AD ADP1607-EVALZ 2 mhz, synchronous boost dc-to-dc converter Datasheet

2 MHz, Synchronous Boost
DC-to-DC Converter
ADP1607
Data Sheet
FEATURES
GENERAL DESCRIPTION
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
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.
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
TYPICAL APPLICATION CIRCUIT
L
2.2µH
INPUT VOLTAGE
0.8V TO VOUT
ADP1607
1
ADJUSTABLE
OUTPUT VOLTAGE
1.8V TO 3.3V
SW 5
VIN
CIN
10µF
VOUT 6
R1
2
EN
GND
4
FB 3
R2
COUT
10µF
10276-001
ON
OFF
Figure 1.
Rev. C
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ADP1607
Data Sheet
TABLE OF CONTENTS
Features .............................................................................................. 1
Overview ..................................................................................... 10
Applications ....................................................................................... 1
Enable/Shutdown ....................................................................... 10
General Description ......................................................................... 1
Modes of Operation ................................................................... 10
Typical Application Circuit ............................................................. 1
Internal Control Features .......................................................... 11
Revision History ............................................................................... 2
Applications Information .............................................................. 12
Specifications..................................................................................... 3
Setting the Output Voltage ........................................................ 12
Absolute Maximum Ratings ............................................................ 4
Inductor Selection ...................................................................... 12
Thermal Operating Ranges ......................................................... 4
Choosing the Input Capacitor .................................................. 13
Thermal Resistance ...................................................................... 4
Choosing the Output Capacitor ............................................... 13
ESD Caution .................................................................................. 4
Layout Guidelines ........................................................................... 14
Pin Configuration and Function Descriptions ............................. 5
Outline Dimensions ....................................................................... 15
Typical Performance Characteristics ............................................. 6
Ordering Guide .......................................................................... 15
Theory of Operation ...................................................................... 10
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
Rev. C | Page 2 of 16
Data Sheet
ADP1607
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
SUPPLY
Minimum Start-Up Voltage 2
Operating Input Voltage Range 3
Shutdown Current
Quiescent Current
Soft Start Time
SWITCH
Current Limit
NMOS On Resistance
PMOS On Resistance
SW Leakage Current
OSCILLATOR
Switching Frequency
Maximum Duty Cycle
OUTPUT
VOUT Range
FB Pin Voltage
FB Pin Current
EN/MODE LOGIC
Input Voltage Threshold Low
Input Voltage Threshold High
EN/MODE Leakage Current
THERMAL SHUTDOWN 5
Thermal Shutdown Threshold
Thermal Shutdown Hysteresis
Symbol
VIN
IQSD
ICL
RDSON_N
RDSON_P
Test Conditions/Comments
Min
RMIN = 22 Ω
0.9
0.8
Max
Unit
0.06
VOUT
0.67
V
V
µA
23
23
29
40
µA
µA
6
6
1.3
11
14.6
µA
µA
ms
0.8
1
116
155
0.18
1.3
165
225
2
A
mΩ
mΩ
µA
1.8
85
2
90
2.2
MHz
%
3.3
1.2842
0.25
V
V
µA
0.25
V
V
µA
VEN = GND, VOUT = GND, TA = −40°C to +45°C 4
Nonswitching, measured on VOUT, auto
operating mode part only
TA = −40°C to +45°C
TA = −40°C to +85°C
Measured on VIN
TA = −40°C to +45°C
TA = −40°C to +85°C
ISW = 500 mA
ISW = 500 mA
VSW = 1.2 V, VOUT = 0 V, TA = −40°C to +45°C4
fSW
DMAX
VOUT
VFB
IFB
Typ
PWM mode
VFB = 1.26 V
VIL
VIH
1.8
1.2338
1.259
0.1
0.8
VEN = GND or VIN, VOUT = 0 V
0.001
150
15
0.25
°C
°C
All limits at temperature extremes are guaranteed via correlation using standard statistical quality control (SQC). Specifications are subject to change without notice.
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.
1
2
Rev. C | Page 3 of 16
ADP1607
Data Sheet
ABSOLUTE MAXIMUM RATINGS
Table 2.
