2 MHz, Synchronous Boost
DC-to-DC Converter
Data Sheet
ADP1607
Rev. C Document Feedback
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FEATURES
Up to 96% efficiency
0.8 V to VOUT input voltage range
Low 0.9 V input start-up voltage
1.8 V to 3.3 V output voltage range
23 µA quiescent current
Fixed PWM and light load PFM mode options
Synchronous rectification
True shutdown output Isolation
Internal soft start, compensation, and current limit
2 mm × 2 mm, 6-lead LFCSP
Compact solution size
APPLICATIONS
1-cell and 2-cell alkaline and NiMH/NiCd powered devices
Portable audio players, instruments, and medical devices
Solar cell applications
Miniature hard disk power supplies
Power LED status indicators
GENERAL DESCRIPTION
The ADP1607 is a high efficiency, synchronous, fixed
frequency, step-up dc-to-dc switching converter with an
adjustable output voltage between 1.8 V and 3.3 V for use
in portable applications.
The 2 MHz operating frequency enables the use of small
footprint, low profile external components. Additionally, the
synchronous rectification, internal compensation, internal fixed
current limit, and current mode architecture allow for excellent
transient response and a minimal external part count.
Other key features include fixed PWM and light load PFM
mode options, true output isolation, thermal shutdown (TSD),
and logic controlled enable. Available in a lead-free, thin, 6-lead
LFCSP package, the ADP1607 is ideal for providing efficient
power conversion in portable devices.
TYPICAL APPLICATION CIRCUIT
10276-001
ADP1607
1
23
VIN
EN
5
SW
6
VOUT
FB
ON
OFF
4
GND
ADJUSTABLE
OUTPUT VOLTAGE
1.8V TO 3.3V
INPUT VOLTAGE
0.8V TO V
OUT
L
2.2µH
C
IN
10µF
C
OUT
10µF
R1
R2
Figure 1.
ADP1607 Data Sheet
Rev. C | Page 2 of 16
TABLE OF CONTENTS
Features .............................................................................................. 1
Applications ....................................................................................... 1
General Description ......................................................................... 1
Typical Application Circuit ............................................................. 1
Revision History ............................................................................... 2
Specifications ..................................................................................... 3
Absolute Maximum Ratings ............................................................ 4
Thermal Operating Ranges ......................................................... 4
Thermal Resistance ...................................................................... 4
ESD Caution .................................................................................. 4
Pin Configuration and Function Descriptions ............................. 5
Typical Performance Characteristics ............................................. 6
Theory of Operation ...................................................................... 10
Overview ..................................................................................... 10
Enable/Shutdown ....................................................................... 10
Modes of Operation ................................................................... 10
Internal Control Features .......................................................... 11
Applications Information .............................................................. 12
Setting the Output Voltage ........................................................ 12
Inductor Selection ...................................................................... 12
Choosing the Input Capacitor .................................................. 13
Choosing the Output Capacitor ............................................... 13
Layout Guidelines ........................................................................... 14
Outline Dimensions ....................................................................... 15
Ordering Guide .......................................................................... 15
REVISION HISTORY
12/13—Rev. B to Rev. C
Changes to Figure 21 ........................................................................ 9
7/13—Rev. A to Rev. B
Changes to Captions for Figure 22 and Figure 23 ........................ 9
Changed Synchronous Rectification Section .............................. 11
12/12—Rev. 0 to Rev. A
Changes to Features Section............................................................ 1
Changed TJ to TA in Specifications Section ................................... 3
Changed Figure 6, Figure 7, and Figure 8 Captions..................... 6
Changes to Table 5 .......................................................................... 12
Changes to Choosing the Output Capacitor Section ................. 13
10/12—Revision 0: Initial Version
Data Sheet ADP1607
Rev. C | Page 3 of 16
SPECIFICATIONS
VIN = VEN = 1.2 V, VOUT = 3.3 V at TA = −40°C to +85°C for minimum/maximum specifications, and TA = 25°C for typical specifications,
unless otherwise noted.1
Table 1.
