MAX856ESA-T Maxim Integrated Products, MAX856ESA-T Datasheet

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MAX856ESA-T

Manufacturer Part Number
MAX856ESA-T
Description
LCD Drivers 3.3V-5V, High-Effici ency, Low IQ, DC-DC
Manufacturer
Maxim Integrated Products
Datasheet
The MAX856–MAX859 are high-efficiency, CMOS, step-
up, DC-DC switching regulators for small, low input volt-
age or battery-powered systems. The MAX856/MAX858
accept a positive input voltage between 0.8V and V
and convert it to a higher, pin-selectable output voltage of
3.3V or 5V. The MAX857/MAX859 adjustable versions
accept 0.8V to 6.0V input voltages and generate higher
adjustable output voltages in the 2.7V to 6.0V range.
Typical efficiencies are greater than 85%. Typical quies-
cent supply current is 25µA (1µA in shutdown).
The MAX856–MAX859 combine ultra-low quiescent supply
current and high efficiency to give maximum battery life. An
internal MOSFET power transistor permits high switching
frequencies. This benefit, combined with internally set peak
inductor current limits, permits the use of small, low-cost
inductors. The MAX856/MAX857 have a 500mA peak
inductor current limit. The MAX858/MAX859 have a 125mA
peak inductor current limit.
________________________Applications
19-0211; Rev 4; 5/96
For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800
__________Typical Operating Circuit
_______________General Description
LOW-BATTERY
3V/5V SELECT
DETECTOR
0.8V TO V
3.3V to 5V Step-Up Conversion
Palmtop Computers
Portable Data-Collection Equipment
Personal Data Communicators/Computers
Medical Instrumentation
2-Cell & 3-Cell Battery-Operated Equipment
Glucose Meters
ON/OFF
INPUT
INPUT
OUT
SHDN
3/5
LBI
REF
________________________________________________________________ Maxim Integrated Products
MAX856
GND
OUT
LBO
LX
1N5817
47 H
LOW-BATTERY
DETECTOR OUTPUT
3.3V/5V or Adjustable-Output,
3.3V AT 125mA
5V AT 100mA
OUTPUT
OR
68 F
Step-Up DC-DC Converters
OUT
♦ 0.8V to 6.0V Input Supply Voltage
♦ 0.8V Typ Start-Up Supply Voltage
♦ 85% Efficiency at 100mA
♦ 25µA Quiescent Current
♦ 1µA Shutdown Mode
♦ 125mA and 500mA Switch-Current Limits Permit
♦ Up to 500kHz Switching Frequency
♦ ±1.5% Reference Tolerance Over Temperature
♦ Low-Battery Detector (LBI/LBO)
♦ 8-Pin SO and µMAX Packages
Ordering Information continued at end of data sheet.
* Dice are tested at T
____________________________Features
__________________Pin Configuration
______________Ordering Information
MAX856CSA
MAX856CUA
MAX856C/D
MAX856ESA
MAX856MJA
MAX857CSA
MAX857CUA
MAX857C/D
MAX857ESA
MAX857MJA
Contact factory for availability.
Use of Low-Cost Inductors
TOP VIEW
PART
SHDN
SHDN
LBO
REF
LBO
REF
3/5
FB
A
-40°C to +85°C
-40°C to +85°C
-55°C to +125°C
-55°C to +125°C
1
2
3
4
1
2
3
4
TEMP. RANGE
= +25°C only.
0°C to +70°C
0°C to +70°C
0°C to +70°C
0°C to +70°C
0°C to +70°C
0°C to +70°C
SO/ MAX
SO/ MAX
MAX856
MAX858
MAX857
MAX859
8
7
6
5
8
7
6
5
PIN-PACKAGE
8 SO
8 µMAX
Dice*
8 SO
8 CERDIP
8 SO
8 µMAX
Dice*
8 SO
8 CERDIP
LX
GND
OUT
LBI
LX
GND
OUT
LBI
1

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MAX856ESA-T Summary of contents

Page 1

... Up to 500kHz Switching Frequency ♦ ±1.5% Reference Tolerance Over Temperature ♦ Low-Battery Detector (LBI/LBO) ♦ 8-Pin SO and µMAX Packages ______________Ordering Information PART MAX856CSA MAX856CUA MAX856C/D MAX856ESA MAX856MJA MAX857CSA MAX857CUA MAX857C/D MAX857ESA MAX857MJA Ordering Information continued at end of data sheet. * Dice are tested at T † ...