Parameter
VIN, VOUT to GND
FB to GND
EN, SW to GND (when VIN ≥ VOUT)
EN, SW to GND (when VIN < VOUT)
EPAD to GND
Operating Ambient Temperature Range
Operating Junction Temperature Range
Storage Temperature Range
Soldering Conditions
Rating
−0.3 V to +3.6 V
−0.3 V to +1.4 V
−0.3 V to VIN + 0.3 V
−0.3 V to VOUT + 0.3 V
−0.3 V to + 0.3 V
−40°C to +85°C
−40°C to +90°C
−65°C to +150°C
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.
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.
THERMAL OPERATING RANGES
The ADP1607 can be damaged when the junction temperature 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.
Package Type
6-Lead LFCSP
ESD CAUTION
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.
Rev. C | Page 4 of 16
θJA
66.06
θJC
4.3
Unit
°C/W
Data Sheet
ADP1607
PIN CONFIGURATION AND FUNCTION DESCRIPTIONS
VIN 1
6 VOUT
ADP1607
FB 3
TOP VIEW
(Not to Scale)
7
EPAD
5 SW
4 GND
NOTES
1. CONNECT THE EXPOSED PAD TO GND.
10276-002
EN 2
Figure 2. Pin Configuration
Table 4. Pin Function Descriptions
Pin No.
1
2
3
4
5
6
7
Mnemonic
VIN
EN
FB
GND
SW
VOUT
EPAD
Description
Analog and Power Supply Pin.
Shutdown Control Pin. Drive EN high to turn on the synchronous boost, drive EN low to turn it off.
Output Voltage Feedback Pin.
Analog and Power Ground Pin.
Drain Connection for NMOS and PMOS Power Switches.
Output Voltage and Source Connection of PMOS Power Switch.
Exposed Pad. Connect to GND.
Rev. C | Page 5 of 16
ADP1607
Data Sheet
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.
1.84
VOUT = 1.8V
VIN = 0.8V
VIN = 1.2V
VIN = 1.5V
VOUT = 1.8V
90
1.83
OUTPUT VOLTAGE (V)
80
60
50
40
30
20
10
100
1000
LOAD CURRENT (mA)
1.78
0.1
2.56
VOUT = 2.5V
100
OUTPUT VOLTAGE (V)
2.54
70
60
50
40
30
0
0.1
1
10
100
1000
LOAD CURRENT (mA)
2.52
2.51
2.50
2.48
2.47
0.1
10276-004
10
2.53
2.49
VIN = 0.8V
VIN = 1.2V
VIN = 1.5V
VIN = 2.2V
20
1
10
100
Figure 7. Auto Mode Output Voltage Load Regulation, VOUT = 2.5 V
3.40
VOUT = 3.3V
VOUT = 3.3V
VIN = 0.8V
VIN = 1.2V
VIN = 1.5V
VIN = 2.2V
VIN = 3.0V
90
3.38
OUTPUT VOLTAGE (V)
80
60
50
40
30
VIN = 0.8V
VIN = 1.2V
VIN = 1.5V
VIN = 2.2V
VIN = 3.0V
0
0.1
1
10
100
1000
LOAD CURRENT (mA)
3.36
3.34
3.32
3.30
3.28
10276-005
EFFICIENCY (%)
70
10
1000
LOAD CURRENT (mA)
Figure 4. Auto Mode Efficiency vs. Load Current, VOUT = 2.5 V
20
1000
VIN = 0.8V
VIN = 1.2V
VIN = 1.5V
VIN = 2.2V
VOUT = 2.5V
2.55
80
EFFICIENCY (%)
10
Figure 6. Auto Mode Output Voltage Load Regulation, VOUT = 1.8 V
90
100
1
LOAD CURRENT (mA)
Figure 3. Auto Mode Efficiency vs. Load Current, VOUT = 1.8 V
100
1.80
10276-006