Parameter Symbol Test Conditions/Comments Min Typ Max Unit
SUPPLY
Minimum Start-Up Voltage2 RMIN = 22 Ω 0.9 V
Operating Input Voltage Range3 VIN 0.8 VOUT V
Shutdown Current IQSD VEN = GND, VOUT = GND, TA = −40°C to +45°C4 0.06 0.67 µA
Quiescent Current Nonswitching, measured on VOUT, auto
operating mode part only
TA = −40°C to +45°C 23 29 µA
TA = −40°C to +85°C 23 40 µA
Measured on VIN
TA = −40°C to +45°C 6 11 µA
TA = −40°C to +85°C 6 14.6 µA
Soft Start Time
1.3
ms
SWITCH
Current Limit ICL 0.8 1 1.3 A
NMOS On Resistance RDSON_N
ISW = 500 mA 116 165 mΩ
PMOS On Resistance RDSON_P ISW = 500 mA 155 225 mΩ
SW Leakage Current VSW = 1.2 V, VOUT = 0 V, TA = −40°C to +45°C4 0.18 2 µA
OSCILLATOR
Switching Frequency fSW 1.8 2 2.2 MHz
Maximum Duty Cycle DMAX 85 90 %
OUTPUT
VOUT Range VOUT 1.8 3.3 V
FB Pin Voltage VFB PWM mode 1.2338 1.259 1.2842 V
FB Pin Current IFB VFB = 1.26 V 0.1 0.25 µA
EN/MODE LOGIC
Input Voltage Threshold Low VIL 0.25 V
Input Voltage Threshold High VIH 0.8 V
EN/MODE Leakage Current VEN = GND or VIN, VOUT = 0 V 0.001 0.25 µA
THERMAL SHUTDOWN5
Thermal Shutdown Threshold 150 °C
Thermal Shutdown Hysteresis 15 °C
1 All limits at temperature extremes are guaranteed via correlation using standard statistical quality control (SQC). Specifications are subject to change without notice.
2 Guaranteed by design, but not production tested. VIN can never exceed VOUT once the ADP1607 is enabled.
3 Minimum value is characterized by design. Maximum value is characterized on the bench.
4 This parameter is the semiconductor leakage current. The semiconductor leakage current doubles with every 10°C increase in temperature. The maximum limit
follows the same trend over temperature.
5 Thermal shutdown protection is only active in PWM mode.
ADP1607 Data Sheet
Rev. C | Page 4 of 16
ABSOLUTE MAXIMUM RATINGS
Table 2.
Parameter Rating
VIN, VOUT to GND −0.3 V to +3.6 V
FB to GND −0.3 V to +1.4 V
EN, SW to GND (when VIN ≥ VOUT) −0.3 V to VIN + 0.3 V
EN, SW to GND (when VIN < VOUT) −0.3 V to VOUT + 0.3 V
EPAD to GND −0.3 V to + 0.3 V
Operating Ambient Temperature Range −40°C to +85°C
Operating Junction Temperature Range −40°C to +90°C
Storage Temperature Range −65°C to +150°C
Soldering Conditions JEDEC J-STD-020
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 OPERATING RANGES
The ADP1607 can be damaged when the junction temper-
ature limits are exceeded. The maximum operating junction
temperature (TJ(MAX)) takes precedence over the maximum
operating ambient temperature (TA(MAX)). Monitoring ambient
temperature does not guarantee that the junction temperature
(TJ) is within the specified temperature limits.
In applications with high power dissipation and poor PCB
thermal resistance, the maximum ambient temperature may
need to be derated. In applications with moderate power
dissipation and low PCB thermal resistance, the maximum
ambient temperature can exceed the maximum limit as long
as the junction temperature is within specification limits.
The junction temperature TJ of the device is dependent on the
ambient temperature (TA), the power dissipation of the device
(PD), and the junction-to-ambient thermal resistance of the
package (θJA). Maximum junction temperature (TJ) is calculated
from the ambient temperature (TA) and power dissipation (PD)
using the following formula:
TJ = TA + (PD × θJA)
THERMAL RESISTANCE
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
junction-to-ambient thermal resistance is highly 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 θJA may vary, depending on
PCB material, layout, and environmental conditions.
θJA and θJC (junction to case) are determined according to
JESD51-9 on a 4-layer PCB with natural convection cooling
and the exposed pad soldered to the board with thermal vias.
Table 3.
