PAM2301
Document number: DS36384 Rev. 3 - 2
1 of 13
www.diodes.com
February 2018
© Diodes Incorporated
PAM2301
NEW PROD UCT
800mA STEP-DOWN DC-DC CONVERTER
Description
The PAM2301 is a step-down current-mode, DC-DC converter. At
heavy load, the constant frequency PWM control performs excellent
stability and transient response. To ensure the longest battery life in
portable applications, the PAM2301 provides a power-saving Pulse-
Skipping Modulation (PSM) mode to reduce quiescent current under
light load operation to save power.
The PAM2301 supports a range of input voltages from 2.5V to 5.5V,
allowing the use of a single Li+/Li-polymer cell, multiple Alkaline/NiMH
cell, USB and other standard power sources. The output voltage is
adjustable from 0.6V to the input voltage, while the part number suffix
PAM2301-XX indicates pre-set output voltage of 3.3V, 1.2V or
adjustable. All versions employ internal power switch and
synchronous rectifier to minimize external part count and realize high
efficiency. During shutdown, the input is disconnected from the output
and the shutdown current is less than 0.1mA. Other key features
include under-voltage lockout to prevent deep battery discharge.
The PAM2301 is available in TSOT25 package.
Features
Efficiency up to 96%
Only 40μA (typ) Quiescent Current
Output Current: Up to 800mA
Internal Synchronous Rectifier
1.5MHz Switching Frequency
Soft Start
Under-Voltage Lockout
Short Circuit Protection
Thermal Shutdown
TSOT25 Package
Totally Lead-Free & Fully RoHS Compliant (Notes 1 & 2)
Halogen and Antimony Free. “Green” Device (Note 3)
Pin Assignments
Applications
Cellular Phone
Portable Electronics
Wireless Devices
Cordless Phone
Computer Peripherals
Battery-Powered Widgets
Electronic Scales
Digital Frame
Notes: 1. No purposely added lead. Fully EU Directive 2002/95/EC (RoHS), 2011/65/EU (RoHS 2) & 2015/863/EU (RoHS 3) compliant.
2. See https://www.diodes.com/quality/lead-free/ for more information about Diodes Incorporated’s definitions of Halogen- and Antimony-free, "Green"
and Lead-free.
3. Halogen- and Antimony-free "Green” products are defined as those which contain <900ppm bromine, <900ppm chlorine (<1500ppm total Br + Cl) and
<1000ppm antimony compounds.
TSOT25
PAM2301
Document number: DS36384 Rev. 3 - 2
2 of 13
www.diodes.com
February 2018
© Diodes Incorporated
PAM2301
NEW PROD UCT
Typical Applications Circuit
Fixed Output Voltage
Adjustable Output Voltage
2R1R
16.0
VO
Pin Descriptions
Pin Number
Pin Name
Function
1
EN
Enable Control Input. Force this pin voltage above 1.5V, enables the chip, and below 0.3V shuts down the device.
2
GND
Ground
3
SW
The drains of the internal main and synchronous power MOSFET.
4
VIN
Power Supply
5
VOUT/FB
VOUT: Output voltage feedback pin, an internal resistive divider divides the
output voltage down for comparison to the internal reference voltage.
FB: Feedback voltage to internal error amplifier, the threshold voltage is 0.6V.
Functional Block Diagram
PAM2301
Document number: DS36384 Rev. 3 - 2
3 of 13
www.diodes.com
February 2018
© Diodes Incorporated
PAM2301
NEW PROD UCT
Absolute Maximum Ratings (@TA = +25°C, unless otherwise specified.)
These are stress ratings only and functional operation is not implied. Exposure to absolute maximum ratings for prolonged time periods may affect device reliability.
All voltages are with respect to ground.
Parameter
Rating
Unit
Input Voltage
-0.3 to +6.0
V
EN, FB Pin Voltage
-0.3 to VIN
V
SW Pin Voltage
-0.3 to (VIN + 0.3)
V
Junction Temperature
+150
°C
Storage Temperature Range
-65 to +150
°C
Soldering Temperature
+300, 5s
°C
Recommended Operating Conditions (@TA = +25°C, unless otherwise specified.)
