MAX8505EEE+ Maxim Integrated Products, MAX8505EEE+ Datasheet

IC REG STP DWN 3A 16-QSOP

MAX8505EEE+

Manufacturer Part Number
MAX8505EEE+
Description
IC REG STP DWN 3A 16-QSOP
Manufacturer
Maxim Integrated Products
Type
Step-Down (Buck)r
Datasheet

Specifications of MAX8505EEE+

Internal Switch(s)
Yes
Synchronous Rectifier
Yes
Number Of Outputs
1
Voltage - Output
0.8 ~ 4.68 V
Current - Output
3A
Frequency - Switching
500kHz, 1MHz
Voltage - Input
2.6 ~ 5.5 V
Operating Temperature
-40°C ~ 85°C
Mounting Type
Surface Mount
Package / Case
16-QSOP
Power - Output
1W
Input Voltage
2.6 V to 5.5 V
Supply Current
6 mA
Maximum Operating Temperature
+ 85 C
Minimum Operating Temperature
- 40 C
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
The MAX8505 step-down regulator operates from a 2.6V
to 5.5V input and generates an adjustable output voltage
from 0.8V to 0.85
bias supply, the input voltage can be as low as 2.25V.
The MAX8505 integrates power MOSFETs and
operates at 1MHz/500kHz switching frequency to
provide a compact design. Current-mode pulse-width-
modulated (PWM) control simplifies compensation with
ceramic or polymer output capacitors and provides
excellent transient response.
The MAX8505 features 1% accurate output over load,
line, and temperature variations. Adjustable soft-start is
achieved with an external capacitor. During the
soft-start period, the voltage-regulation loop is active.
This limits the voltage dip when the active devices,
such as microprocessors or ASICs connected to the
MAX8505’s output, apply a sudden load current step
upon passing their undervoltage thresholds.
The MAX8505 features current-limit, short-circuit, and
thermal-overload protection and enables a rugged
design. Open-drain power-OK (POK) monitors the
output voltage.
19-2992; Rev 1; 9/10
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.
µP/ASIC/DSP/FPGA Core and I/O Supplies
Chipset Supplies
Server, RAID, and Storage Systems
Network and Telecom Equipment
TOP VIEW
POK
BST
V
CTL
LX
LX
CC
IN
IN

________________________________________________________________ Maxim Integrated Products
3A, 1MHz, 1% Accurate, Internal Switch
VIN at up to 3A. With a 2.6V to 5.5V
1
2
6
3
4
5
7
8
General Description
MAX8505
QSOP
Step-Down Regulator with Power-OK
Pin Configuration
Applications
16
15
14
13
12
11
10
9
LX
PGND
LX
PGND
GND
REF
FB
COMP
o Saves Space—4.9mm x 6mm Footprint, 1µH
o Input Voltage Range
o 0.8V to 0.85
o Ceramic or Polymer Capacitors
o ±1% Output Accuracy Over Load, Line, and
o Fast Transient Response
o Adjustable Soft-Start
o In-Regulation Soft-Start Limits Output-Voltage
o POK Monitors Output Voltage
+ Denotes a lead(Pb)-free/RoHS-compliant package.
Functional Diagram appears at end of data sheet.
MAX8505EEE+
2.6V TO 5.5V
Inductor, 47µF Ceramic Output Capacitor
Temperature
Dips at Power-On
2.6V to 5.5V
Down to 2.25V with Bias Supply
INPUT
POWER-OK
ENABLE
PART

Typical Operating Circuit
V
IN
IN
V
CTL
POK
CC
, 3A Output
MAX8505
Ordering Information
-40°C to +85°C
TEMP RANGE
BST
GND
COMP
PGND
REF
LX
FB
PIN-PACKAGE
16 QSOP
Features
OUTPUT
0.8V TO
0.85 x V
3A
IN
1

Related parts for MAX8505EEE+

MAX8505EEE+ Summary of contents

Page 1

... Ceramic or Polymer Capacitors o ±1% Output Accuracy Over Load, Line, and Temperature o Fast Transient Response o Adjustable Soft-Start o In-Regulation Soft-Start Limits Output-Voltage Dips at Power-On o POK Monitors Output Voltage PART Applications MAX8505EEE+ + Denotes a lead(Pb)-free/RoHS-compliant package. Functional Diagram appears at end of data sheet INPUT 2.6V TO 5.5V 15 PGND 14 ...

