FAIRCHILD FAN2012IMPX

FAN2011/FAN2012
1.5A Low Voltage Current Mode Synchronous PWM Buck
Regulator
Features
Description
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The FAN2011/FAN2012 is a high-efficiency, low-noise synchronous PWM current mode DC-DC converter, designed for low
voltage applications. It provides up to 1.5A continuous load current from the 4.5V to 5.5V input. The output voltage is adjustable over a wide range of 0.8V to VIN by means of an external
voltage divider.
95% Efficiency, Synchronous Operation
Adjustable Output Voltage from 0.8V to VIN
4.5V to 5.5V Input Voltage Range
Up to 1.5A Output Current
Fixed Frequency 1.3 MHz PWM Operation
100% Duty Cycle Low Dropout Operation
Soft Start
Excellent Load Transient Response
3x3mm 6-lead MLP Package
The FAN2011 is always on, while the FAN2012 has an “Enable
Input,” and the device can be put in the shutdown mode, in
which the ground current falls below 1µA.
A current mode control loop with a fast transient response
ensures excellent line and load regulation. The fixed 1.3MHz
switching frequency enables the user to choose a small, inexpensive external inductor and capacitor. Filtering is also easily
accomplished with very small components.
Applications
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Hard Disk Drive
Set Top Box
Point of Load Power
Notebook Computers
Communications Equipment
Protection features include input under-voltage lockout, short
circuit protection and thermal shutdown. Soft-start limits in-rush
current during start-up conditions.
The device is available in a 3x3mm 6-lead MLP package, making it possible to build a 1.5A complete DC/DC converter in a
tiny space on the PCB.
Typical Application
FB 1
R2
6
10KΩ
PGND
R1
VOUT
L1
2
P1
(AGND)
5
SW
3
4
3.3µH
VIN
EN
FB 1
NC
+5V
R2
PGND
R1
L1
VOUT
PVIN
6
10KΩ
SW
2
P1
(AGND)
3
4
3.3µH
10µF
FAN2011
VIN
+5V
PVIN
10µF
4 x 10µF
4 x 10µF
5
FAN2012
Figure 1. Typical Application
FAN2011/FAN2012 Rev. 1.0.2
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FAN2011/FAN2012 1.5A Low Voltage Current Mode Synchronous PWM Buck Regulator
November 2004
Top View
FB
1
PGND
2
SW
3
6
P1
(AGND)
FB
NC
5
VIN
4
PVIN
1
PGND
2
SW
3
FAN2011
3x3mm 6-Lead MLP
P1
(AGND)
6
EN
5
VIN
4
PVIN
FAN2012
3x3mm 6-Lead MLP
Figure 2. Pin Assignment
Pin Description
FAN2011 (3x3mm 6-Lead MLP)
Pin No.
Pin Name
P1
AGND
Pin Description
Analog Ground. P1 must be soldered to the PCB ground.
1
FB
2
PGND
Feedback Input. Adjustable voltage option, connect this pin to the resistor divider.
3
SW
Switching Node. This pin is connected to the internal MOSFET switches.
Supply Voltage Input. This pin is connected to the internal MOSFET switches.
Power Ground. This pin is connected to the internal MOSFET switches. This pin must be externally connected to AGND.
4
PVIN
5
VIN
Supply Voltage Input.
6
NC
Not Connected. This pin is not internally connected.
FAN2012(3x3mm 6-Lead MLP)
Pin No.
Pin Name
P1
AGND
1
FB
2
PGND
Pin Description
Analog Ground. P1 must be soldered to the PCB ground.
Feedback Input. Adjustable voltage option, connect this pin to the resistor divider.
Power Ground. This pin is connected to the internal MOSFET switches. This pin must be externally connected to AGND.
3
SW
Switching Node. This pin is connected to the internal MOSFET switches.
4
PVIN
Supply Voltage Input. This pin is connected to the internal MOSFET switches.
