Diodes PAM2316 User Manual

A

f

Product Line o

Diodes Incorporated

PAM2316

2.5MHz, FAST TRANSIENT 2A STEP-DOWN CONVERTER

Description

The PAM2316 is a 2A step-down sync converter. The 2.5MHz

switching frequency enables the use of small external components.

The ultra-small 2mm x 2mm footprint and high efficiency make the

PAM2316 an ideal choice for portable applications.

The PAM2316 delivers A maximum output current while consuming

only 55µA no load quiescent current. Low R

MOSFETs and 100 duty cycle operation make the PAM2316 the ideal

choice for high output voltage, high current applications which require

a low dropout threshold.

The PAM2316 provides excellent transient response and output

accuracy across the operating range.

The PAM2316 maintains high efficiency throughout the load range.

The PAM2316 automatically optimizes efficiency during light load

mode (PSM) and maintains constant frequency and low output ripple

during PWM mode.

Over-temperature and short circuit protection safeguard the PAM2316

and system components from damage.

The PAM2316 is available in a Pb-free, ultrasmall, low profile, 8-pin

2mmx2mm TDFN package. The product is rated over a temperature

range of -40°C to +85°C.

DS(ON)

integrated

Features

 2A Maximum Output Current
 Tiny 1.0µH Chip Inductor
 Excellent Transient Response
 Input Voltage: 2.7V to 5.5V
 Ultra-small, Low Profile 8-pin 2mmx2mm TDFN Package
 Fixed or Adjustable Output Voltage

- Adjustable Output Voltage: 1.0V to 3.3V

 High Efficiency with 2.5MHz Switching Frequency
 55µA No Load Quiescent Current
 100% Duty Cycle Low-Dropout Operation
 Internal Soft Start
 Over-Temperature and Current Limit Protection
 <1µA Shutdown Current
 -40°C to +85°C Temperature Range
 Pb-Free/Halogen Free Package
 RoHS/REACH Compliant

PAM2316

Document number: DSxxxxx Rev. 1 - 1

Pin Assignments

Applications

 Cellular Phone
 Digital Cameras
 Hard Disk Drives
 MP3 Players
 PDAs and Handheld Computers
 Portable Media Players
 USB Devices
 Wireless Network Cards

1 of 11

www.diodes.com

November 2012

© Diodes Incorporated

A

f

Typical Applications Circuit

Pin Descriptions

Pin

Number

1 PGND
2 PVIN
3 VIN
4 FB
5 AGND

6 EN

7, 8 SW

Pin

Name

Main power ground return pin. Connect to the output and input capacitor return.

Input power supply tied to the source of the high side P-channel MOSFET.

Power supply; supplies power for the internal circuitry.

Feedback input pin. Feedback voltage to internal error amplifier, the threshold voltage is 0.6V.

Analog ground. This pin is internally connected to the analog ground of the control circuitry.
Enable pin. A logic low disables the converter and it consumes less than 1μA of current.When connected high, it

resumes normal operation.
Switching node. Connect the inductor to this pin. It is internally connected to the drain of both high and low side
MOSFETs.

Functional Block Diagram

V

= 0.6* (1+R1/R2)

OUT

Product Line o

Diodes Incorporated

PAM2316

Function

PAM2316

Document number: DSxxxxx Rev. 1 - 1

2 of 11

www.diodes.com

November 2012

© Diodes Incorporated

A

f

Product Line o

Diodes Incorporated

PAM2316

Absolute Maximum Ratings (@T

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 +6.5 V

EN, FB Pin Voltage

SW Pin Voltage

Junction Temperature 150 °C

Storage Temperature Range -65 to +150 °C

Soldering Temperature 300, 5sec °C

Recommended Operating Conditions (@T

Parameter Rating Unit

Supply Voltage 2.7 to 5.5 V

Operation Temperature Range -40 to +85

Junction Temperature Range -40 to +125

= +25°C, unless otherwise specified.)

A

-0.3 to V

-0.3 to (V

+0.3)

IN

IN

= +25°C, unless otherwise specified.)