Package Type θJA θJC Unit
6-Lead LFCSP 66.06 4.3 °C/W
ESD CAUTION
Data Sheet ADP1607
Rev. C | Page 5 of 16
PIN CONFIGURATION AND FUNCTION DESCRIPTIONS
10276-002
3FB
1VIN
2EN
4GND
7
EPAD
6VOUT
5SW
ADP1607
TOP VI EW
(Not to Scale)
NOTES
1. CONNECT THE EXPOSED PAD TO GND.
Figure 2. Pin Configuration
Table 4. Pin Function Descriptions
Pin No. Mnemonic Description
1 VIN Analog and Power Supply Pin.
2 EN Shutdown Control Pin. Drive EN high to turn on the synchronous boost, drive EN low to turn it off.
3 FB Output Voltage Feedback Pin.
4 GND Analog and Power Ground Pin.
5 SW Drain Connection for NMOS and PMOS Power Switches.
6 VOUT Output Voltage and Source Connection of PMOS Power Switch.
7 EPAD Exposed Pad. Connect to GND.
ADP1607 Data Sheet
Rev. C | Page 6 of 16
TYPICAL PERFORMANCE CHARACTERISTICS
VIN = 1.2 V, VOUT = 3.3 V, L = 2.2 µH (DCRMAX = 66 mΩ, VLF302512MT-2R2M), CIN = 10 µF, COUT = 10 µF (10 V, 20%,
LMK107BJ106MALT), VEN = VIN, and TA = 25°C, unless otherwise noted.
100
80
60
40
20
90
70
50
30
10
0
0.1 110 100 1000
EF FICIENCY ( %)
LOAD CURRENT ( mA)
V
OUT
= 1.8V
V
IN
= 0.8V
V
IN
= 1.2V
V
IN
= 1.5V
10276-003
Figure 3. Auto Mode Efficiency vs. Load Current, VOUT = 1.8 V
100
80
60
40
20
90
70
50
30
10
0
0.1 110 100 1000
EF FICIENCY ( %)
LOAD CURRENT ( mA)
V
OUT
= 2.5V
VIN = 0.8V
VIN = 1.2V
VIN = 1.5V
VIN = 2.2V
10276-004
Figure 4. Auto Mode Efficiency vs. Load Current, VOUT = 2.5 V
100
80
60
40
20
90
70
50
30
10
0
0.1 110 100 1000
EF FICIENCY ( %)
LOAD CURRENT ( mA)
VOUT = 3. 3V
VIN = 0.8V
VIN = 1.2V
VIN = 1.5V
VIN = 2.2V
VIN = 3.0V
10276-005
Figure 5. Auto Mode Efficiency vs. Load Current, VOUT = 3.3 V
0.1 110 100 1000
OUTPUT VOLTAGE (V)
LOAD CURRENT ( mA)
V
OUT
= 1.8V
1.78
1.79
1.80
1.81
1.82
1.83
1.84 V
IN
= 0.8V
V
IN
= 1.2V
V
IN
= 1.5V
10276-006
Figure 6. Auto Mode Output Voltage Load Regulation, VOUT = 1.8 V
0.1 110 100 1000
OUTPUT VOLTAGE (V)
LOAD CURRENT ( mA)
V
OUT
= 2.5V
2.47
2.48
2.49
2.50
2.51
2.52
2.53
2.54
2.55
2.56 V
IN
= 0.8V
V
IN
= 1.2V
V
IN
= 1.5V
V
IN
= 2.2V
10276-007
Figure 7. Auto Mode Output Voltage Load Regulation, VOUT = 2.5 V
0.1 110 100 1000
OUTPUT VOLTAGE (V)
LOAD CURRENT ( mA)
VOUT = 3. 3V
3.26
3.28
3.30
3.32
3.34
3.36
3.38
3.40 VIN = 0.8V
VIN = 1.2V
VIN = 1.5V
VIN = 2.2V
VIN = 3.0V
10276-008
Figure 8. Auto Mode Output Voltage Load Regulation, VOUT = 3.3 V
Data Sheet ADP1607
Rev. C | Page 7 of 16
30
27
24
21
18
151.8 2.3 2.8 3.3
NONS WITCHING VOUT QUIE S CE NT CURRENT (µ A)
INPUT VOLTAGE (V)
TA = –40° C
TA = +25°C
TA = +45°C
TA = +85°C
10276-009
Figure 9. Nonswitching PFM Mode Quiescent Current vs. Input Voltage
5
4
3
2
1
0
0.9 1.4 1.9 2.4 2.9
SHUT DOWN CURRE NT (µ A)
INPUT VOLTAGE (V)
T
A
= –40° C
T
A
= +25°C
T
A
= +45°C
T
A
= +90°C
10276-010
Figure 10. Shutdown Current vs. Input Voltage
170
155
140
125
110
951.8 2.3 2.8 3.3
NMOS RDSON (mΩ)
OUTPUT VOLTAGE (V)
TA = –40° C
TA = +25°C
TA = +90°C
ISW = 500mA