Parameter
Rating
Unit
Supply Voltage
2.5 to 5.5
V
Operation Temperature Range
-40 to +85
°C
Juntion Temperature Range
-40 to +125
Thermal Information
Parameter
Symbol
Max
Unit
Thermal Resistance (Junction to Case)
θJC
130
°C/W
Thermal Resistance (Junction to Ambient)
θJC
250
Internal Power Dissipation
PD
400
mW
Electrical Characteristics (@TA = +25°C, VIN = 3.6V, VO = 1.8V, CIN = 10µF, L = 4.7µH unless otherwise specified.)
Parameter
Symbol
Test Conditions
Min
Typ
Max
Units
Input Voltage Range
VIN
-
2.5
-
5.5
V
Regulated Feedback Voltage
VFB
-
0.588
0.600
0.612
V
Reference Voltage Line Regulation
ΔVFB
-
-
0.3
-
%/V
Regulated Output Voltage Accuracy
VO
IO = 100mA
-3
-
+3
%
Peak Inductor Current
IPK
VIN = 3V,VFB = 0.5V or VO = 90%
-
1.2
-
A
Output Voltage Line Regulation
LNR
VIN = 2.5V to 5V, IO = 10mA
-
0.2
0.5
%/V
Output Voltage Load Regulation
LDR
IO = 1mA to 800mA
-
0.5
1.5
%
Quiescent Current
IQ
No Load
-
40
70
µA
Shutdown Current
ISD
VEN = 0V
-
0.1
1.0
µA
Oscillator Frequency
fOSC
VO = 100%
1.2
1.5
1.8
MHz
VFB = 0V or VO = 0V
-
500
-
kHz
Drain-Source On-State Resistance
RDS(ON)
IDS = 100mA
P MOSFET
-
0.30
0.45
Ω
N MOSFET
-
0.35
0.50
Ω
SW Leakage Current
ILSW
-
-
±0.01
1
µA
High Efficiency
η
-
-
96
-
%
EN Threshold High
VEH
-
1.5
-
-
V
EN Threshold Low
VEL
-
-
-
0.3
V
EN Leakage Current
IEN
-
-
±0.01
-
µA
Over Temperature Protection
OTP
-
-
+150
-
°C
OTP Hysteresis
OTH
-
-
+30
-
°C
PAM2301
Document number: DS36384 Rev. 3 - 2
9 of 13
www.diodes.com
February 2018
© Diodes Incorporated
PAM2301
NEW PROD UCT
Application Information
The basic PAM2301 application circuit is shown on Page 1. External component selection is determined by the load requirement, selecting L first
and then CIN and COUT.
Inductor Selection
For most applications, the value of the inductor will fall in the range of 1μH to 4.7μH. Its value is chosen based on the desired ripple current.
Large value inductors lower ripple current and small value inductors result in higher ripple currents. Higher VIN or VOUT also increases the ripple
current as shown in Equation 1. A reasonable starting point for setting ripple current is ΔIL = 320mA (40% of 800mA).
V
V
1
V
Lf1
IIN
OUT
OUTL
Equation 1
The DC current rating of the inductor should be at least equal to the maximum load current plus half the ripple current to prevent core saturation.
Thus, a 1120mA rated inductor should be enough for most applications (800mA + 320mA). For better efficiency, choose a low DC-resistance
inductor.
CIN and COUT Selection
In continuous mode, the source current of the top MOSFET is a square wave of duty cycle VOUT/VIN. To prevent large voltage transients, a low
ESR input capacitor sized for the maximum RMS current must be used. The maximum RMS capacitor current is given by:
VVVV
II
required
CIN
2/1
OUTINOUT
OMAXRMS
IN
This formula has a maximum at VIN = 2VOUT, where IRMS =IOUT/2. This simple worst-case condition is commonly used for design because even
significant deviations do not offer much relief. Note that the capacitor manufacturer's ripple current ratings are often based on 2000 hours of life.
This makes it advisable to further derate the capacitor, or choose a capacitor rated at a higher temperature than required. Consult the
manufacturer if there is any question.
The selection of COUT is driven by the required effective series resistance (ESR).