5
VIN
Supply Voltage Input.
6
EN
Enable Input. Logic high enables the chip and logic low disables the chip, reducing the supply
current to less than 1µA. Do not float this pin.
FAN2011/FAN2012 Rev. 1.0.2
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FAN2011/FAN2012 1.5A Low Voltage Current Mode Synchronous PWM Buck Regulator
Pin Assignment
Parameter
Min
Max
Unit
VIN
-0.3
7
V
PVIN and any other pin
-0.3
VIN
V
8
°C/W
260
°C
Thermal Resistance-Junction to Tab (θJC), 3mmx3mm 6-lead MLP (Note 2)
Lead Soldering Temperature (10 seconds)
Storage Temperature
-65
150
°C
Junction Temperature
-40
150
°C
Electrostatic Discharge (ESD) Protection Level (Note 3)
HBM
4
CDM
2
Min
Typ
kV
Recommended Operating Conditions
Parameter
Supply Voltage Range
4.5
Output Voltage Range, Adjustable Version
0.8
Output Current
Max
Unit
5.5
V
VIN
V
1500
mA
Inductor (Note 4)
3.3
µH
Input Capacitor (Note 4)
10
µF
Output Capacitor (Note 4)
Operating Ambient Temperature Range
µF
4 x 10
FAN2011 and FAN2012
0
+85
FAN2011I and FAN2012I
-40
+85
°C
Notes:
1. Stresses above those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. This
is a stress rating only and functional operation of the device at these or any other conditions above those indicated
in the operational section of this specification is not implied. Exposure to absolute maximum rating conditions for
extended periods may affect device reliability. Absolute maximum ratings apply individually only, not in combination.
Unless otherwise specified, all other voltages are referenced to AGND.
2. Junction to ambient thermal resistance, θJA, is a strong function of PCB material, board thickness, thickness and
number of copper planes, number of via used, diameter of via used, available copper surface, and attached heat
sink characteristics.
3. Using Mil Std. 883E, method 3015.7(Human Body Model) and EIA/JESD22C101-A (Charge Device Model).
4. Refer to the applications section for further details.
FAN2011/FAN2012 Rev. 1.0.2
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FAN2011/FAN2012 1.5A Low Voltage Current Mode Synchronous PWM Buck Regulator
Absolute Maximum Ratings (Note1)
VIN = 4.5V to 5.5V, VOUT = 1.2V, IOUT = 200mA, CIN = 10µF, COUT = 4 x 10µF, L = 3.3µH, TA = 0°C to
+85°C, unless otherwise noted. Typical values are at TA = 25°C.
Parameter
Conditions
Min.
Input Voltage
Typ.
Max.
4.5
Quiescent Current
IOUT = 0mA
UVLO Threshold
VIN rising
3.5
Units
5.5
V
7
10
mA
3.7
3.9
Hysteresis
150
V
mV
PMOS On Resistance
VIN = VGS = 5V
150
290
mΩ
NMOS On Resistance
VIN = VGS = 5V
150
290
mΩ
P-channel Current Limit
4.5V < VIN < 5.5V
2600
3500
mA
Over-Temperature Protection
Rising temperature
150
Hysteresis
20
2200
Switching Frequency
1000
°C
°C
1300
Line Regulation
VIN = 4.5 to 5.5V, IOUT = 100mA
0.16
Load Regulation
0mA ≤ IOUT ≤ 1500mA
0.2
Output Voltage During Load Transition
(Note 5)
IOUT from 700mA to 100mA
Output Voltage During Load Transition
(Note 5)
IOUT from 100mA to 700mA
Reverse Leakage Current Into Pin SW
VIN = Open, EN = GND, Vsw = 5.5V
1600
kHz
%/V
0.5
%
5
%
-5
%
0.1
Reference Voltage, VREF
1
µA
0.8
Output Voltage Accuracy
VIN = 4.5 to 5.5V
0mA ≤ IOUT ≤ 1500mA
V
FAN2011
FAN2012
-2
2
%
FAN2011I
FAN2012I
-40°C to +85°C
-3
3
%
Additional Electrical Characteristics for FAN2012
TA = 0°C to +85°C, VIN = 4.5 to 5.5V. Typical values are at TA = 25°C.
