Datasheet

Synchronous Current-Mode with
Constant On-Time, PWM Buck Controller
ADP1882/ADP1883
Rev. 0
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FEATURES
Power input voltage as low as 2.75 V to 20 V
Bias supply voltage range: 2.75 V to 5.5 V
Minimum output voltage: 0.8 V
0.8 V reference voltage with ±1.0% accuracy
Supports all N-channel MOSFET power stages
Available in 300 kHz, 600 kHz, and 1.0 MHz options
No current-sense resistor required
Power saving mode (PSM) for light loads (ADP1883 only)
Resistor-programmable current-sense gain
Thermal overload protection
Short-circuit protection
Precision enable input
Integrated bootstrap diode for high-side drive
140 μA shutdown supply current
Starts into a precharged load
Small, 10-lead MSOP package
APPLICATIONS
Telecom and networking systems
Mid to high end servers
Set-top boxes
DSP core power supplies
TYPICAL APPLICATIONS CIRCUIT
COMP/EN BST
FB DRVH
GND SW
VDD DRVL
PGND
VIN
C
C
C
VDD
V
DD
= 2.75V TO 5.5V
C
VDD2
C
C2
R
C
R
BOT
R
TOP
V
OUT
V
IN
= 2.75V TO 20
V
Q1
Q2
R
RES
L
C
OUT
V
OUT
C
BST
LOAD
C
IN
ADP1882/
ADP1883
08901-001
Figure 1.
100
95
90
85
80
75
70
65
60
55
50
45
25
30
35
40
100 1k 10k 100k
EFFICIENCY (%)
LOAD CURRENT (mA)
V
DD
= 5.5V, V
IN
= 13.0V
V
DD
= 5.5V, V
IN
= 16.5V
V
DD
= 5.5V, V
IN
= 5.5V (PSM)
V
DD
= 5.5V, V
IN
= 5.5V
V
DD
= 3.6V, V
IN
= 5.5V
T
A
= 25°C
V
OUT
= 1.8V
f
SW
= 300kHz
WURTH INDUCTOR:
744325120, L = 1.2µH, DCR = 1.8m
INFINEON MOSFETs:
BSC042N03MS G (UPPER/LOWER)
08901-002
Figure 2. ADP1882/ADP1883 Efficiency vs. Load Current
(V
OUT
= 1.8 V, 300 kHz)
GENERAL DESCRIPTION
The ADP1882/ADP1883 are versatile current-mode, synchronous
step-down controllers that provide superior transient response,
optimal stability, and current-limit protection by using a constant
on-time, pseudo-fixed frequency with a programmable current-
limit, current-control scheme. In addition, these devices offer
optimum performance at low duty cycles by using valley current-
mode control architecture. This allows the ADP1882/ADP1883
to drive all N-channel power stages to regulate output voltages
as low as 0.8 V.
The ADP1883 is the power saving mode (PSM) version of the
device and is capable of pulse skipping to maintain output
regulation while achieving improved system efficiency at light
loads (see the Power Saving Mode (PSM) Version (ADP1883)
section for more information).
Available in three frequency options (300 kHz, 600 kHz, and
1.0 MHz, plus the PSM option), the ADP1882/ADP1883 are
well suited for a wide range of applications. These ICs not only
operate from a 2.75 V to 5.5 V bias supply, but they also can
accept a power input as high as 20 V.
In addition, an internally fixed soft start period is included to limit
input in-rush current from the input supply during startup and
to provide reverse current protection during soft start for a pre-
charged output. The low-side current-sense, current-gain scheme
and integration of a boost diode, along with the PSM/forced
pulse-width modulation (PWM) option, reduce the external
part count and improve efficiency.
The ADP1882/ADP1883 operate over the −40°C to +125°C
junction temperature range and are available in a 10-lead MSOP.