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PDF ADP1877 Data sheet ( Hoja de datos )
| Número de pieza | ADP1877 | |
| Descripción | Dual Output Synchronous Buck PWM Controller | |
| Fabricantes | Analog Devices | |
| Logotipo |  |
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Hay una vista previa y un enlace de descarga de ADP1877 (archivo pdf) en la parte inferior de esta página. Total 30 Páginas | ||
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Dual Output SynchronouwswwB.DautacShkeetP4U.WcomM
Controller With Tracking
ADP1877
FEATURES
Input voltage range: 2.75 V to 14.5 V
Output voltage range: 0.6 V to 0.9 V
Maximum output current 20 A or higher per channel
Programmable frequency: 200 kHz to 1.5 MHz
Flexmode® architecture with integrated drivers
180° phase shift minimizes input ripple current and required
input capacitance
±0.85% output voltage accuracy 0°C to 70°C
Integrated boost diodes
Pulse skip high efficiency mode under light load
Power good with internal pull-up resistor
Overvoltage and overcurrent limit protection
Thermal overload protection
Input undervoltage lockout (UVLO)
Externally adjustable soft start, slope compensation and
current sense gain
Independent precision enable inputs
Synchronization input
Suitable for any output capacitors
Available in 32-lead 5 mm × 5 mm LFCSP
APPLICATIONS
Set top boxes
Printers
Communication infrastructure
Distributor power dc systems
Industrial and instrumentation
GENERAL DESCRIPTION
The ADP1877 is a Flexmode® (proprietary architecture of
Analog Devices, Inc.), dual-channel, step-down switching
controller with integrated drivers that drive N-channel
synchronous power MOSFETs. The two PWM outputs are
phase shifted 180°, which reduces the input RMS current, thus
minimizing required input capacitance.
The boost diodes are built into the ADP1877, thus lowering the
overall system cost and component count. The ADP1877 can
be set to operate in pulse skip high efficiency mode under light
load or in PWM continuous conduction mode.
The ADP1877 includes externally adjustable soft start, output
overvoltage protection, externally adjustable current limit,
power good, and a programmable oscillator frequency that
ranges from 200 kHz to 1.5 MHz. The ADP1877 provides an
output voltage accuracy of ±0.85% from 0°C to 85°C and ±1.5%
from −40°C to 125°C in junction temperature. This part can be
powered from a 2.75 V to 14.5 V supply, operates over the
−40oC to +125oC junction temperature range, and is available
in a 32-lead 5 mm × 5 mm LFCSP package.
RAMP1
VIN
RAMP1 VIN
EN1
EN2
VDL
VCCO
PGOOD1
PGOOD2
TRK1
TRK2
SYNC
FREQ
DH1
BST1
SW1
ILIM1
FB1
DL1
PGND1
RAMP2
RCSG1
RRAMP2
M1
L1
RTOP1
VOUT1
M2
RBOT1
VIN
COMP1
COMP2
SS1
SS2
AGND
DH2
BST2
SW2
ILIM2
FB2
DL2
PGND2
M3
L2
RTOP2
VOUT2
M4
RCSG2
RBOT2
Figure 1. Typical Operation Circuit
1.0
0.9 VO = 3.3V PSM
0.8 VO = 1.8V PSM
0.7
0.6
VO = 3.3V PWM
0.5
VO = 1.8V PWM
0.4
0.3
0.2
0.1
0
0.01
VIN = 12V, 300kHz
0.1 1 10 100
LOAD (A)
Figure 2. Efficiency Plot of Figure 42, 20 A Output
Rev. 0
Information furnished by Analog Devices is believed to be accurate and reliable. However, no
responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or
other rights of third parties that may result from its use. Specifications subject to change without
notice. No license is granted by implication or otherwise under any patent or patent rights of
Analog Devices. Trademarks and registered trademarks are the property of their respective
owners.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781.329.4700
www.analog.com
Fax: 781.461.3113
©2009 Analog Devices, Inc. All rights reserved.
1 page  
ADP1877www.DataSheet4U.com
Parameter
PGOOD
PGOOD Pull-up Resistor
PGOOD Delay
Overvoltage or Undervoltage
Minimum Duration
ILIM1, ILIM2 Threshold Voltage1
ILIM1, ILIM2 Output Current
Current Sense Blanking Period
INTEGRATED RECTIFIER
(BOOST DIODE) RESISTANCE
ZERO CURRENT CROSS OFFSET
(SW TO PGND)1
Symbol
RPGOOD
Conditions
Min
Internal pull-up resistor to VCCO
This is the minimum duration required to trip
the PGOOD signal.
Relative to PGND
ILIM = PGND
After DL goes high, current limit is not sensed
during this period.
At 20 mA forward current
−5
40
In pulse skip mode only; fOSC = 600 kHz
0
Typ Max Units
12.5 kΩ
12 μs
12 μs
0 +5
50 60
100
16
24
mV
μA
ns
Ω
mV
1 Guaranteed by design.
2 Connect VIN to VCCO when VIN < 5.5 V. For applications with VIN < 5.5 V and VIN not connected to VCCO, keep in mind that VCCO = VIN − VDROPOUT. VCCO must be ≥
2.75 V for proper operation.
Rev. 0 | Page 5 of 32
5 Page 
6
5
4
3
2
1
0
0123456
VIN (V)
Figure 11. VCCO vs. VIN
SW1
1
SW2
2
3
SYNC 600kHz
CH1 10V
CH3 5V
CH2 10V
M1µs
A CH1 5.60V
Figure 12. An Example of Synchronization, fSW = 600 kHz
OUTPUT RESPONSE
1
5A TO 10A STEP LOAD
4
VVIONU=T
12V
= 1.8V
CH1 50mV CH4 5A Ω
M200µs
A CH4 8.10A
Figure 13. Step Load Transient of Figure 42, 5 A to 10 A
ADP1877www.DataSheet4U.com
OUTPUT RESPONSE
1
OUTPUT STEP LOAD 0.5A TO 0.8A
4
VVIONU=T
3V
= 1.8V
CH1 20mV
M100µs
CH4 500mA Ω
A CH4 750mA
Figure 14. Step Load Transient of Figure 44
1
2
VOUT1
DH1
DL1
3 IL1
4
VIN = 12V
VOUT = 1.8V
OUTPUT PRECHARGED TO 1V
CH1 5V
CH3 1V
CH2 5V
CH4 1A Ω
M1ms
A CH1 2.4V
Figure 15. Soft Start into Precharged Output
EN IS TIED TO VIN
CSS = 100nF
VIN POWER SUPPLY
VOUT (CH2)
1
SS
SW
2
4
3
CH1 5V
CH3 10V
CH2 1V
CH4 500mV
M2ms
A CH2
Figure 16. Power-On Sequence
2.42V
Rev. 0 | Page 11 of 32
11 Page | ||
| Páginas | Total 30 Páginas | |
| PDF Descargar | [ Datasheet ADP1877.PDF ] | |
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