Fairchild FAN2011, FAN2012 service manual
FAN2011/FAN2012 1.5A Low Voltage Current Mode Synchronous PWM Buck Regulator
April 2006
FAN2011/FAN2012
1.5A Low Voltage Current Mode Synchronous PWM Buck
Regulator
Features
95% Efficiency, Synchronous Operation
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■
Adjustable Output Voltage from 0.8V to V
4.5V to 5.5V Input Voltage Range
■
■
Up to 1.5A Output Current
Fixed Frequency 1.3 MHz PWM Operation
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■
100% Duty Cycle Low Dropout Operation (LDO)
Soft Start
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■
Excellent Load Transient Response
3x3mm 6-lead MLP Package
■
IN
Applications
Hard Disk Drive
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■
Set T op Box
Point of Load Power
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Notebook Computers
Communications Equipment
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Description
The FAN2011/FAN2012 is a high-efficiency, low-noise
synchronous Pulse Width Modulated (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 V
external voltage divider.
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.
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 av ailab le 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.
by means of an
IN
Ordering Information
Product Number Output Voltage Package Type
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 FAN2011EMPX
FAN2012I Adjustable 3x3mm 6-Lead MLP -40°C to 85°C FAN2012EMPX
FAN2011/FAN2012 Rev. 1.0.4
©2006 Fairchild Semiconductor Corporation
Ambient Operating
Temperature Order Code
1
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Typical Application
FAN2011/FAN2012 1.5A Low Voltage Current Mode Synchronous PWM Buck Regulator
10KΩ
V
OUT
R2
R1
4 x 10µF
PGND
L1
3.3µH
Pin Assignment
SW
FB
1
P1
2
(A
3
GND)
6
NC
V
5
PV
4
+5V
IN
V
IN
10µF
OUT
R2
R1
4 x 10µF
10KΩ
L1
3.3µH
FB
PGND
SW
FAN2011 FAN2012
Figure 1. Typical Application
Top View
1
FB
P1
2
PGND
SW
(AGND)
3
FAN2011
3x3mm 6-Lead MLP
6
NC
V
5
IN
4
PV
IN
1
FB
P1
2
PGND
SW
(AGND)
3
FAN2012
3x3mm 6-Lead MLP
EN
6
V
5
IN
4
PV
IN
Figure 2. Pin Assignment
1
P1
2
(A
GND)
3
EN
6
V
5
PV
4
+5V
IN
IN
10µF
Pin Description
FAN2011 (3x3mm 6-Lead MLP)
Pin No. Pin Name Pin Description
P1 AGND
1FB
2 PGND
3SW
4 PV
5V
IN
IN
6NC
FAN2012 (3x3mm 6-Lead MLP)
Pin No. Pin Name Pin Description
P1 AGND
1 FB
2 PGND
3SW
4PV
5V
6EN
IN
IN
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.
Switching Node. This pin is connected to the internal MOSFET switches.
Supply V oltage Input. This pin is connected to the internal MOSFET switches.
Supply V oltage Input.
Not Connected. This pin is not internally connected.
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.
Switching Node. This pin is connected to the internal MOSFET switches.
Supply V oltage Input. This pin is connected to the internal MOSFET switches.
Supply V oltage Input.
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. 1.0.4
2
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µ
µ
Absolute Maximum Ratings
Stresses above those listed under “Absolute Maxim um 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.
Parameter Min. Max. Unit
V
IN
PV
and any other pin -0.3 V
IN
Thermal Resistance-Junction to Tab ( θ
), 3mm x 3mm 6-lead MLP
JC
(1)
Lead Soldering Temperature (10 seconds) – 260 °C
Storage Temperature -65 150 °C
Junction Temperature -40 150 °C
Electrostatic Discharge (ESD) Protection Level
(2)
HBM 4 – kV
CDM 2 –
-0.3 7 V
IN
–8°C/W
V
FAN2011/FAN2012 1.5A Low Voltage Current Mode Synchronous PWM Buck Regulator
Recommended Operating Conditions
Parameter Min. Typ. Max. Unit
Supply Voltage Range 4.5 – 5.5 V
Output Voltage Range, Adjustable Version 0.8 – V
Output Current – – 1500 mA
Inductor
Input Capacitor
Output Capacitor
Operating Ambient Temperature
Range
(3)
(3)
(3)
– 3.3 –
–10– µ F
–4 x 10 –
FAN2011 and FAN2012 0 – +85 °C
FAN2011I and FAN2012I -40 – +85
Notes:
1. Junction to ambient thermal resistance, θ
, is a strong function of PCB material, board thickness, thickness and
JA
number of copper planes, number of via used, diameter of via used, available copper surface, and attached heat sink
characteristics.
2. Using Mil Std. 883E, method 3015.7(Human Body Model) and EIA/JESD22C101-A (Charge Device Model).
3. Refer to the applications section for further details.
IN
V
H
F
FAN2011/FAN2012 Rev. 1.0.4
3
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