10276-011
Figure 11. NMOS Drain-to-Source On Resistance
270
240
210
180
150
1201.8 2.3 2.8 3.3
PMOS RDSON (mΩ)
OUTPUT VOLTAGE (V)
TA = –40° C
TA = +25°C
TA = +90°C
ISW = 500mA
10276-012
Figure 12. PMOS Drain-to-Source On Resistance
1200
1100
1000
900
800
7000.8 1.3 1.8 2.3 2.8 3.3
CURRENT LIM IT ( mA)
INPUT VOLTAGE (V)
VOUT = 1. 8 V
VOUT = 2. 5V
VOUT = 3. 3V
10276-013
Figure 13. Switch Current Limit vs. Input Voltage
140
120
100
80
60
40
20
0
0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.2
LOAD CURRENT ( mA)
INPUT VOLTAGE (V)
VOUT = 2. 5V
PWM OPERATIO N
PFM OPERATION
10276-014
Figure 14. Auto Mode Transition Thresholds
ADP1607 Data Sheet
Rev. C | Page 8 of 16
88.4
88.0
87.6
87.2
86.8
86.4
1.8 2.3 2.8 3.3
MAXIMUM DUTY CYCLE (%)
OUTPUT VOLTAGE (V)
T
A
= –40°C
T
A
=+25°C
T
A
=+90°C
10276-015
Figure 15. Maximum Duty Cycle vs. Output Voltage
2.04
2.02
2.00
1.98
1.96
1.94
–40 –10 20 50 80
FREQUENCY (MHz)
TEMPERATURE (°C)
V
OUT
= 1.8V
V
OUT
= 3.3V
V
OUT
= 2.5V
10276-016
Figure 16. Frequency vs. Temperature
1000
800
600
400
200
900
700
500
300
100
0
0.8 1.3 1.8 2.3 2.8 3.3
MAXIMUM OUTPUT CURRENT (mA)
INPUT VOLTAGE (V)
V
OUT
= 1.8 V
V
OUT
= 2.5V
V
OUT
= 3.3V
10276-017
Figure 17. Maximum Output Current vs. Input Voltage
TIME (200µs/DIV)
V
IN
= 1.2V
V
OUT
= 3.3V
I
LOAD
= 1mA TO 50mA
LOAD CURRENT
(50mA/DIV)
OUTPUT VOLTAGE (100mV/DIV)
AC-COUPLED
10276-018
1
4
Figure 18. PFM Mode Load Transient Response (Auto Mode Part)
TIME (200µs/DIV)
V
IN
= 1.2V
V
OUT
= 3.3V
I
LOAD
= 50mA TO 100mA
LOAD CURRENT
(50mA/DIV)
OUTPUT VOLTAGE (100mV/DIV)
AC-COUPLED
10276-019
1
4
Figure 19. PWM Mode Load Transient Response (Fixed PWM Mode Part)
TIME (200µs/DIV)
V
IN
= 1.2V
V
OUT
= 3.3V
R
LOAD
= 3.3kΩ
EN PIN VOLTAGE
(1V/DIV)
INDUCTOR
CURRENT
(200mA/DIV)
SW PIN VOLTAGE
(2V/DIV)
OUTPUT VOLTAGE
(1V/DIV)
10276-020
1
4
3
2
Figure 20. Startup, RLOAD =3.3 kΩ
Data Sheet ADP1607
Rev. C | Page 9 of 16
TIME (200µs/DIV)
VIN = 1.2V
VOUT = 3.3V
RLOAD = 33Ω
EN PIN VOLTAGE
(1V/DIV)
INDUCTOR CURRENT
(500mA/DIV)
SW PIN VOLTAGE
(2V/DIV)
OUTPUT VOLTAGE
(1V/DIV)
10276-021
1
4
3
2
Figure 21. Startup, RLOAD = 33 Ω
TIME (10µs/DIV)
V
IN
= 1.2V
V
OUT
= 3.3V
I
LOAD
= 10mA
INDUCTOR CURRENT
(200mA/DIV)
SW PIN VOLTAGE
(2V/DIV)
OUTPUT VOLTAGE (100mV/DIV)
AC COUPLED
10276-022
1
4
2
Figure 22. Typical PFM Mode Operation, ILOAD = 10 mA
TIME (400ns/DIV)
V
IN
= 1.2V
V
OUT
= 3.3V
I
LOAD
= 100mA
INDUCTOR CURRENT
(100mA/DIV)
SW PIN VOLTAGE
(2V/DIV)
OUTPUT VOLTAGE (20mV/DIV)
AC COUPLED
10276-023
1
4
2
Figure 23. Typical PWM Mode Operation, ILOAD = 100 mA
ADP1607 Data Sheet
Rev. C | Page 10 of 16
THEORY OF OPERATION
SW
+
+
VIN
N
RESET
AGND
GND
T
SENSE
T
REF
1
V
DD
L1
A
V
OUT
C
OUT
5
24
EN
V
IN
S
R
QP
QN
RP
V
SEL
SW
P
6
V
SEL
V
IN
OFF ON
3
FB
R1
R2
V
OUT
C
IN
V
REF
PFM
COMPARATOR
PWM
COMPARATOR
CURRENT-LIMIT
COMPARATOR
TSD
COMPARATOR
PFM
CONTROL
SHUTDOWN
ZERO
CROSS
PMOS
BULK
CONTROL
P DRIVER
CURRENT