Parameter
Conditions
Shutdown Mode Supply Current
Min.
Typ.
VEN = 0V
0.1
EN Bias Current
EN High Voltage
Max.
Units
1
µA
0.1
µA
1.3
V
EN Low Voltage
0.4
V
ILOAD (mA)
Notes:
5. Load transient response test waveform.
700
t r = 67nS
100
t f = 67nS
ss
0
0.6
4.6
Time (mSec)
Figure 3. Load Transient Response Test Waveform
FAN2011/FAN2012 Rev. 1.0.2
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FAN2011/FAN2012 1.5A Low Voltage Current Mode Synchronous PWM Buck Regulator
Electrical Characteristics
TA = 25°C, CIN = 10µF, COUT = 40µF, L = 3.3µH, VIN = 5V, unless otherwise noted.
Switching Frequency vs. Ambient Temperature
Output Voltage vs. Ambient Temperature
1260
Temp
Temp
Temp
Temp
Temp
Output Voltage (V)
1.212
1.210
1.208
(∞C)
(∞C)
(∞C)
(∞C)
(∞C)
vs
vs
vs
vs
vs
Switching Frequency (KHz)
1.214
[email protected] 0 mA
[email protected] 100mA
[email protected] 500 mA
[email protected] 1000 mA
[email protected] 1500 mA
1.206
1.204
1.202
1.200
1.198
1.196
1.194
-40
-20
0
20
40
60
80
100
120
1255
1250
1245
1240
1235
1230
0
Ambient Temperature (°C)
20
40
60
80
100
120
Ambient Temperature (°C)
Efficiency vs. Load Current
Power Efficiency (%)
100
VOUT = 3.3V
90
80
VOUT = 1.2V
70
VIN = 4.5V
60
VIN = 5V
50
40
VIN = 5.5V
30
10
100
1000
10000
Load Current (mA)
FAN2011/FAN2012 Rev. 1.0.2
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FAN2011/FAN2012 1.5A Low Voltage Current Mode Synchronous PWM Buck Regulator
Typical Performance Characteristics
TA = 25°C, CIN = 10µF, COUT = 40µF, L = 3.3µH, VIN = 5V, unless otherwise noted.
Start-up Response
Start-up Response
Input
Voltage
(5V/div)
Input
Voltage
(5V/div)
SW Node
Voltage
(5V/div)
SW Node
Voltage
(5V/div)
Inductor
Current
(200mA/div)
Inductor
Current
(200mA/div)
Output
Voltage
(500mV/div)
Output
Voltage
(1V/div)
VOUT = 1.2V
IOUT = 100mA
VOUT = 3.3V
IOUT = 100mA
Time (100µs/div)
Time (50µs/div)
Start-up Response
Start-up Response
Input
Voltage
(5V/div)
Input
Voltage
(5V/div)
SW Node
Voltage
(5V/div)
SW Node
Voltage
(5V/div)
Inductor
Current
(500mA/div)
Inductor
Current
(500mA/div)
Output
Voltage
(500mV/div)
Output
Voltage
(1V/div)
VOUT = 1.2V
IOUT = 1500mA
VOUT = 3.3V
IOUT = 1500mA
Time (100µs/div)
Time (100µs/div)
Transient Response
Transient Response
700mA
Load
Current
Load
Current
100mA
100mA
SW Node
Voltage
(5V/div)
SW Node
Voltage
(5V/div)
Output
Voltage
(20mV/div)
Output
Voltage
(20mV/div)
Inductor
Current
(200mA/div)
700mA
VOUT = 1.2V
Inductor
Current
(200mA/div)
VOUT = 1.2V
Time (5µs/div)
Time (5µs/div)
FAN2011/FAN2012 Rev. 1.0.2
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FAN2011/FAN2012 1.5A Low Voltage Current Mode Synchronous PWM Buck Regulator
Typical Performance Characteristics (Continued)
VIN
EN
DIGITAL
SOFT START
IS
UNDER VOLTAGE
LOCKOUT
CURRENT
SENSE
FB
ERROR
AMP
LOGIC
CONTROL
COMP
MOSFET
DRIVER
SW
0.8V
GND
IS
OVER
VOLTAGE
COMP
OSC
SLOPE COMPENSATION
REF
FB
GND
Figure 4. Block Diagram
Detailed Operation Description
The FAN2011 has an internal soft-start circuit that limits the inrush current during start-up. This prevents possible voltage
drops of the input voltage and eliminates the output voltage
overshoot. The soft-start is implemented as a digital circuit
increasing the switch current in four steps to the P-channel current limit (2600mA). Typical start-up time for a 40µF output
capacitor and a load current of 1500mA is 800µs.