Page 2

Accurate, Internal Switch Step-Down Regulator with Power-OK ABSOLUTE MAXIMUM RATINGS CTL, FB, IN GND .........................................-0.3V to +6V CC COMP, REF, POK to GND ..........................-0. BST to LX..................................................................-0.3V to +6V PGND to GND .......................................................-0.3V ...

Page 3

Accurate, Internal Switch Step-Down Regulator with Power-OK ELECTRICAL CHARACTERISTICS (continued +3.3V 0.8V CTL FB PARAMETER SYMBOL COMP Clamp Voltage, Low COMP Clamp Voltage, High COMP Shutdown ...

Page 4

Accurate, Internal Switch Step-Down Regulator with Power-OK ELECTRICAL CHARACTERISTICS ( +3.3V 0.8V CTL FB PARAMETER SYMBOL IN AND Voltage Range V Voltage Range CC ...

Page 5

Accurate, Internal Switch Step-Down Regulator with Power-OK ELECTRICAL CHARACTERISTICS (continued +3.3V 0.8V CTL FB PARAMETER SYMBOL LX Maximum Duty Cycle LX Minimum Duty Cycle SLOPE COMPENSATION ...

Page 6

Accurate, Internal Switch Step-Down Regulator with Power-OK (Typical values are CTL EFFICIENCY vs. OUTPUT CURRENT ( 5V 1MHz 100 A 90 ...

Page 7

Accurate, Internal Switch Step-Down Regulator with Power-OK (Typical values are CTL SHUTDOWN SUPPLY CURRENT vs. INPUT VOLTAGE 0.4 0.3 0.2 0.1 0 2.5 3.0 3.5 4.0 INPUT VOLTAGE (V) ...

Page 8

Accurate, Internal Switch Step-Down Regulator with Power-OK (Typical values are CTL TRANSIENT RESPONSE (V = 3.3V 1.2V) IN OUT MAX8505 toc14 40µs/div SOFT-START/SHUTDOWN WAVEFORM (V = 3.3V, ...

Page 9

Accurate, Internal Switch Step-Down Regulator with Power-OK PIN NAME Inductor Connection. Connect an inductor between these pins and the regulator output. All LX pins must connected together externally. Connect a 3300pF ...

Page 10

Accurate, Internal Switch Step-Down Regulator with Power-OK The MAX8505 offers both high-side and low-side current limits. The high-side current limit monitors the inductor peak current and the low-side current limit monitors the inductor valley current. Current-limit thresh- ...

Page 11

Accurate, Internal Switch Step-Down Regulator with Power-OK Output Voltage Selection The output voltage of the MAX8505 can be adjusted from 0.8V to 85% of the input voltage at 500kHz 80% of the input voltage ...

Page 12

Accurate, Internal Switch Step-Down Regulator with Power-OK Input Capacitor Design The input capacitor reduces the current peaks drawn from the input power supply and reduces switching noise in the IC. The impedance of the input capacitor at ...

Page 13

Accurate, Internal Switch Step-Down Regulator with Power-OK Applications Information PC Board Layout Considerations Careful PC board layout is critical to achieve clean and stable operation. The switching power stage requires particular attention. Follow these guidelines for good ...

Page 14

Accurate, Internal Switch Step-Down Regulator with Power-OK MAX8505 25µA REF 25µA Chip Information PROCESS: BiCMOS 14 ______________________________________________________________________________________ REFERENCE 1.25V FB UVLO GND GND COMP For the latest package outline information and land patterns www.maxim-ic.com/packages. Note ...

Page 15

... Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time. Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 ____________________ 15 © 2010 Maxim Integrated Products ...

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