1
10276-003
0
0.1
1.81
1.79
VIN = 0.8V
VIN = 1.2V
VIN = 1.5V
10
1.82
10276-007
EFFICIENCY (%)
70
Figure 5. Auto Mode Efficiency vs. Load Current, VOUT = 3.3 V
3.26
0.1
1
10
100
1000
LOAD CURRENT (mA)
Figure 8. Auto Mode Output Voltage Load Regulation, VOUT = 3.3 V
Rev. C | Page 6 of 16
10276-008
100
ADP1607
270
30
ISW = 500mA
240
PMOS RDSON (mΩ)
27
24
21
TA = –40°C
TA = +25°C
TA = +45°C
TA = +85°C
15
1.8
3.3
2.8
2.3
INPUT VOLTAGE (V)
210
TA = +90°C
180
TA = +25°C
150
TA = –40°C
120
1.8
3.3
2.8
OUTPUT VOLTAGE (V)
Figure 12. PMOS Drain-to-Source On Resistance
Figure 9. Nonswitching PFM Mode Quiescent Current vs. Input Voltage
1200
5
TA = –40°C
TA = +25°C
TA = +45°C
TA = +90°C
VOUT = 3.3V
VOUT = 2.5V
1100
VOUT = 1.8 V
CURRENT LIMIT (mA)
4
3
2
1000
900
800
1
1.4
1.9
2.4
700
0.8
10276-010
0
0.9
2.9
INPUT VOLTAGE (V)
1.8
1.3
2.3
3.3
2.8
INPUT VOLTAGE (V)
10276-013
SHUTDOWN CURRENT (µA)
2.3
10276-012
18
10276-009
NONSWITCHING VOUT QUIESCENT CURRENT (µA)
Data Sheet
Figure 13. Switch Current Limit vs. Input Voltage
Figure 10. Shutdown Current vs. Input Voltage
140
170
ISW = 500mA
120
LOAD CURRENT (mA)
TA = +90°C
140
125
TA = +25°C
100
PWM OPERATION
80
60
40
110
20
PFM OPERATION
95
1.8
2.3
2.8
OUTPUT VOLTAGE (V)
3.3
0
0.8
1.0
1.2
1.4
1.6
VOUT = 2.5V
1.8
2.0
INPUT VOLTAGE (V)
Figure 14. Auto Mode Transition Thresholds
Figure 11. NMOS Drain-to-Source On Resistance
Rev. C | Page 7 of 16
2.2
10276-014
TA = –40°C
10276-011
NMOS RDSON (mΩ)
155
ADP1607
Data Sheet
88.4
VIN = 1.2V
VOUT = 3.3V
ILOAD = 1mA TO 50mA
MAXIMUM DUTY CYCLE (%)
88.0
1
TA = +90°C
TA = –40°C
87.6
OUTPUT VOLTAGE (100mV/DIV)
AC-COUPLED
87.2
TA = +25°C
LOAD CURRENT
(50mA/DIV)
86.8
2.3
2.8
3.3
OUTPUT VOLTAGE (V)
TIME (200µs/DIV)
10276-015
86.4
1.8
Figure 15. Maximum Duty Cycle vs. Output Voltage
10276-018
4
Figure 18. PFM Mode Load Transient Response (Auto Mode Part)
2.04
VIN = 1.2V
VOUT = 3.3V
ILOAD = 50mA TO 100mA
FREQUENCY (MHz)
2.02
1
VOUT = 3.3V
OUTPUT VOLTAGE (100mV/DIV)
AC-COUPLED
2.00
VOUT = 2.5V
1.98
VOUT = 1.8V
1.96
–10
20
50
TIME (200µs/DIV)
10276-016
1.94
–40
80
TEMPERATURE (°C)
Figure 19. PWM Mode Load Transient Response (Fixed PWM Mode Part)
Figure 16. Frequency vs. Temperature
1000
VIN = 1.2V
VOUT = 3.3V
RLOAD = 3.3kΩ
VOUT = 2.5V
VOUT = 3.3V
VOUT = 1.8 V
700
OUTPUT VOLTAGE
(1V/DIV)
SW PIN VOLTAGE
(2V/DIV)
1
600
500
2
INDUCTOR
CURRENT
(200mA/DIV)
400
300
EN PIN VOLTAGE
(1V/DIV)
100
0
0.8
3
1.3
1.8
2.3
2.8
INPUT VOLTAGE (V)
3.3
TIME (200µs/DIV)
Figure 20. Startup, RLOAD =3.3 kΩ
Figure 17. Maximum Output Current vs. Input Voltage
Rev. C | Page 8 of 16