The FAN2011 is a step-down pulse width modulated (PWM)
current mode converter with a typical switching frequency of 1.3
MHz. At the beginning of each clock cycle, the P-channel transistor is turned on. The inductor current ramps up and is monitored via an internal circuit. The P-channel switch is turned off
when the sensed current causes the PWM comparator to trip
when the output voltage is in regulation or when the inductor
current reaches the current limit (set internally to typically
2600mA). After a minimum dead time, the N-channel transistor
is turned on and the inductor current ramps down. As the clock
cycle is completed, the N-channel switch is turned off and the
next clock cycle starts. The duty cycle is solely given by the ratio
of output voltage and input voltage. Therefore, the converter
runs with a minimum duty cycle when output voltage is at minimum and input voltage is at maximum.
Short Circuit Protection
The switch peak current is limited cycle by cycle to a typical
value of 2600mA. In the event of an output voltage short circuit,
the device operates with a frequency of 400kHz and minimum
duty cycle, therefore the average input current is typically
350mA.
Thermal Shutdown
When the die temperature exceeds 150°C, a reset occurs and
will remain in effect until the die cools to 130°C, at that time the
circuit will be allowed to restart.
100% Duty Cycle Operation
As the input voltage approaches the output voltage and the duty
cycle exceeds the typical 95%, the converter turns the P-channel transistor continuously on. In this mode the output voltage is
equal to the input voltage minus the voltage drop across the Pchannel transistor:
Applications Information
Setting the Output Voltage
VOUT = VIN – ILOAD × (RDS_ON + RL), where
The internal reference is 0.8V. The output is divided down by a
voltage divider, R1 and R2 to the FB pin. The output voltage is:
RDS_ON = P-channel switch ON resistance
ILOAD = Output current
RL = Inductor DC resistance
R
V OUT = V REF  1 + ------1-

R 
2
According to this equation, and assuming desired output voltage of 1.5096V, and given R2 = 10KΩ, the calculated value of
R1 is 8.87KΩ.
UVLO and Soft Start
The reference and the circuit remain reset until the VIN crosses
its UVLO threshold.
FAN2011/FAN2012 Rev. 1.0.2
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FAN2011/FAN2012 1.5A Low Voltage Current Mode Synchronous PWM Buck Regulator
Block Diagram
Inductor Selection
The inductor parameters directly related to device performances
are saturation current and dc resistance. The FAN2011/
FAN2012 operates with a typical inductor value of 3.3µH. The
lower the dc resistance, the higher the efficiency. For saturation
current, the inductor should be rated higher than the maximum
load current plus half of the inductor ripple current that is calculated as follows:
∆I L = V OUT
1 – ( V OUT ⁄ V IN )
× -----------------------------------------L×f
where:
∆IL = Inductor Ripple Current
f = Switching Frequency
L = Inductor Value
Some recommended inductors are suggested in the table
below:
Inductor Value
Vendor
Part Number
3.3µH
Panasonic
ELL6PM3R3N
3.3µH
Murata
LQS66C3R3M04
Figure 5. Recommended PCB Layout
Table 1: Recommended Inductors
Capacitors Selection
For best performances, a low ESR input capacitor is required. A
ceramic capacitor of at least 10µF, placed as close to the VIN
and AGND pins of the device is recommended. The output
capacitor determines the output ripple and the transient
response.