A

V

V

°C

Thermal Information

Parameter Package Symbol Max Unit

Thermal Resistance (Junction to Case) TDFN22-8

Thermal Resistance (Junction to Ambient) TDFN22-8

Internal Power Dissipation TDFN22-8

PAM2316

Document number: DSxxxxx Rev. 1 - 1

www.diodes.com

θ

θ

P

3 of 11

JC

JA

D

23.4

70

1.4 W

°C/W

November 2012

© Diodes Incorporated

A

f

Product Line o

Diodes Incorporated

PAM2316

Electrical Characteristics (@T

Parameter Symbol Test Conditions Min Typ Max Units

Input Voltage Range

UVLO Threshold

Output Voltage Range

Output Voltage Accuracy

Regulated Feedback Voltage

PMOS Current Limit

Output Voltage Line Regulation LNR

Output Voltage Load Regulation LDR

Quiescent Current

Shutdown Current

Oscillator Frequency

Drain-Source On-State Resisitance

SW Leakage Current ILSW 1 µA

Start-Up Time

PSM Threshold

EN Threshold High

EN Threshold Low

EN Leakage Current

Over Temperature Protection OTP 150 °C

OTP Hysteresis OTH 30 °C

PAM2316

Document number: DSxxxxx Rev. 1 - 1

= +25°C, VIN = 3.3V, V

A

IN

V

Rising

IN

Hysteresis 250 mV

V

V

UVLO

VIN Falling

V

V

V

I

f

R

DS(ON)

V

V

OUT

OUT

LIM

I

I

SD

OSC

T

I

TH

I

EN

IO = 0 to 2A

No Load 0.591 0.600 0.609 V

FB

V

= 3.3V to 4V

IN

I

= 1mA to 2A

O

No Load 55 90 µA

Q

VEN = 0V

IDS = 100mA

250 µs

S

VIN = 3.3V, VO = 1.2V

V

EH

1.4 0.4 V

EL

±0.01 µA

www.diodes.com

= 1.2V, CIN = 10µF, CO = 10µF, L = 1µH, unless otherwise specified.)

OUT

2.7 3.3 5.5 V

2.6 2.7 V

2 V

1 1.2 3.3 V

-3.0 +3.0 %

3.0 A

0.3 %/V

-2 +2 %

1 µA

2.5 MHz

P MOSFET 105 mΩ

N MOSFET 70 mΩ

250 450 mA

4 of 11

November 2012

© Diodes Incorporated

A

f

Typical Performance Characteristics (@T

Product Line o

Diodes Incorporated

= +25°C, CIN = 22*2µF, CO = 22µF, unless otherwise specified.)

A

PAM2316

PAM2316

Document number: DSxxxxx Rev. 1 - 1

5 of 11

www.diodes.com

November 2012

© Diodes Incorporated

A

f

Typical Performance Characteristics (cont.) (@T

Product Line o

Diodes Incorporated

PAM2316

= +25°C, CIN = 22*2µF, CO = 22µF, unless otherwise specified.)

A

PAM2316

Document number: DSxxxxx Rev. 1 - 1

6 of 11

www.diodes.com

November 2012

© Diodes Incorporated

A

f

Product Line o

Diodes Incorporated

PAM2316

Application Information

The basic PAM2316 application circuit is shown on Page 2. External component selection is determined by the load requirement, selecting L first

and then C

Inductor Selection

For most applications, the value of the inductor will fall in the range of 0.47μH to 2μH. 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 V

current as shown in equation 2.0A reasonable starting point for setting ripple current is ∆I

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 2.8A rated inductor should be enough for most applications (2A + 800mA). For better efficiency, choose a low DC-resistance inductor.

CIN and C

In continuous mode, the source current of the top MOSFET is a square wave of duty cycle V

ESR input capacitor sized for the maximum RMS current must be used. The maximum RMS capacitor current is given by:

This formula has a maximum at V

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 C

Typically, once the ESR requirement for C

output ripple V

Where f = operating frequency, C

highest at maximum input voltage since ∆I

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.

Thermal Consideration

Thermal protection limits power dissipation in the PAM2316. When the junction temperature exceeds +150°C, the OTP (Over Temperature

Protection) starts the thermal shutdown and turns the pass transistor off. The pass transistor resumes operation after the junction temperature

drops below +120°C.

For continuous operation, the junction temperature should be maintained below +125°C. The power dissipation is defined as:

I

is the step-down converter quiescent current. The term tsw is used to estimate the full load step-down converter switching losses.

Q

For the condition where the step-down converter is in dropout at 100% duty cycle, the total device dissipation reduces to:

PAM2316

Document number: DSxxxxx Rev. 1 - 1

and C

IN



I

OUT

C

IN



.

OUT

1



Lf






1

V

OUTL






V

OUT



Equation (1)



V

IN



Selection







required

is determined by:

OUT



2



IP

OD

2

OD



II

OMAXRMS

= 2V

IN







IV

LOUT

OUT



VIRIP

, where I

OUT

OUT

f8/1ESR

C

OUT

= output capacitance and ∆IL = ripple current in the inductor. For a fixed output voltage, the output ripple is

increases with input voltage.

L





V

IN

INQH)ON(DS

VVV

V

IN

RMS

has been met, the RMS current rating generally far exceeds the I

RVVRV

2/1

OUTINOUT

=I

/2. This simple worst –case condition is commonly used for design because even

OUT

is driven by the required effective series resistance (ESR).