Page 2

Adjustable-Output, Step-Up DC-DC Converters ABSOLUTE MAXIMUM RATINGS Supply Voltage (OUT to GND) ...................................-0.3V, +7V Switch Voltage (LX to GND) .......................................-0.3V, +7V — — — – LBO to GND ....................................................-0.3V, +7V – – LBI, ...

Page 3

ELECTRICAL CHARACTERISTICS (continued) (Circuits of Figure 2.5V LOAD – — — — – – – Input Voltage Low — — — – – – ...

Page 4

Adjustable-Output, Step-Up DC-DC Converters _____________________________Typical Operating Characteristics (continued) (Circuits of Figure +25°C, unless otherwise noted.) A REFERENCE VOLTAGE vs. CURRENT 100 150 ...

Page 5

Operating Characteristics (continued) (Circuits of Figure +25°C, unless otherwise noted.) A MAX856/MAX857 LINE-TRANSIENT RESPONSE (5V MODE) V OUT 50mV/div 2ms/div MAX859 LINE-TRANSIENT RESPONSE V OUT 50mV/div 1V/div 1ms/div ...

Page 6

Adjustable-Output, Step-Up DC-DC Converters ______________________________________________________________Pin Description PIN NAME MAX856 MAX857 MAX858 MAX859 – — — — – – – 2 — — REF 4 4 LBO ...

Page 7

MINIMUM OFF-TIME ONE-SHOT SHDN 3/5* MAXIMUM ON-TIME TRIG ONE-SHOT ONE-SHOT MAX856–MAX859 LBO LBI *MAX856/MAX858 ONLY **MAX857/MAX859 ONLY Figure 1. Block Diagram _______________________________________________________________________________________ 3.3V/5V or Adjustable-Output, Step-Up DC-DC Converters TRIG Q ONE-SHOT F CURRENT-LIMIT COMPARATOR ERROR COMPARATOR ...

Page 8

Adjustable-Output, Step-Up DC-DC Converters Logic Inputs and Outputs The 3/5 input is internally diode clamped OUT, and should not be connected to signals outside this range. The SHDN input and LBO output (open- drain) are not clamped to ...

Page 9

Low-Battery Detection The MAX856 series contains an on-chip comparator for low-battery detection. If the voltage at LBI falls below the regulator’s internal reference voltage (1.25V), LBO (an open-drain output) sinks current to GND. The low- battery monitor’s threshold is set ...

Page 10

Adjustable-Output, Step-Up DC-DC Converters Table 1. Component Suppliers PRODUCTION INDUCTORS METHOD Surface Mount See Table 2 Miniature Sumida Through Hole RCH654-220 Renco RL 1284-22 Low-Cost Through Hole CoilCraft PCH-27-223 COMPANY PHONE AVX USA: (207) 282-5111 CoilCraft USA: (708) ...

Page 11

Table 2. Surface-Mount Inductor Information INDUCTANCE MANUFACTURER PART Sumida CDR105B-470 Sumida CDR74B-470 Sumida CD43-470 Sumida CD43-220 Murata-Erie LQH4N220 Murata-Erie LQH4N470 Murata-Erie LQH1N220 TDK NLC322522T-220K TDK NLC322522T-470K Coiltronics CTX20-1 Coilcraft DT1608-223 __Ordering Information (continued) PART TEMP. RANGE MAX858CSA 0°C to +70°C ...

Page 12

Adjustable-Output, Step-Up DC-DC Converters ________________________________________________________Package Information ______________________________________________________________________________________ C 0.101mm 0.004 in L 8-PIN MAX MICROMAX SMALL OUTLINE PACKAGE 0.101mm 0.004in Narrow ...

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