Capacitor
Value
10µF
Vendor
Part Number
Taiyo Yuden
JMK212BJ106MG
TDK
C2012X5ROJ106K
Murata
GRM32ER61C106K
JMK316BJ106KL
C3216X5ROJ106M
Table 2: Recommended Capacitors
PCB Layout Recommendations
The inherently high peak currents and switching frequency of
power supplies require a careful PCB layout design. Therefore,
use wide traces for high current paths and place the input
capacitor, the inductor, and the output capacitor as close as
possible to the integrated circuit terminals. In order to minimize
voltage stress to the device resulting from ever present switching spikes, use an input bypass capacitor with low ESR. Use of
an external Schottky diode with its anode connected to SW
node and cathode connected to PVIN further reduces switching
spikes. Note that the peak amplitude of the switching spikes
depends upon the load current; the higher the load current, the
higher the switching spikes.
The resistor divider that sets the output voltage should be
routed away from the inductor to avoid RF coupling. The ground
FAN2011/FAN2012 Rev. 1.0.2
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FAN2011/FAN2012 1.5A Low Voltage Current Mode Synchronous PWM Buck Regulator
plane at the bottom side of the PCB acts as an electromagnetic
shield to reduce EMI. The recommended PCB layout is shown
below in Figure 5.
FAN2011/FAN2012 1.5A Low Voltage Current Mode Synchronous PWM Buck Regulator
Mechanical Dimensions
3x3mm 6-Lead MLP
Ordering Information
Product Number
Output Voltage
Package Type
Ambient Operating
Temperature
Order Code
FAN2011
Adjustable
3x3mm 6-Lead MLP
0°C to 85°C
FAN2011MPX
FAN2012
Adjustable
3x3mm 6-Lead MLP
0°C to 85°C
FAN2012MPX
FAN2011I
Adjustable
3x3mm 6-Lead MLP
-40°C to 85°C
FAN2011IMPX
FAN2012I
Adjustable
3x3mm 6-Lead MLP
-40°C to 85°C
FAN2012IMPX
FAN2011/FAN2012 Rev. 1.0.2
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support device or system whose failure to perform can
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be reasonably expected to cause the failure of the life
the body, or (b) support or sustain life, or (c) whose
support device or system, or to affect its safety or
failure to perform when properly used in accordance
with instructions for use provided in the labeling, can be
effectiveness.
reasonably expected to result in significant injury to the
user.
PRODUCT STATUS DEFINITIONS
Definition of Terms
Datasheet Identification
Product Status
Definition
Advance Information
Formative or
In Design
This datasheet contains the design specifications for
product development. Specifications may change in
any manner without notice.
Preliminary
First Production
This datasheet contains preliminary data, and
supplementary data will be published at a later date.
Fairchild Semiconductor reserves the right to make
changes at any time without notice in order to improve
design.
No Identification Needed
Full Production
This datasheet contains final specifications. Fairchild
Semiconductor reserves the right to make changes at
any time without notice in order to improve design.
Obsolete
Not In Production
This datasheet contains specifications on a product
that has been discontinued by Fairchild semiconductor.
The datasheet is printed for reference information only.
Rev. I14
FAN2011/FAN2012 Rev. 1.0.2
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FAN2011/FAN2012 1.5A Low Voltage Current Mode Synchronous PWM Buck Regulator
TRADEMARKS