efficiency
80
82
76
76
80
74
74
78
70
68
66
72
70
68
66
64
3.0Vin
64
62
3.3Vin
3.6Vin
62
60
0
0.4
0.8
1.2
1.6
EFFICIENCY (%)
78
72
4.5Vin
5.5Vin
70
2
0.4
0.8
1.2
1.6
2
3.3VIN, 1.5VOUT Efficiency
88
84
76
74
72
70
82
80
78
76
74
68
4.5Vin
72
66
5.0Vin
5.5Vin
70
1.6
EFFICIENCY (%)
86
84
78
3.0Vin
80
78
76
74
0.4
0.8
1.2
1.6
2
5.0VIN, 1.8VOUT Efficiency
86
90
80
78
3.0Vin
1.2
1.6
80
78
4.5Vin
5.5Vin
0
0.4
5.0VIN, 2.5VOUT Efficiency
96
90
94
EFFICIENCY (%)
98
92
88
86
84
82
4.5Vin
5.0Vin
78
1.6
0.8
1.2
August 2009
3.0Vin
3.3Vin
3.6Vin
0
0.4
0.8
1.6
2
1.2
1.6
2
OUTPUT CURRENT (A)
Load Regulation
0.615
88
86
4.5Vin
0.610
0.605
0.600
5.0Vin
Vin=3.3V
5.5Vin
0.595
80
OUTPUT CURRENT (A)
82
2
90
82
5.5Vin
0.4
84
76
92
84
76
0
86
5.0VIN, 3.3VOUT Efficiency
100
94
80
1.2
2
88
OUTPUT CURRENT (A)
OUTPUT CURRENT (A)
96
0.8
1.6
78
72
2
1.2
80
5.0Vin
74
3.6Vin
72
82
76
3.3Vin
74
84
OUTPUT VOLTAGE (V)
76
EFFICIENCY (%)
92
86
EFFICIENCY (%)
94
88
82
0.8
3.3VIN, 2.5VOUT Efficiency
96
90
0.8
0.4
OUTPUT CURRENT (A)
88
0.4
5.5Vin
0
90
0
4.5Vin
5.0Vin
68
92
84
2
82
OUTPUT CURRENT (A)
3.3VIN, 1.8VOUT Efficiency
1.6
70
3.6Vin
0
OUTPUT CURRENT (A)
92
1.2
72
3.3Vin
68
2
0.8
5.0VIN, 1.5VOUT Efficiency
88
86
1.2
0.4
OUTPUT CURRENT (A)
80
0.8
3.6Vin
0
82
0.4
3.0Vin
3.3Vin
64
0
EFFICIENCY (%)
EFFICIENCY (%)
72
66
60
5.0VIN, 1.2VOUT Efficiency
0
EFFICIENCY (%)
74
OUTPUT CURRENT (A)
64
EFFICIENCY (%)
76
68
5.0Vin
OUTPUT CURRENT (A)
84
3.3VIN, 1.2VOUT Efficiency
84
78
EFFICIENCY (%)
EFFICIENCY (%)
80
0
0.4
0.8
1.2
1.6
OUTPUT CURRENT (A)
5
2
0
0.4
0.8
1.2
1.6
2
OUTPUT CURRENT (A)
M9999-081709-D
Micrel, Inc.
MIC4782
Typical Characteristics (continue)
Feedback Voltage
0.610
2.2
0.6076
0.608
2.1
0.607
2.0
0.6072
0.6070
0.6068
0.6066
FREQUENCY (MHz)
0.609
0.6074
0.606
0.605
0.604
0.603
1.9
1.8
1.7
1.6
0.602
1.5
0.6062
0.601
1.4
0.6060
0.600
0.6064
3
3.6
4.2
4.8
5.4
6
1.3
-20
0
20
SUPPLY VOLTAGE (V)
40
60
80
100
-20
120
0
20
Quiescent Current
vs. Supply Voltage
1.6
40
60
80
100
120
TEMPERATURE (°C)
TEMPERATURE (°C)
Feedback Voltage
vs. Supply Voltage
0.8
Frequency
vs. Temperature
2.3
0.6078
FEEDBACK VOLTAGE (V)
FEEDBACK VOLTAGE (V)
0.6080
Feedback Voltage
vs. Temperature
Rdson
vs. Supply Voltage
190
0.4
0.2
0.0
1.2
170
Rdson (mΩ)
QUIESCENT CURRENT (mA)
FEEDBACK VOLTAGE (V)
180
0.6
0.8
1
2
3
4
5
6
110
0
1
2
4
5
ENABLE THRESHOLD (V)
180
170
160
150
140
130
1.20
1.2
1.00
1.0
0.80
0.60
0.40
0.20
0.00
120
40
60
80
TEMPERATURE (°C)
August 2009
3.6
100
120
4.2
4.8
5.4
6
SUPPLY VOLTAGE (V)
ENABLE THRESHOLD (V)
190
20
3
6
Enable Threshold
vs. Supply Voltage
200
Rdson (mΩ)
3
SUPPLY VOLTAGE (V)
Rdson
vs. Temperature
0
140
120
SUPPLY VOLTAGE (V)
-20
150
130
0.4
0.0
0
160
Enable Threshold
vs. Temperature
0.8
0.6
0.4
0.2
0.0
3
3.6
4.2
4.8
SUPPLY VOLTAGE (V)
6
5.4
6
-20
0
20
40
60
80
100
120
TEMPERATURE (°C)
M9999-081709-D
Micrel, Inc.
MIC4782
Functional Characteristics
August 2009
7
M9999-081709-D
Micrel, Inc.
MIC4782
Functional Diagram
MIC4782 Block Diagram
August 2009
8
M9999-081709-D
Micrel, Inc.
MIC4782
Pin Description
SW1/SW2
The switch pins (SW1 and SW2) connect directly to the
inductor and provide the switching current necessary to
operate in PWM mode. Due to the high speed switching
on these pins, the switch nodes should be routed away
from sensitive nodes. These pins also connect to the
cathodes of the free-wheeling diodes.
VIN1/VIN2
VIN pins (two pins for VIN1 and two pins for VIN2)
provide power to the source of the internal P-Channel
MOSFET along with the current limiting sensing. VIN1
pins and VIN2 pins are internally connected by antiparallel diodes. The VIN operating voltage range is from
3.0V to 6.0V. Due to the high switching speeds, a 10µF
capacitor is recommended close to VIN and the power
ground (PGND) for each pin for bypassing. Please refer
to layout recommendations for more details.
PGND1/PGND2
Power ground pins (PGND1 and PGND2) are the ground
paths for the MOSFET drive current. PGND1 pin and
PGND2 pin are internally connected by anti-parallel
diodes. The current loop for the power ground should be
as small as possible and separate from the Signal
ground (SGND)
loop.
Refer
to
the
layout
recommendation for more details.
BIAS
The bias (BIAS) provides power to the internal reference
and control sections of the MIC4782. A 10Ω resistor
from VIN to BIAS and a 0.1µF from BIAS to SGND are
required for clean operation.
SGND
Signal ground (SGND) is the ground path for the biasing
and control circuitry. The current loop for the signal
ground should be separate from the power ground
(PGND) loop. Refer to the layout recommendation for
more details.
EN1/EN2
The enable pins (EN1 and EN2) provides a logic level
control of the outputs 1 and 2. In the off state, supply
current of the device is greatly reduced (typically