10276-020
4
200
10276-017
MAXIMUM OUTPUT CURRENT (mA)
900
800
10276-019
LOAD CURRENT
(50mA/DIV)
4
Data Sheet
ADP1607
VIN = 1.2V
VOUT = 3.3V
RLOAD = 33Ω
OUTPUT VOLTAGE (20mV/DIV)
AC COUPLED
OUTPUT VOLTAGE
(1V/DIV)
1
SW PIN VOLTAGE
(2V/DIV)
SW PIN VOLTAGE
(2V/DIV)
1
2
2
INDUCTOR CURRENT
(500mA/DIV)
10276-021
EN PIN VOLTAGE
(1V/DIV)
VIN = 1.2V
VOUT = 3.3V
ILOAD = 100mA
3
TIME (200µs/DIV)
4
TIME (400ns/DIV)
Figure 21. Startup, RLOAD = 33 Ω
Figure 23. Typical PWM Mode Operation, ILOAD = 100 mA
OUTPUT VOLTAGE (100mV/DIV)
AC COUPLED
1
SW PIN VOLTAGE
(2V/DIV)
2
INDUCTOR CURRENT
(200mA/DIV)
VIN = 1.2V
VOUT = 3.3V
ILOAD = 10mA
10276-022
4
TIME (10µs/DIV)
INDUCTOR CURRENT
(100mA/DIV)
Figure 22. Typical PFM Mode Operation, ILOAD = 10 mA
Rev. C | Page 9 of 16
10276-023
4
ADP1607
Data Sheet
THEORY OF OPERATION
L1
VIN
SW
5
VIN
1
CIN
BULK
CONTROL
VOUT
VDD
VIN
VSEL
VSEL
+
VOUT
R1
ERROR
AMPLIFIER
VOUT
6
CURRENT
SENSING
COUT
P
FB
OSCILLATOR
3
R2
A
+
PWM
COMPARATOR
PMOS
BULK
CONTROL
P DRIVER
VREF
RCOMP
CCOMP
QP
S
CURRENT-LIMIT
COMPARATOR
N DRIVER
SW
N
QN
R
SOFT
START
RP
RESET
ZERO
CROSS
TSD
COMPARATOR
TSENSE
TREF
SHUTDOWN
PFM
COMPARATOR
VREF
2
4
GND
10276-033
EN
AGND
PFM
CONTROL
ON
OFF
Figure 24. Block Diagram
OVERVIEW
MODES OF OPERATION
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 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.
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.
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 currentmode 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
Rev. C | Page 10 of 16
Data Sheet
ADP1607
operates in PFM mode for light load currents and switches to
PWM mode for medium and heavy load currents.
INTERNAL CONTROL FEATURES
Pulse Frequency Modulation (PFM)
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.
Input to Output Isolation
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 supplying 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.
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 compensated 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.
Rev. C | Page 11 of 16
ADP1607
Data Sheet
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:
VOUT
R1 

= 1 +
VFB + I FB ( R1)
R2 

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
∆I L =
(1)
where:
VFB = 1.259 V, typical
VIN × D
L × f SW
(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:
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.
D=
VOUT − VIN
(3)
VOUT
Inductors with a low DCR minimize power loss and improve
efficiency. DCR values below 100 mΩ are recommended.