SENSING
N DRIV E R
OSCILLATOR
SOFT
START
R
COMP
C
COMP
ERROR
AMPLIFIER
V
REF
BULK
CONTROL
V
OUT
10276-033
Figure 24. Block Diagram
OVERVIEW
The ADP1607 is a high efficiency, synchronous, fixed
frequency, step-up dc-to-dc switching converter with an
adjustable output voltage between 1.8 V and 3.3 V for use
in portable applications.
The 2 MHz operating frequency enables the use of small
footprint, low profile external components. Additionally, the
synchronous rectification, internal compensation, internal fixed
current limit, and current-mode architecture allow for excellent
transient response and a minimal external part count. Other
key features include fixed PWM and light load PFM mode
options, true output isolation, thermal shutdown (TSD), and
logic controlled enable.
ENABLE/SHUTDOWN
The EN input turns the ADP1607 on or off. Connect EN to
GND or logic low to shut down the part and reduce the current
consumption to 0.06 µA (typical). Connect EN to VIN or logic
high to enable the part. Do not exceed VIN. Do not leave this pin
floating.
MODES OF OPERATION
The ADP1607 is available in a fixed PWM mode only option
for noise sensitive applications or in an auto PFM-to-PWM
transitioning mode option to optimize power at light loads.
Pulse-Width Modulation (PWM) Mode
The PWM version of the ADP1607 utilizes a current-mode
PWM control scheme to force the part to maintain a fixed
2 MHz fixed frequency while regulating the output voltage over
all load conditions. The auto mode version of the ADP1607
operates in PWM for higher load currents. In PWM, the output
voltage is monitored at the FB pin through the external resistive
voltage divider. The voltage at FB is compared to the internal
1.259 V reference by the internal error amplifier. This current-
mode PWM regulation system allows fast transient response
and tight output voltage regulation. PWM mode operation
results in lower efficiencies than PFM mode at light loads.
Auto Mode
Auto mode is a power-saving feature that forces the auto version
of the ADP1607 to switch between PFM and PWM in response
to output load changes. The auto version of the ADP1607
Data Sheet ADP1607
Rev. C | Page 11 of 16
operates in PFM mode for light load currents and switches to
PWM mode for medium and heavy load currents.
Pulse Frequency Modulation (PFM)
When the auto mode version of the ADP1607 is operating
under light load conditions, the effective switching frequency
and supply current are decreased and varied using PFM to
regulate the output voltage. This results in improved efficiencies
and lower quiescent currents. In PFM mode, the converter only
switches when necessary to keep the output voltage between the
PFM comparator high output voltage threshold and the lower
sleep mode exit voltage threshold. Switching stops when the
upper PFM limit is reached and resumes when the lower sleep
mode exit threshold is reached.
