ANALOG DEVICES ADP1614 Service Manual

PWM, DC-to-DC Switching Converter

ADP1614

Rev. 0

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ADP1614

8

3

9

10

6

2

1

VIN

EN

CLRES

SS

SW

7

SW

FB

COMP

ON

OFF

5

GND

4

GND

11

EP

V

OUT

V

IN

L1

C

IN

C

SS

C

OUT

C

COMP

R

COMP

R

CL

R1

R2

D1

10293-001

Data Sheet

FEATURES

Adjustable current limit, up to 4 A

2.5 V to 5.5 V input voltage range
650 kHz or 1.3 MHz fixed frequency option
Adjustable output voltage, up to 20 V
Adjustable soft start
Undervoltage lockout
Thermal shutdown
3 mm × 3 mm, 10-lead LFCSP
Supported by ADIsimPower design tool

650 kHz/1.3 MHz, 4 A, Step-Up,

TYPICAL APPLICATIONS CIRCUIT

APPLICATIONS

TFT LCD bias supplies
Portable applications
Industrial/instrumentation equipment

GENERAL DESCRIPTION

The ADP1614 is a step-up, dc-to-dc switching converter with
an integrated power switch capable of providing an output
voltage as high as 20 V. The ADP1614 is available with a pin­adjustable current limit that is set via an external resistor. The
boost switching frequency is fixed to either 650 kHz or 1.3 MHz.
With a package height of 0.8 mm, the ADP1614 is optimal for
space constrained applications, such as portable devices or thin
film transistor (TFT) liquid crystal displays (LCDs).

The ADP1614 operates in current-mode pulse-width modulation
(PWM) with up to 94% efficiency. Adjustable soft start prevents
inrush currents when the part is enabled. The PWM current-mode
architecture allows excellent transient response, easy noise filtering,
and the use of small, cost-saving external inductors and capacitors.
Other key features include undervoltage lockout (UVLO), thermal
shutdown (TSD), and logic controlled enable.

The ADP1614 is available in a Pb-free, 10-lead lead frame chip
scale package (LFCSP).

Figure 1. Step-Up Regulator Configuration

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ADP1614 Data Sheet

TABLE OF CONTENTS

Features .............................................................................................. 1

Applications ....................................................................................... 1

General Description ......................................................................... 1

Typical Applications Circuit ............................................................ 1

Revision History ............................................................................... 2

Specifications ..................................................................................... 3

Absolute Maximum Ratings ............................................................ 4

Thermal Resistance ...................................................................... 4

ESD Caution .................................................................................. 4

Pin Configuration and Function Descriptions ............................. 5

Typical Performance Characteristics ............................................. 6

Theory of Operation ...................................................................... 10

Current-Mode PWM Operation .............................................. 11

Adjustable Current Limit .......................................................... 11

Frequency Selection ................................................................... 11

Soft Start ...................................................................................... 11

Thermal Shutdown (TSD) ........................................................ 11

Undervoltage Lockout (UVLO) ............................................... 11

Shutdown Mode ......................................................................... 11

Applications Information .............................................................. 12

ADIsimPower Design Tool ....................................................... 12

Setting the Output Voltage ........................................................ 12

Inductor Selection ...................................................................... 12

Choosing the Input and Output Capacitors ........................... 13

Diode Selection ........................................................................... 13

Loop Compensation .................................................................. 13

Soft Start Capacitor .................................................................... 14

PCB Layout Guidelines .................................................................. 15

Outline Dimensions ....................................................................... 16

Ordering Guide .......................................................................... 16

REVISION HISTORY

6/12—Revision 0: Initial Version

Rev. 0 | Page 2 of 16

Data Sheet ADP1614

Peak Current Limit2

RCL = 154 kΩ, duty cycle = 70%

0.95

1.3

1.65

A

ADP1614ACPZ-650-R7

500

650

720

kHz

THERMAL SHUTDOWN

SPECIFICATIONS

VIN = 3.6 V, unless otherwise noted. Minimum and maximum values are guaranteed for TJ = −40°C to +125°C. Typical values specified
are at T
control (SQC), unless otherwise noted.

Table 1.

Parameter Symbol Test Conditions/Comments Min Typ Max Unit

SUPPLY

UNDERVOLTAGE LOCKOUT (UVLO)

OUTPUT

REFERENCE

ERROR AMPLIFIER

SWITCH (SW)

= 25°C. All limits at temperature extremes are guaranteed by correlation and characterization using standard statistical quality

J

Input Voltage VIN 2.5 5.5 V
Quiescent Current

Shutdown I

VEN = 0 V 0.25 1.5 µA

QSHDN

Nonswitching State IQ VFB = 1.3 V, fSW = 1.3 MHz and 650 kHz 700 1100 µA
Switching State1 I

fSW = 1.3 MHz, no load 5.5 7 mA

QSW

fSW = 650 kHz, no load 3 4.5 mA
Enable Pin Bias Current IEN VEN = 3.6 V 3.4 7 µA

Undervoltage Lockout Threshold VIN rising 2.33 2.5 V
VIN falling 2.0 2.20 V

Output Voltage V
Load Regulation V

VIN 20 V

OUT

= 10 V, I

OUT

= 1 mA to 1 A 0.005 mV/mA

LOAD

Feedback Voltage VFB −1.6% 1.245 +1.6% V
Line Regulation VIN = 2.5 V to 5.5 V 0.02 0.2 %/V

