MAX887HESA+ Maxim Integrated Products, MAX887HESA+ Datasheet

IC DC-DC CONV LN 8-SOIC

MAX887HESA+

Manufacturer Part Number
MAX887HESA+
Description
IC DC-DC CONV LN 8-SOIC
Manufacturer
Maxim Integrated Products
Type
Step-Down (Buck)r
Datasheet

Specifications of MAX887HESA+

Internal Switch(s)
Yes
Synchronous Rectifier
Yes
Number Of Outputs
1
Voltage - Output
1.25 ~ 10 V
Current - Output
600mA
Frequency - Switching
300kHz
Voltage - Input
3.5 ~ 11 V
Operating Temperature
-40°C ~ 85°C
Mounting Type
Surface Mount
Package / Case
8-SOIC (3.9mm Width)
Power - Output
471mW
Output Voltage
1.25 V to 10.5 V
Output Current
600 mA
Input Voltage
3.5 V to 11 V
Supply Current
2.7 mA
Switching Frequency
300 KHz
Maximum Operating Temperature
+ 85 C
Minimum Operating Temperature
- 40 C
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
The MAX887 high-efficiency, step-down DC-DC con-
verter provides an adjustable output from 1.25V to
10.5V. It accepts inputs from 3.5V to 11V and delivers
600mA. Operation to 100% duty cycle minimizes
dropout voltage (300mV typ at 500mA). Synchronous
rectification reduces output rectifier losses, resulting in
efficiency as high as 95%.
Fixed-frequency pulse-width modulation (PWM)
reduces noise in sensitive communications applica-
tions. Using a high-frequency internal oscillator allows
tiny surface-mount components to reduce PC board
area, and eliminates audio-frequency interference. A
SYNC input allows synchronization to an external clock
to avoid interference with sensitive RF and data-
acquisition circuits.
The MAX887 features current-mode operation for supe-
rior load/line-transient response. Cycle-by-cycle current
limiting protects the internal MOSFET and rectifier. A
low-current (2.5µA typ) shutdown mode conserves bat-
tery life.
________________________Applications
19-1142 Rev 0; 9/96
For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800
__________Typical Operating Circuit
_______________General Description
47 F
V
OFF
IN
2.2 F
= 3.5V to 11V
ON
Portable Instruments
Cellular Phones and Radios
Personal Communicators
Distributed Power Systems
Computer Peripherals
0.33 F
0.047 F
V+
REF
SHDN
SYNC
VL
________________________________________________________________ Maxim Integrated Products
MAX887
GND
V
OUT
= 1.25V (R1/R2 + 1)
LX
FB
Step-Down, PWM DC-DC Converter
33 H
100k
165k
R2
R1
C1
100pF
100% Duty Cycle, Low-Noise,
V
OUT
= 3.3V
47 F
*
____________________________Features
Contact factory for availability. Dice are tested at T
______________Ordering Information
MAX887HC/D
MAX887HESA
__________________Pin Configuration
95% Efficiency
600mA Output Current
Cycle-by-Cycle Current Limiting
Low-Dropout, 100% Duty-Cycle Operation,
300mV at 500mA
Internal 0.6Ω (typ) MOSFET
Internal Synchronous Rectifier
High-Frequency Current-Mode PWM
External SYNC or Internal 300kHz Oscillator
Guaranteed 260kHz to 340kHz Internal Oscillator
Frequency Limits
2.5µA Shutdown Mode
TOP VIEW
PART
SHDN
REF
FB
VL
-40°C to +85°C
TEMP. RANGE
1
2
3
4
0°C to +70°C
MAX887
SO
8
7
6
5
Dice*
8 SO
PIN-PACKAGE
V+
LX
SYNC
GND
A
= +25°C.
1

Related parts for MAX887HESA+

MAX887HESA+ Summary of contents

Page 1

... FB VL REF GND 2.2 F 0.047 1.25V (R1/ OUT ________________________________________________________________ Maxim Integrated Products For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800 100% Duty Cycle, Low-Noise, ____________________________Features 95% Efficiency 600mA Output Current Cycle-by-Cycle Current Limiting Low-Dropout, 100% Duty-Cycle Operation, 300mV at 500mA Internal 0.6Ω (typ) MOSFET ...

Page 2

Duty Cycle, Low-Noise, Step-Down, PWM DC-DC Converter ABSOLUTE MAXIMUM RATINGS REF, FB, SYNC GND..................................... -0. GND ............................................................. -0.3V to +12V SHDN GND ....................................... -0.3V to (V+ + 0.3V) PGND to GND ...

Page 3

Step-Down, PWM DC-DC Converter ELECTRICAL CHARACTERISTICS (V+ = +7V, PGND = GND = 0V, SHDN = V+, (T PARAMETER SYMBOL Supply Range Quiescent Supply Current I (PWM Mode) Quiescent Supply Current (PFM Mode) Shutdown Supply Current I V+, SHDN Output ...

Page 4

Duty Cycle, Low-Noise, Step-Down, PWM DC-DC Converter ____________________________Typical Operating Characteristics (continued) (Circuit of Figure +25°C, unless otherwise noted.) A EFFICIENCY vs. OUTPUT CURRENT 100 ...

Page 5

Step-Down, PWM DC-DC Converter ____________________________Typical Operating Characteristics (continued) (Circuit of Figure +25°C, unless otherwise noted.) A HEAVY-LOAD, PWM-MODE SWITCHING WAVEFORMS 0mA 1 s/div 3.3V, LOAD = 500mA IN OUT ...

Page 6

Duty Cycle, Low-Noise, Step-Down, PWM DC-DC Converter _____________________________Typical Operating Characteristics (continued) (Circuit of Figure +25°C, unless otherwise noted.) A LOAD-TRANSIENT RESPONSE s/div 3.3V, IN OUT LOAD = ...

Page 7

Step-Down, PWM DC-DC Converter ______________________________________________________________Pin Description PIN NAME SHDN Shutdown, Active-Low, Logic-Level Input. Connect SHDN to V+ for normal operation Feedback Input. Connect resistor voltage divider between the output and GND. 3 REF Reference ...

Page 8

Duty Cycle, Low-Noise, Step-Down, PWM DC-DC Converter _______________Detailed Description The MAX887 is a step-down, pulse-width modulation (PWM) DC-DC converter that provides an adjustable output from 1.25V to 10.5V. It accepts inputs from 3.5V to 11V and delivers up to ...

Page 9

Step-Down, PWM DC-DC Converter backward through the inductor, from the output filter capacitor to GND, or through the switch and synchro- nous rectifier to GND. During PWM operation, the NEGLIM threshold adjusts to permit small amounts of reverse current to ...

Page 10

Duty Cycle, Low-Noise, Step-Down, PWM DC-DC Converter when to turn off this synchronous rectifier. A fourth comparator (ILIM) is used at the P-channel MOSFET switch for overcurrent detection. This protects the sys- tem, external components, and internal MOSFETs under ...

Page 11

Step-Down, PWM DC-DC Converter Bypass V+ to GND using a 0.33µF capacitor. Also bypass VL to GND with a 2.2µF capacitor, and VREF to GND using a 0.047µF capacitor. These capacitors should be placed within 0.2in (5mm) of their respective ...

Page 12

Duty Cycle, Low-Noise, Step-Down, PWM DC-DC Converter ________________________________________________________Package Information ______________________________________________________________________________________ 0.101mm 0.004in Narrow SO SMALL-OUTLINE H PACKAGE (0.150 in.) INCHES MILLIMETERS DIM MIN MAX MIN A 0.053 0.069 1.35 A1 ...

Related keywords