When VOUT exceeds the upper PFM threshold, switching stops
and the part enters sleep mode. In sleep mode, the ADP1607 is
mostly shut down, significantly reducing the quiescent current.
The output voltage is then discharged by the load until the
output voltage reaches the lower sleep mode exit threshold.
After crossing the lower sleep mode exit threshold, switching
resumes and the process repeats.
Mode Transition
The auto mode version of the ADP1607 switches automatically
between PFM and PWM modes to maintain optimal efficiency.
Switching to PFM allows the converter to save power by sup-
plying the lighter load current with fewer switching cycles. The
mode transition point depends on the operating conditions.
See Figure 14 for typical transition levels for VOUT = 2.5 V.
Hysteresis exists in the transition point to prevent instability
and decreased efficiencies that may result if the converter
oscillates between PFM and PWM for a fixed input voltage and
load current.
The output voltage in PWM can be above or below the PFM
voltage of that part.
INTERNAL CONTROL FEATURES
Input to Output Isolation
While in shutdown, the ADP1607 manages the voltage of the
bulk of the PMOS to force it off and internally isolate the path
from the input to output. This allows the output to drop to
ground, reducing the current consumption of the application
in shutdown.
Soft Start
The ADP1607 soft start sequence is designed for optimal
control of the part. When EN goes high, or when the part
recovers from a TSD, the start-up sequence begins. The output
voltage increases through a sequence of stages to ensure that
the internal circuitry is powered up in the correct order as the
output voltage rises to its final value.
Current Limit
The ADP1607 is designed with a fixed 1 A typical current limit
that does not vary with duty cycle.
Synchronous Rectification
In addition to the N-channel MOSFET switch, the ADP1607
has a P-channel MOSFET switch to build the synchronous
rectifier. The synchronous rectifier improves efficiency,
especially for heavy load currents, and reduces cost and board
space by eliminating the need for an external Schottky diode.
Compensation
The PWM control loop of the ADP1607 is internally compen-
sated to deliver maximum performance with no additional
external components. The ADP1607 is designed to work with
2.2 μH chip inductors and 10 μF ceramic capacitors. Other
values may reduce performance and/or stability.
Thermal Shutdown (TSD) Protection
The ADP1607 includes thermal shutdown (TSD) protection
when the part is in PWM mode only. If the die temperature
exceeds 150°C (typical), the TSD protection activates and turns
off the power devices. They remain off until the die temperature
falls below 135°C (typical), at which point the converter
restarts.
ADP1607 Data Sheet
Rev. C | Page 12 of 16
APPLICATIONS INFORMATION
SETTING THE OUTPUT VOLTAGE
The ADP1607 can be configured for output voltages between
1.8 V and 3.3 V. The output voltage is set by a resistor voltage
divider, R1, from the output voltage (VOUT) to the 1.259 V
feedback input at FB and R2 from FB to GND (see Figure 24).
Resistances between 100 kΩ and 1 MΩ are recommended.
For larger R1 and R2 values, the voltage drop due to the FB pin
current (IFB) on R1 becomes proportionally significant and
needs to be factored in.
To account for the effect of IFB for all values of R1 and R2,
use the following equation to determine R1 and R2 for the
desired VOUT:
)(1 R1IV
R2
R1
VFBFBOUT +
+=
(1)
where:
VFB = 1.259 V, typical
IFB = 0.1 µA, typical
INDUCTOR SELECTION
The ADP1607 is designed with a 2 MHz operating frequency
enabling the use of small chip inductors ideal for use in
applications with limited solution size constraints. The
ADP1607 is designed for optimal performance with 2.2 µH
inductors, which have favorable saturation currents and lower
series resistances for their given physical size.
To ensure stable and efficient performance with the ADP1607,
care should be taken to select a compatible inductor with a
sufficient current rating, saturation current, and low dc
resistance (DCR.)
The maximum rated rms current of the inductor must be
greater than the maximum input current to the regulator.
Likewise, the saturation current of the chosen inductor must be
able to support the peak inductor current (the maximum input
current plus half the inductor ripple current) of the application.