Transconductance G

MEA

ΔI = 4 µA 150 µA/V
Voltage Gain AV 80 dB
FB Pin Bias Current VFB = 1.245 V 1 50 nA

On Resistance R

ISW = 1.0 A 50 100 mΩ

DSON

Leakage Current VSW = 20 V 0.1 10 µA

Maximum Peak Current Limit3 RCL = 61.9 kΩ, VIN = 3.6 V, V

CLRES VOLTAGE4 I
I

= 5 µA 1.225 1.27 1.315 V

CLRES

= 20 µA 1.18 1.22 1.25 V

CLRES

= 15 V 4 A

OUT

OSCILLATOR

Oscillator Frequency fSW ADP1614ACPZ-1.3-R7 1.1 1.3 1.4 MHz

Maximum Duty Cycle D

COMP = open, VFB = 1 V, fSW = 1.3 MHz and 650 kHz 88 92 %

MAX

EN LOGIC THRESHOLD VIN = 2.5 V to 5.5 V

Input Voltage Low VIL 0.3 V
Input Voltage High VIH 1.6 V

SOFT START (SS)

Charging Current ISS VSS = 0 V 3.4 5.5 7 µA
Pin Voltage VSS VFB = 1.3 V 1.17 1.23 1.29 V

Thermal Shutdown Threshold 150 °C
Thermal Shutdown Hysteresis 20 °C

1

This parameter specifies the average current when the device switches internally with the SW pins (Pin 6 and Pin 7) floating.

2

Current limit is a function of duty cycle. For the adjustable current limit versions, it is also a function of the resistor on the CLRES pin. See Figure 9 through Figure 12.

3

Guaranteed by design.

4

The CLRES pin cannot be controlled with a current source. An equivalent resistance should be used.

Rev. 0 | Page 3 of 16

ADP1614 Data Sheet

Soldering Conditions

JEDEC J-STD-020

10-Lead LFCSP

47

7.22

°C/W

ABSOLUTE MAXIMUM RATINGS

Table 2.

Parameter Rating

VIN, EN, FB to GND −0.3 V to +6 V
CLRES to GND −0.3 V to VIN
COMP to GND 1.0 V to 1.6 V
SS to GND −0.3 V to +1.3 V
SW to GND 21 V
Operating Junction Temperature Range −40°C to +125°C
Storage Temperature Range −65°C to +150°C

Stresses above those listed under Absolute Maximum Ratings
may cause permanent damage to the device. This is a stress
rating only; 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.

THERMAL RESISTANCE

The junction-to-ambient thermal resistance (θJA) of the package
is specified for the worst-case conditions, that is, a device soldered
in a circuit board for surface-mount packages. The θ

is highly

JA

dependent on the application and board layout. In applications
where high maximum power dissipation exists, attention to
thermal board design is required. The value of θ

may vary,

JA

depending on the printed circuit board (PCB) material, layout,
and environmental conditions.

The boundary conditions for the thermal resistance of the

ADP1614 are modeled under natural convection cooling at

25°C ambient temperature, JESD 51-9, and 1 W power input on a
4-layer board.

Table 3. Thermal Resistance

Package Type θJA θJC Unit

1

Thermal numbers per JEDEC standard JESD 51-9.

1

ESD CAUTION

Rev. 0 | Page 4 of 16

Data Sheet ADP1614

1COMP
2FB
3EN
4GND
5GND

10 SS
9 CLRES
8 VIN
7 SW
6 SW

ADP1614

TOP VIEW

(Not to S cale)

NOTES

1. THE EXPOSED PAD IS NOT ELECTRICALLY
CONNECTED; CONNECT THIS P AD TO A GROUND
PLANE FOR BETTER HEAT DISTRI BUTION.

10293-002

3

EN

Enable Input. Drive EN low to shut down the regulator; drive EN high to turn on the regulator.

PIN CONFIGURATION AND FUNCTION DESCRIPTIONS

Figure 2. Pin Configuration

Table 4. Pin Function Descriptions

Pin No. Mnemonic Description

1 COMP Compensation Input. Connect a series resistor-capacitor network from COMP to GND to compensate the regulator.
2 FB Output Voltage Feedback Input. Connect a resistive voltage divider from the output voltage to FB to set the

regulator output voltage.

4, 5 GND Ground.
6, 7 SW Switching Output. Connect the power inductor from the input voltage to SW and connect the external rectifier

from SW to the output voltage to complete the step-up converter.

8 VIN Main Power Supply Input. VIN powers the ADP1614 internal circuitry. Connect VIN to the input source voltage.

Bypass VIN to GND with a 10 µF or greater capacitor as close to the ADP1614 as possible.
9 CLRES Connect a resistor to GND to set the peak inductor current.
10 SS Soft Start. A capacitor connected from SS to GND brings up the output slowly at power-up and reduces inrush

current.
11 EP Exposed Die Attach Pad. The exposed pad is not electrically connected; connect this pad to a ground plane for

better heat distribution.

Rev. 0 | Page 5 of 16