Typically, once the ESR requirement for COUT has been met, the RMS current rating generally far exceeds the IRIPPLE (P-P) requirement. The
output ripple VOUT is determined by:
fC81
ESR
IV OUT
LOUT
Where f = operating frequency, COUT = output capacitance and ΔIL = ripple current in the inductor. For a fixed output voltage, the output ripple is
highest at maximum input voltage since ΔIL increases with input voltage.
Using Ceramic Input and Output Capacitors
Higher values, lower cost ceramic capacitors are now becoming available in smaller case sizes. Their high ripple current, high voltage rating and
low ESR make them ideal for switching regulator applications. Using ceramic capacitors can achieve very low output ripple and small circuit size.
When choosing the input and output ceramic capacitors, choose the X5R or X7R dielectric formulations. These dielectrics have the best
temperature and voltage characteristics of all the ceramics for a given value and size.
Setting the Output Voltage
The internal reference is 0.6V (Typical). The output voltage is calculated as below:
The output voltage is given by Table 1.
Table 1: Resistor selection for output voltage setting.
VO
R1
R2
1.2V
100k
100k
1.5V
150k
100k
1.8V
200k
100k
2.5V
380k
120k
3.3V
540k
120k
2R1R
16.0
VO
PAM2301
Document number: DS36384 Rev. 3 - 2
10 of 13
www.diodes.com
February 2018
© Diodes Incorporated
PAM2301
NEW PROD UCT
Application Information (Cont.)
100% Duty Cycle Operation
As the input voltage approaches the output voltage, 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 P-Channel transistor:
RRIVV L)ON(DSLOADINOUT
where RDS(ON) = P-Channel Switch ON Resistance, I = Output Current, R = Inductor DC Resistance.
UVLO AND Soft-Start
The reference and the circuit remain reset until the VIN crosses its UVLO threshold.
The PAM2301 has an internal soft-start circuit that limits the in-rush current during start-up. This prevents possible voltage drops of the input
voltage and eliminates the output voltage overshoot. The soft-start acts as a digital circuit to increase the switch current in several steps to the
P-Channel current limit (1500mA).
Short Circuit Protection
The switch peak current is limited cycle-by-cycle to a typical value of 1500mA. 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 200mA.
Thermal Shutdown
When the die temperature exceeds +150°C, a reset occurs and the reset remains until the temperature decrease to 120°C, at which time the
circuit can be restarted.
PCB Layout Check List
When laying out the printed circuit board, the following checklist should be used to ensure proper operation of the PAM2301. These items are
also illustrated graphically in Figure 1. Check the following in your layout:
1. The power traces, consisting of the GND trace, the SW trace and the VIN trace should be kept short, direct and wide.
2. Does the VFB pin connect directly to the feedback resistors? The resistive divider R1/R2 must be connected between the (+) plate of C and
ground.
3. Does the (+) plate of CIN connect to VIN as closely as possible? This capacitor provides the AC current to the internal power MOSFETs.
4. Keep the switching node, SW, away from the sensitive VFB node.
5. Keep the (–) plates of CIN and COUT as close as possible.
Figure 1. PAM2301 Suggested Layout
PAM2301
Document number: DS36384 Rev. 3 - 2
11 of 13
www.diodes.com
February 2018
© Diodes Incorporated
PAM2301
NEW PROD UCT
Ordering Information
PAM2301 X X X X XXX
Pin Configuration B: 5
Number of Pins
Output Current
C: 800mA A: Type
1. EN
2. GND
3. SW
4. VIN
5. VOUT/FB
Package Type
A: TSOT25
Output Voltage
330: 3.3V
280: 2.8V
250: 2.5V
180: 1.8V
150: 1.5V
120: 1.2V
ADJ: Adj
Part Number
Output Voltage
(V)
Part Mark
Package
(Note 5)
7’’ Tape & Reel
Quantity
Status
(Note 4)
PAM2301CAAB330
3.3
BAKYW
TSOT25
3000
In production
PAM2301CAAB120
1.2
BABYW
TSOT25
3000
In production
PAM2301CAABADJ
ADJ
BAAYW
TSOT25
3000
In production
Notes: 4. Variants with output voltage of 1.5V, 1.8V, 2.5V and 2.8V are End of Life with no replacement.