The inductor ripple current (∆IL) in steady state continuous
mode can be calculated as
SW
IN
L
fL DV
I×
×
=∆
(2)
where:
D is the duty cycle of the application.
L is the inductor value.
fSW is the switching frequency of the ADP1607.
The switch duty cycle (D) is determined by the input (VIN) and
output (VOUT) voltages with the following equation:
OUT
IN
OUT
V
VV
D−
=
(3)
Inductors with a low DCR minimize power loss and improve
efficiency. DCR values below 100 mΩ are recommended.
Table 5. Suggested Inductors
Manufacturer Part Number
Inductance
(µH)
DCR (mΩ)
Typ
Current
Rating (A)
Saturation
Current (A) Size (L × W × H) (mm) Package
TDK MLP2016S2R2M 2.2 ± 20% 110 1.20 2.00 × 1.60 × 1.00 0806
MLP2520S2R2S 2.2 ± 20% 110 1.20 1.20 2.50 × 2.00 × 1.00 1008
VLF252012MT-2R2M 2.2 ± 20% 57 1.67 1.04 2.50 × 2.00 × 1.00 1008
VLF302510MT-2R2M 2.2 ± 20% 70 1.23 1.37 3.00 × 2.50 × 1.00
VLF302515MT-2R2M
2.2 ± 20%
42
2.71
1.57
3.00 × 2.50 × 1.40
Murata LQM2HPN2R2MG0 2.2 ± 20% 80 1.30 2.50 × 2.00 × 0.90 1008
LQH32PN2R2NNC 2.2 ± 30% 64 1.85 3.20 × 2.50 × 1.55 1210
Wurth
74479787222
2.2 ± 20%
80
1.50
0.70
2.50 × 2.00 × 1.00
1008
7440430022 2.2 ± 30% 23 2.50 2.35 4.80 × 48.0 × 2.80
Taiyo Yuden BRC2012T2R2MD 2.2 ± 20% 110 1.00 1.10 2.00 × 1.25 × 1.40 0805
Toko MDT2520-CR2R2M 2.2 ± 20% 90 1.35 2.50 × 2.00 × 1.00 1008
DEM2810C (1224AS-H-2R2M) 2.2 ± 20% 85 1.10 1.40 3.20 × 3.00 × 1.00
DEM2815C (1226AS-H-2R2M) 2.2 ± 20% 43 1.40 2.20 3.20 × 3.00 × 1.50
Coilcraft XFL3012-222 2.2 ± 20% 81 1.9 1.6 3.00 × 3.00 × 1.20 1212
XFL4020-222 2.2 ± 10% 21 8.0 3.1 4.00 × 4.00 × 2.10 1515
Data Sheet ADP1607
Rev. C | Page 13 of 16
CHOOSING THE INPUT CAPACITOR
The ADP1607 requires a 10 µF or greater input bypass capacitor
(CIN) between VIN and GND to supply transient currents while
maintaining a constant input voltage. The value of the input
capacitor can be increased without any limit for smaller input
voltage ripple and better input voltage filtering. The capacitor must
have a 4 V or higher voltage rating to support the maximum
input operating voltage. It is recommended that CIN be placed as
close to the ADP1607 as possible.
Different types of capacitors can be considered, but for battery-
powered applications, the best choice is the multilayer ceramic
capacitor, due to its small size, low equivalent series resistance
(ESR), and low equivalent series inductance (ESL). X5R or X7R
dielectrics are recommended. Y5V capacitors should not be used
due to their variation in capacitance over temperature. Alterna-
tively, use a high value, medium ESR capacitor in parallel with a
0.1 µF low ESR capacitor.
CHOOSING THE OUTPUT CAPACITOR
The ADP1607 also requires a 10 µF output capacitor (COUT) to
maintain the output voltage and supply current to the load. The
output capacitor supplies the current to the load when the N-
channel switch is turned on. Similar to CIN, a 4 V or greater, low
ESR, X5R or X7R ceramic capacitor is recommended for COUT.
When choosing the output capacitor, it is also important to account
for the loss of capacitance due to output voltage dc bias. This
may result in using a capacitor with a higher rated voltage to
achieve the desired capacitance value. See Figure 25 for an
example of how the capacitance of a 10 µF ceramic capacitor
changes with the dc bias voltage.
