Synchronous Buck PWM,
Step-Down, DC-to-DC Controller
ADP1828
to regulate an output voltage as low as 0.6 V to 85% of the input
voltage and is sized to handle large MOSFETs for point-of-load
regulators. The ADP1828 is ideal for a wide range of high power
applications, such as DSP and processor core I/O power, and
general-purpose power in telecommunications, medical imaging,
PC, gaming, and industrial applications. It operates from input
bias voltages of 3 V to 18 V with an internal LDO that generates
a 5 V output for input bias voltages greater than 5.5 V.
FEATURES
Wide bias voltage range 3.0 V to 18 V
Wide power stage input range 1 V to 24 V
Wide output voltage range: 0.6 V to 85% of input voltage
0.85% accuracy at 0oC to 70oC
All N-channel MOSFET design for low cost
Fixed-frequency operation at 300 kHz, 600 kHz, or resistor
adjustable 300 kHz to 600 kHz
Clock output for synchronizing other controllers
No current sense resistor required
Internal linear regulator
The ADP1828 operates at a pin-selectable, fixed switching
frequency of either 300 kHz or 600 kHz, or at any frequency
between 300 kHz and 600 kHz with a resistor. The switching
frequency can also be synchronized to an external clock up to
2× the part’s nominal oscillator frequency. The clock output
can be used for synchronizing additional ADP1828s (or the
ADP1829 controllers), thus eliminating the need for an external
clock source. The ADP1828 includes soft start protection to
limit any inrush current from the input supply during startup,
reverse current protection during soft start for a precharged
output, as well as a unique adjustable lossless current-limit
scheme utilizing external MOSFET RDSON sensing.
Voltage tracking for sequencing
Soft start and thermal overload protection
Overvoltage and undervoltage power-good indicator
15 μA shutdown supply current
Available in a 20-lead QSOP
APPLICATIONS
Telecom and networking systems
Base station power
Set-top boxes, game consoles
Printers and copiers
Medical imaging systems
DSP and microprocessor core power supplies
DDR termination
For applications requiring power-supply sequencing, the
ADP1828 provides a tracking input that allows the output
voltage to track during startup, shutdown, and faults. The
additional supervisory and control features include thermal
overload, undervoltage lockout, and power good.
GENERAL DESCRIPTION
The ADP1828 operates over the −40°C to +125°C junction
temperature range and is available in a 20-lead QSOP.
The ADP1828 is a versatile and synchronous PWM voltage
mode buck controller. It drives an all N-channel power stage
V
= 10V TO 18V
IN
C
IN
180µF
C7
1µF
×2
C5
20V
1µF
D1
BST
TRK
VREG PV
IN
C4
0.47µF
M1
DH
SW
CSL
DL
ADP1828
OUTPUT
1.8V, 20A
L1 = 0.82µH
C6
1µF
EN
R
CL
R6
100kΩ
C
OUT1
C
OUT2
R3
FREQ
SYNC
PGOOD
COMP
SS
1.8kΩ
47µF
1000µF
×2
M2
×2
7.5kΩ
X5R
6.3V
C1
680pF
PGND
R1
20kΩ
FB
CLKOUT
CLKSET
R2
10kΩ
R8
20kΩ
AGND PGND
C2
33pF
C
SS
200nF
GND
AGND
C3
5.6nF
fSW = 300kHz
D1: BAT54
C
: SANYO, OSCON 20SP180M
M1: INFINEON, BSC080N03LS
IN
C
: SANYO, POSCAP 2R5TPD1000M5
M2: INFINEON, 2 × BSC030N03LS
OUT2
L1: WURTH ELEKTRONIC, 0.82µH, 744355182
Figure 1. Typical Application Circuit with 20 A Output
Rev. 0
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