5. For packaging details, go to our website at https://www.diodes.com/design/support/packaging/diodes-packaging/.
Marking Information
TSOT25
PAM2301
Document number: DS36384 Rev. 3 - 2
12 of 13
www.diodes.com
February 2018
© Diodes Incorporated
PAM2301
NEW PROD UCT
Package Outline Dimensions (All dimensions in mm.)
Please see http://www.diodes.com/package-outlines.html for the latest version.
TSOT25
Suggested Pad Layout
Please see http://www.diodes.com/package-outlines.html for the latest version.
TSOT25
Dimensions
Value (in mm)
C
0.950
X
0.700
Y
1.000
Y1
3.199
D
E1
E1/2
e1
E
E/2
e
A
A2
A1
Seating Plane
0
L2
L
Gauge Plane
01(4x)
01(4x)
c
b
Seating Plane
Y1
C
X
Y
TSOT25
Dim
Min
Max
Typ
A
-
1.00
-
A1
0.01
0.10
-
A2
0.84
0.90
-
b
0.30
0.45
-
c
0.12
0.20
-
D
-
-
2.90
E
-
-
2.80
E1
-
-
1.60
e
0.95 BSC
e1
1.90 BSC
L
0.30
0.50
-
L2
0.25 BSC
θ
0°
8°
4°
θ1
4°
12°
-
All Dimensions in mm
PAM2301
Document number: DS36384 Rev. 3 - 2
13 of 13
www.diodes.com
February 2018
© Diodes Incorporated
PAM2301
NEW PROD UCT
IMPORTANT NOTICE
DIODES INCORPORATED MAKES NO WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, WITH REGARDS TO THIS DOCUMENT,
INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
(AND THEIR EQUIVALENTS UNDER THE LAWS OF ANY JURISDICTION).
Diodes Incorporated and its subsidiaries reserve the right to make modifications, enhancements, improvements, corrections or other changes
without further notice to this document and any product described herein. Diodes Incorporated does not assume any liability arising out of the
application or use of this document or any product described herein; neither does Diodes Incorporated convey any license under its patent or
trademark rights, nor the rights of others. Any Customer or user of this document or products described herein in such applications shall assume
all risks of such use and will agree to hold Diodes Incorporated and all the companies whose products are represented on Diodes Incorporated
website, harmless against all damages.
Diodes Incorporated does not warrant or accept any liability whatsoever in respect of any products purchased through unauthorized sales channel.
Should Customers purchase or use Diodes Incorporated products for any unintended or unauthorized application, Customers shall indemnify and
hold Diodes Incorporated and its representatives harmless against all claims, damages, expenses, and attorney fees arising out of, directly or
indirectly, any claim of personal injury or death associated with such unintended or unauthorized application.
Products described herein may be covered by one or more United States, international or foreign patents pending. Product names and markings
noted herein may also be covered by one or more United States, international or foreign trademarks.
This document is written in English but may be translated into multiple languages for reference. Only the English version of this document is the
final and determinative format released by Diodes Incorporated.
LIFE SUPPORT
Diodes Incorporated products are specifically not authorized for use as critical components in life support devices or systems without the express
written approval of the Chief Executive Officer of Diodes Incorporated. As used herein:
A. Life support devices or systems are devices or systems which:
1. are intended to implant into the body, or
2. support or sustain life and whose failure to perform when properly used in accordance with instructions for use provided in the
labeling can be reasonably expected to result in significant injury to the user.
B. A critical component is any component in a life support device or system whose failure to perform can be reasonably expected to cause the
failure of the life support device or to affect its safety or effectiveness.
Customers represent that they have all necessary expertise in the safety and regulatory ramifications of their life support devices or systems, and
acknowledge and agree that they are solely responsible for all legal, regulatory and safety-related requirements concerning their products and any
use of Diodes Incorporated products in such safety-critical, life support devices or systems, notwithstanding any devices- or systems-related
information or support that may be provided by Diodes Incorporated. Further, Customers must fully indemnify Diodes Incorporated and its
representatives against any damages arising out of the use of Diodes Incorporated products in such safety-critical, life support devices or systems.
Copyright © 2018, Diodes Incorporated
www.diodes.com
