ADP1864 & ADP1611 Reference Design

Preliminary Technical Data
ADP1864 and ADP1611
Reference Power Design
FCDC 00047
FEATURES
Input Voltage 5V +/- 5%
Generates two voltages: An adjustable negative voltage that tracks an adjustable positive voltage
Output Voltage: -7V to -12V and +7 to +12V
Single resistor value change for each supply will adjust the output voltages
Both Voltages capable of providing 150mA of output current
ADP1864 AND ADP1611 REFERENCE POWER DESIGN DESCRIPTION
The ADP1611 and ADP1864 switching power controllers generate positive and negative voltage rails respectively, which is
ideal for powering multiple ADC and OpAmps. With the feedback configuration the negative rail will track the positive
rail, so as the positive rail becomes more positive, the negative rail will become more negative at the same rate. The
tracking is also active during startup.
This ADP1864 a current mode controller used in the inverting boost topology. The ADP1864 switches at 580kHz with a
duty cycle of 58% and 70% when generating -7V, and -12V respectively. A single small IC integrates the PFET and power
diode offering a compact solution. Only a single small MLCC output capacitor is necessary to provide adequate
capacitance and ripple current handling. The output voltage of this circuit is adjustable from -7V to -12V via a single
resistor value change.
The ADP1611 is used in the boost topology and switches at 1.2MHz nominally. The circuit operates at 58% and 29% when
generating +12 and +7 respectively. The ADP1611 is a current mode controller with integrated power switch to provide a
compact solution. This output voltage of this circuit is adjustable from +7V to +12V via a single resistor value change.
Only a single small 4.7uF MLCC output capacitor is necessary to provide adequate capacitance and ripple current handling.
Rev. 0
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©2007 Analog Devices, Inc. All rights reserved
Preliminary Technical Data
FCDC 00047
TABLE OF CONTENTS
Features....................................................................................................................................................................................................... 1
ADP1864 and ADP1611 Reference Power Design Description........................................................................................................ 1
Revision History........................................................................................................................................................................................ 2
General Description ................................................................................................................................................................................. 3
ADP1611................................................................................................................................................................................................ 3
ADP1864................................................................................................................................................................................................ 3
Schematic ................................................................................................................................................................................................... 4
Bill of Materials ......................................................................................................................................................................................... 5
REVISION HISTORY
07/11/2007—Revision 0: Initial Version
Rev. A | Page 2 of 6
Preliminary Technical Data
FCDC 00047
GENERAL DESCRIPTION
ADP1611
The ADP1611 is a step-up dc-to-dc switching converter with an integrated 1.2 A, 0.23 Ω power switch capable of providing
an output voltage as high as 20 V. With a package height of less than 1.1 mm, the ADP1611 is optimal for space-constrained
applications such as portable devices or thin film transistor (TFT) liquid crystal displays (LCDs).
The ADP1611 operates in pulse-width modulation (PWM) current mode with up to 90% efficiency. Adjustable soft start
prevents inrush currents at startup. The pin-selectable switching frequency and PWM current-mode architecture allow
excellent transient response, easy noise filtering, and the use of small, cost-saving external inductors and capacitors.
The ADP1611 is offered in the Pb-free 8-lead MSOP and operates over the temperature range of −40°C to +85°C.
ADP1864
The ADP1864 is a compact, inexpensive, constant-frequency current-mode DC-to-DC controller. The ADP1864 drives a
P-channel MOSFET that regulates an output voltage as low as 0.8 V with ±2% accuracy, for up to 10 A load currents, from
input voltages as high as 14 V.
The ADP1864 provides system flexibility by allowing accurate setting of the current limit with an external resistor, while
the output voltage is easily adjustable using two external resistors. The ADP1864 includes an internal soft start to allow
quick power-up while preventing input inrush current. Additional safety features include short-circuit protection, output
over-voltage protection, and input under voltage protection. Current-mode control provides fast and stable load transient
performance, while the 580 kHz operating frequency allows a small inductor to be used in the system. To further the life of
a battery source, the controller turns on the external P-channel MOSFET 100% of the duty cycle in dropout.
The ADP1864 operates over the −40°C to +85°C temperature range and is available in a small, low profile, 6-lead TSOT
package.
Rev. A | Page 3 of 6
Preliminary Technical Data
FCDC 00047
SCHEMATIC
Figure 1.
Generating Negative and Positive Rails with Tracking using ADP1611 and ADP1864
Rev. A | Page 4 of 6
Preliminary Technical Data
FCDC 00047
BILL OF MATERIALS
Designator
Part Number
Manufacturer
U1
ADP1864
Analog Devices
U2
sia811dj
Vishay
R1
RL0510S-R050-F
Susumu
.05ohms
402
1% Current Sense Resistor
R2
Generic 1%
Vishay
20k
402
Feedback Resistor
R3
Generic 1%
Vishay
20k
402
Feedback Resistor
R13
Generic 1%
Vishay
12k
R12
Generic 1%
Vishay
287ohms
402
Feedback Resistor
R11a
Generic 1%
Vishay
4.6k
402
Feedback Resistor for -12V
R11b
Generic 1%
Vishay
2.6k
402
Feedback Resistor for -7V
R6
Generic 10%
Vishay
225k
402
Compensation Resistor
R7
Generic 10%
Vishay
510k
402
Compensation Resistor
R10
Value
Package
Comment
TSOT-6
PowerPAK
SC-70-6 Dual
Current Mode Controller
Feedback Resistor
TBD
Snubber - May be unnecessary
C1
grm21br61c475k
Murata
4.7uF
805
C2
grm32er61c476k
Murata
47uF
1210
C3
Generic 10%
Vishay
33pF
402
C9
P-Channel and Schotkey Diode
TBD
Input Capacitor / X5R / 16V
Output Capacitor / X5R / 16V
X7R or COG / 50V
Compensation Capacitor
4.7uH
5mm x 5mm x
1.5mm
4.7uH
MSOP-8
5mm x 5mm x
1.5mm
L1
LPS5015-472ML
Coilcraft
U3
ADP1611
Analog Devices
L2
LPS5015-472ML
Coilcraft
D1
PD3S130L
Diodes Inc.
C4
grm21br61c475k
Murata
4.7uF
805
Input Capacitor / X5R / 16V
C5
grm21br61c475k
Murata
4.7uF
805
C6
Generic 10%
Vishay
22nF
402
Output Capacitor / X5R / 16V
Soft Start Capacitor / X7R or COG /
50V
C7
Generic 10%
Vishay
8.2nF
402
Compensation Capacitor
C8
TBD
402
Snubber - May be unncessary
R9
TBD
402
Snubber - May be unncessary
PowerDI™323
Snubber - May be unnecessary
Current Mode Controller + Power
Switch
Power Inductor
Power Diode
R4a
Generic 1%
Vishay
87.6k
402
Feedback Resistor for +12V
R4b
Generic 1%
Vishay
46.9k
402
Feedback Resistor for +7V
R5
Generic 10%
Vishay
10k
402
Feedback Resistor
R8
Generic 10%
Vishay
7.5k
402
Compensation Resistor
Q1, Q2
2n2222
Any
NPN small signal transistor
Q3
2n2904
Any
PNP small signal transistor
Rev. A | Page 5 of 6
Preliminary Technical Data
FCDC 00047
NOTES
©2007 Analog Devices, Inc. All rights reserved.
Trademarks and registered trademarks are the
property of their respective owners.
EB
Rev. A | Page 6 of 6
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