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Data Sheet
Wide Range Input, Dual/Two-Phase, DC-to-DC Synchronous Buck Controller
ADP1850
FEATURES
Wide range input: 2.75 V to 20 V Power stage input voltage: 1 V to 20 V Output voltage range: 0.6 V up to 90% VIN Output current to more than 25 A per channel Accurate current sharing between channels (interleaved) Programmable frequency: 200 kHz to 1.5 MHz 180° phase shift between channels for reduced input
capacitance ±0.85% reference voltage accuracy from −40°C to +85°C Integrated boost diodes Power saving mode (PSM) at light loads Accurate power good with internal pull-up resistor Accurate voltage tracking capability Independent channel precision enable Overvoltage and overcurrent limit protection Externally programmable soft start, slope compensation and
current sense gain Synchronization input Thermal overload protection Input undervoltage lockout (UVLO) Available in 32-lead 5 mm × 5 mm LFCSP
APPLICATIONS
High current single and dual output intermediate bus and point of load converters requiring sequencing and tracking capability, including converters for: Point-of-load power supplies Telecom base station and networking Consumer Industrial and instrumentation Healthcare and medical
GENERAL DESCRIPTION
The ADP1850 is a configurable dual output or two-phase, single output dc-to-dc synchronous buck controller capable of running from commonly used 3.3 V to 12 V (up to 20 V) voltage inputs. The device operates in current mode for improved transient response and uses valley current sensing for enhanced noise immunity.
The architecture enables accurate current sharing between interleaved phases for high current outputs.
The ADP1850 is ideal in system applications requiring multiple output voltages: the ADP1850 includes a synchronization feature to eliminate beat frequencies between switching devices; provides accurate tracking capability between supplies and includes precision enable for simple, robust sequencing.
Rev. C
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09440-001
TYPICAL OPERATION CIRCUIT
VIN RRAMP1
RAMP1 VIN
ADP1850
EN1
DH1
EN2
BST1
VDL
M1 L1
VCCO TRK1 TRK2
SW1 ILIM1
FB1
DL1
R11
M2 R12
PGOOD1
RCSG1
PGOOD2 PGND1
HI LO
SYNC
FREQ
RRAMP2 RAMP2
VIN
COMP1 COMP2
SS1 SS2 AGND
DH2 BST2 SW2 ILIM2
FB2
DL2
PGND2
M3 L2
R21
RCSG2
M4 R22
VOUT1 VOUT2
Figure 1. Single Phase Circuit
The ADP1850 provides high speed, high peak current drive capability with dead-time optimization to enable energy efficient power conversion. For low load operation, the device can be configured to operate in power saving mode (PSM) by skipping pulses and reducing switching losses to improve the energy efficiency at light load and standby conditions.
The accurate current limit (±6%) allows the power architect to design within a narrower range of tolerances and can reduce overall converter size and cost.
The ADP1850 provides a configurable architecture capable of wide range input operation to provide the designer with maximum re-use opportunities and improved time to market. Additional flexibility is provided by external programmability of loop compensation, soft start, frequency setting, power saving mode, current limit and current sense gain can all be programmed using external components.
The ADP1850 includes a high level of integration in a small size package. The start-up linear regulator and the boot-strap diode for the high side drive are included. Protection features include: undervoltage lock-out, overvoltage, overcurrent/short-circuit and over temperature. The ADP1850 is available in a compact 32-lead LFCSP 5 mm × 5 mm thermally enhanced package.
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ADP1850
TABLE OF CONTENTS
Features .............................................................................................. 1 Applications....................................................................................... 1 General Description ......................................................................... 1 Typical Operation Circuit................................................................ 1 Revision History ............................................................................... 2 Specifications..................................................................................... 3 Absolute Maximum Ratings............................................................ 5
ESD Caution........