OUT

L)ON(DSOINH)ON(DSO



t

SW



VIIF

INQOS

7 of 11

www.diodes.com

= 800mA (40% of 2A).

L

. To prevent large voltage transients, a low

OUT/VIN

IN

or V

also increases the ripple

OUT

(P-P) requirement. The

RIPPLE

November 2012

© Diodes Incorporated

A

f

Product Line o

Diodes Incorporated

PAM2316

Application Information (cont.)

Since R

voltage range. The maximum power dissipation depends on the thermal resistance of IC package, PCB layout, the rate of surrounding airflow

and temperature difference between junction and ambient. The maximum power dissipation can be calculated by the following formula:

Where T

junction to the ambient. Based on the standard JEDEC for a two layers thermal test board, the thermal resistance θ

respectively. The maximum power dissipation at T

P

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.

Pulse Skipping Mode (PSM) Description

When load current decreases, the peak switch current in Power-PMOS will be lower than skip current threshold and the device will enter into

Pulse Skipping Mode.

In this mode, the device has two states, working state and idle state. First, the device enters into working state control led by internal error

amplifier. When the feedback voltage gets higher than internal reference voltage, the device will enter into low I

blocks disabled. The output voltage will be reduced by loading or leakage current. When the feedback voltage gets lower than the internal

reference voltage, the convertor will start a working state again.

100% Duty Cycle Operation

As the inpput 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:

where R

UVLO and Soft-Start

The reference and the circuit remain reset until the VIN crosses its UVLO threshold.

The PAM2316 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.

, quiescent current, and switching losses all vary with input voltage, the total losses should be investigated over the complete input

DS(ON)



TT

A)MAX(J



P

D

J(MAX)

= (125°C - 25°C) /70°C/W = 1.42W

D

V

O

V

O

1.2V 150k 150k

1.5V 150k 100k

1.8V 300k 150k

2.5V 380k 120k

3.3V 680k 150k

DS(ON)



is the maximum allowable junction temperature +125°C. TA is the ambient temperature and θJA is the thermal resistance from the



1x6.0




= P-Channel Switch ON resistance, I

JA

= +25°C can be calculated by following formula:

A

1R







2R



R1 R2





RRIVV

LDSONLOADINOUT

= Output Current, RL = Inductor DC Resistance

LOAD

of TDFN2X2 70°C/W,

JA

idle state with most of internal

Q

PAM2316

Document number: DSxxxxx Rev. 1 - 1

8 of 11

www.diodes.com

November 2012

© Diodes Incorporated

A

f

Product Line o

Diodes Incorporated

PAM2316

Application Information (cont.)

Short Circuit Protection

When the converter output is shorted or the device is overloaded, each high-side MOSFET current-limit event (3A typ) turns off the high-side

MOSFET and turns on the low-side MOSFET. An internal counter is used to count the each current-limit event. The counter is reset after

consecutive high-side MOSFETs turn on without reaching cur rent l imi t. I f the current- limit condition persists, the counter fills up. The control

logic then stops both high-side and lowside MOSFETs and waits for a hiccup period, before attemping a new soft-start sequence. The counter

bits is decided by V

cycle is 1.7%. The hicuup mode is disable during soft-start time.

voltage. If VFB ≤ 0 2, the counter is 3-bit counter; if VFB > 0.2 the counter is 6-bit counter. The typical hicuup made duty

FB

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 PAM2316. Check the following
in your layout:

1. The input capacitor should be close to IC as close as possible.

2. Must put a small decoupling capacitor between V

3. Minimize the switching loop area to avoid excessive switching noise.

4. AGND and PGND should connect at input capacitor GND.

5. For the good thermal dissipation, PAM2316 has a heat dissipate pad in the bottom side, it should be soldered to PCB surface. For the copper

area can't be large in the component side, so we can use mu ltiple vias connect to other side of the PCB.

Pin and AGND Pin.

IN

Ordering Information

Part Number Output Voltage Part Type Standard Package

PAM2316AGCADJ CHVYW T-DFN22-8 3000 Units/Tape & Reel

Marking Information

PAM2316

Document number: DSxxxxx Rev. 1 - 1

www.diodes.com

9 of 11

November 2012

© Diodes Incorporated

A

f

Package Outline Dimensions (All dimensions in mm.)

Product Line o

Diodes Incorporated

PAM2316

PAM2316

Document number: DSxxxxx Rev. 1 - 1

www.diodes.com

10 of 11

November 2012

© Diodes Incorporated

A

f

Product Line o

Diodes Incorporated

PAM2316

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.

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 © 2012, Diodes Incorporated

www.diodes.com

IMPORTANT NOTICE

LIFE SUPPORT

PAM2316

Document number: DSxxxxx Rev. 1 - 1

11 of 11

www.diodes.com

November 2012

© Diodes Incorporated