Table 5. Suggested Inductors
Manufacturer
TDK
Murata
Wurth
Taiyo Yuden
Toko
Coilcraft
Part Number
MLP2016S2R2M
MLP2520S2R2S
VLF252012MT-2R2M
VLF302510MT-2R2M
VLF302515MT-2R2M
LQM2HPN2R2MG0
LQH32PN2R2NNC
74479787222
7440430022
BRC2012T2R2MD
MDT2520-CR2R2M
DEM2810C (1224AS-H-2R2M)
DEM2815C (1226AS-H-2R2M)
XFL3012-222
XFL4020-222
Inductance
(µH)
2.2 ± 20%
2.2 ± 20%
2.2 ± 20%
2.2 ± 20%
2.2 ± 20%
2.2 ± 20%
2.2 ± 30%
2.2 ± 20%
2.2 ± 30%
2.2 ± 20%
2.2 ± 20%
2.2 ± 20%
2.2 ± 20%
2.2 ± 20%
2.2 ± 10%
DCR (mΩ)
Typ
110
110
57
70
42
80
64
80
23
110
90
85
43
81
21
Current
Rating (A)
1.20
1.20
1.67
1.23
2.71
1.30
1.85
1.50
2.50
1.00
1.35
1.10
1.40
1.9
8.0
Rev. C | Page 12 of 16
Saturation
Current (A)
1.20
1.04
1.37
1.57
0.70
2.35
1.10
1.40
2.20
1.6
3.1
Size (L × W × H) (mm)
2.00 × 1.60 × 1.00
2.50 × 2.00 × 1.00
2.50 × 2.00 × 1.00
3.00 × 2.50 × 1.00
3.00 × 2.50 × 1.40
2.50 × 2.00 × 0.90
3.20 × 2.50 × 1.55
2.50 × 2.00 × 1.00
4.80 × 48.0 × 2.80
2.00 × 1.25 × 1.40
2.50 × 2.00 × 1.00
3.20 × 3.00 × 1.00
3.20 × 3.00 × 1.50
3.00 × 3.00 × 1.20
4.00 × 4.00 × 2.10
Package
0806
1008
1008
1008
1210
1008
0805
1008
1212
1515
Data Sheet
ADP1607
CHOOSING THE INPUT 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 Nchannel 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.
10
8
6
4
2
0
0
1
2
3
4
5
DC BIAS VOLTAGE (V)
6
10276-034
Different types of capacitors can be considered, but for batterypowered 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. Alternatively, use a high value, medium ESR capacitor in parallel with a
0.1 µF low ESR capacitor.
12
CAPACITANCE (µF)
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.
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:
∆VOUT =
I
×t
QC
= OUT ON
COUT
COUT
(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.
t ON =
D
f SW
(5)
and,
D=
VOUT − VIN
VOUT
(6)
As shown in the duty cycle and output ripple voltage equations,
the output voltage ripple increases with the load current.
Rev. C | Page 13 of 16
ADP1607
Data Sheet
LAYOUT GUIDELINES
CIN
0402
For high efficiency, good regulation, and stability, a welldesigned printed circuit board layout is required.
COUT
0402
Use the following guidelines when designing printed circuit
boards (also see Figure 24 for a block diagram and Figure 2 for
a pin configuration).
VOUT
6
VIN 1
ADP1607
EN 2
TOP VIEW
•
5 SW
4 GND
FB 3
R1
0402
6.5mm
7
EPAD
•
R2
0402
•
L
2.2µH
0805
10276-035
3.0mm
•
Figure 26. ADP1607 Recommended Layout Showing the Smallest Footprint
•
•
Rev. C | Page 14 of 16
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
OUTLINE DIMENSIONS
1.70
1.60
1.50
2.10
2.00 SQ
1.90
0.65 BSC
6
PIN 1 INDEX
AREA
0.15 REF
1.10
1.00
0.90
EXPOSED
PAD
0.425
0.350
0.275
3
TOP VIEW
0.60
0.55
0.50
SEATING
PLANE
0.05 MAX
0.02 NOM
0.35
0.30
0.25
0.20 MIN
1
BOTTOM VIEW
PIN 1
INDICATOR
(R 0.15)
FOR PROPER CONNECTION OF
THE EXPOSED PAD, REFER TO
THE PIN CONFIGURATION AND
FUNCTION DESCRIPTIONS
SECTION OF THIS DATA SHEET.
0.20 REF
02-06-2013-D
4
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
ADP1607ACPZN-R7
ADP1607ACPZN001-R7
ADP1607-EVALZ
ADP1607-001-EVALZ
1
Output
Voltage
Adjustable
Adjustable
Operating
Modes
Auto
PWM
Auto
PWM
Temperature
Range
–40°C to +85°C
–40°C to +85°C
Package Description
6-Lead LFCSP_UD
6-Lead LFCSP_UD
Evaluation Board, Automatic PFM/PWM
Switching Modes
Evaluation Board, PWM Mode Only
Z = RoHS Compliant Part.
Rev. C | Page 15 of 16
Package
Option
CP-6-3
CP-6-3
Branding
LJ5
LJ1
ADP1607
Data Sheet
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)
Rev. C | Page 16 of 16