0
2
4
6
8
10
12
0123456
10276-034
DC BIAS V OLTAGE ( V )
CAPACI TANCE (µ F)
Figure 25. Typical Ceramic Capacitor Performance
The value and characteristics of the output capacitor greatly
affect the output voltage ripple, transient performance, and
stability of the regulator. The output voltage ripple (∆VOUT) in
continuous operation is calculated as follows:
OUT
ON
OUT
OUT
C
OUT
C
t
I
C
Q
V×
==
∆
(4)
where:
QC is the charge removed from the capacitor.
tON is the on time of the N-channel switch.
COUT is the effective output capacitance.
IOUT is the output load current.
SW
ON
f
D
t=
(5)
and,
OUT
IN
OUT
V
VV
D−
=
(6)
As shown in the duty cycle and output ripple voltage equations,
the output voltage ripple increases with the load current.
ADP1607 Data Sheet
Rev. C | Page 14 of 16
LAYOUT GUIDELINES
10276-035
1
2
34
5
6
EN
GND
SW
VOUT
FB
VIN
R1
0402 R2
0402
C
OUT
0402
C
IN
0402
3.0mm
6.5mm
ADP1607
TOP VI EW
7
EPAD
L
2.2µH
0805
Figure 26. ADP1607 Recommended Layout Showing the Smallest Footprint
For high efficiency, good regulation, and stability, a well-
designed printed circuit board layout is required.
Use the following guidelines when designing printed circuit
boards (also see Figure 24 for a block diagram and Figure 2 for
a pin configuration).
• Keep the low ESR input capacitor, CIN, close to VIN and
GND. This minimizes noise injected into the part from
board parasitic inductance.
• Keep the high current path from CIN through the L1
inductor to SW as short as possible.
• Place the feedback resistors, R1 and R2, as close to FB as
possible to prevent noise pickup. Connect the ground of
the feedback network directly to an AGND plane that
makes a Kelvin connection to the GND pin.
• Avoid routing high impedance traces from feedback
resistors near any node connected to SW or near the
inductor to prevent radiated noise injection.
• Keep the low ESR output capacitor, COUT, close to VOUT
and GND. This minimizes noise injected into the part from
board parasitic inductance.
• Connect Pin 7 (EPAD) and GND to a large copper plane
for proper heat dissipation.
Data Sheet ADP1607
Rev. C | Page 15 of 16
OUTLINE DIMENSIONS
1.70
1.60
1.50
0.425
0.350
0.275
TOP VIEW
6
1
4
3
0.35
0.30
0.25
BOTTOM VIEW
PIN 1 INDEX
AREA
SEATING
PLANE
0.60
0.55
0.50
1.10
1.00
0.90
0.20 RE F
0.05 MAX
0.02 NOM
0.65 BSC
EXPOSED
PAD
PIN 1
INDICATOR
(R 0.15)
FOR PROPER CONNECTION O F
THE EXPOSED PAD, REFER TO
THE P IN CO NFI GURAT IO N AND
FUNCTION DESCRIP TIONS
SECTION OF THIS DATA SHEET.
02-06-2013-D
0.15 RE F
2.10
2.00 SQ
1.90
0.20 MIN
Figure 27. 6-Lead Lead Frame Chip Scale Package [LFCSP_UD]
2.00 mm × 2.00 mm Body, Ultra Thin, Dual Lead
(CP-6-3)
Dimensions shown in millimeters
ORDERING GUIDE
Model1
Output
Voltage
Operating
Modes
Temperature
Range Package Description
Package
Option Branding
ADP1607ACPZN-R7 Adjustable Auto –40°C to +85°C 6-Lead LFCSP_UD CP-6-3 LJ5
ADP1607ACPZN001-R7 Adjustable PWM –40°C to +85°C 6-Lead LFCSP_UD CP-6-3 LJ1
ADP1607-EVALZ Auto Evaluation Board, Automatic PFM/PWM
Switching Modes
ADP1607-001-EVALZ PWM Evaluation Board, PWM Mode Only
1 Z = RoHS Compliant Part.
ADP1607 Data Sheet
Rev. C | Page 16 of 16
NOTES
©2012–2013 Analog Devices, Inc. All rights reserved. Trademarks and
registered trademarks are the property of their respective owners.
D10276-0-12/13(C)
