Rainbow Electronics MAX859 User Manual

19-0211; Rev 4; 5/96
EVALUATION KIT MANUAL
FOLLOWS DATA SHEET
3.3V/5V or Adjustable-Output, Step-Up DC-DC Converters
_______________General Description
The MAX856–MAX859 are high-efficiency, CMOS, step­up, DC-DC switching regulators for small, low input volt­age or battery-powered systems. The MAX856/MAX858 accept a positive input voltage between 0.8V and V
OUT
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 quies­cent 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
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
__________Typical Operating Circuit
____________________________Features
0.8V to 6.0V Input Supply Voltage0.8V Typ Start-Up Supply Voltage85% Efficiency at 100mA25µA Quiescent Current1µA Shutdown Mode125mA and 500mA Switch-Current Limits Permit
Use of Low-Cost Inductors
Up to 500kHz Switching Frequency±1.5% Reference Tolerance Over TemperatureLow-Battery Detector (LBI/LBO)8-Pin SO and µMAX Packages
______________Ordering Information
PART TEMP. RANGE PIN-PACKAGE
MAX856CSA
MAX856CUA 0°C to +70°C 8 µMAX MAX856C/D 0°C to +70°C Dice* MAX856ESA -40°C to +85°C 8 SO MAX856MJA -55°C to +125°C 8 CERDIP MAX857CSA MAX857CUA 0°C to +70°C 8 µMAX MAX857C/D MAX857ESA -40°C to +85°C 8 SO MAX857MJA -55°C to +125°C 8 CERDIP
Ordering Information continued at end of data sheet.
* Dice are tested at TA= +25°C only.
Contact factory for availability.
0°C to +70°C 8 SO
0°C to +70°C 8 SO
0°C to +70°C Dice*
MAX856–MAX859
INPUT
0.8V TO V
ON/OFF
3V/5V SELECT
LOW-BATTERY
DETECTOR
INPUT
OUT
OUTPUT
5V AT 100mA
SHDN
47µH
LX
1N5817
OR
3.3V AT 125mA
68µF
MAX856
3/5
LBI
REF
________________________________________________________________
GND
OUT
LBO
LOW-BATTERY DETECTOR OUTPUT
__________________Pin Configuration
TOP VIEW
SHDN
3/5
REF
LBO
SHDN
REF
LBO
FB
1 2
MAX856
3
MAX858
4
SO/µMAX
1 2
MAX857
3
MAX859
4
SO/µMAX
Maxim Integrated Products
8
LX
7
GND
6
OUT
5
LBI
8
LX
7
GND
6
OUT
5
LBI
1
For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800
3.3V/5V or 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
S—H—D—N–, LBO to GND....................................................-0.3V, +7V
LBI, REF, 3/–5–, FB to GND .........................-0.3V, (V
Reference Current (I Continuous Power Dissipation (T
SO (derate 5.88mW/°C above +70°C) .........................471mW
µMAX (derate 4.1mW/°C above +70°C) ......................330mW
CERDIP (derate 8.00mW/°C above +70°C) .................640mW
Note 1: Reverse battery current is measured from the
connected backwards. A reverse current of 750mA will not exceed the SO or CERDIP package dissipation limits but, if left for an extended time (more than ten minutes), may degrade performance.
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.
) ..................................................2.5mA
REF
= +70°C)
A
+ 0.3V)
OUT
Typical Operating Circuit’s
Reverse Battery Current (T Operating Temperature Ranges
MAX85_C_ _ ......................................................0°C to +70°C
MAX85_E_ _ ....................................................-40°C to +85°C
MAX85_MJA .................................................-55°C to +125°C
Junction Temperature .....................................................+150°C
Storage Temperature Range ............................-65°C to +160°C
Lead Temperature (soldering, 10sec) ............................+300°C
battery input terminal to GND when the battery is
+45°C, Note 1) .................750mA
A
MAX856–MAX859
ELECTRICAL CHARACTERISTICS
(Circuits of Figure 2, VIN= 2.5V, I
= 0mA, TA= T
LOAD
MIN
to T
, unless otherwise noted. Typical values are at TA= +25°C.)
MAX
Output Voltage
Minimum Start-Up Supply Voltage
Quiescent Supply Current in
3.3V Mode (Note 2)
Shutdown Quiescent Current (Note 2)
Peak Inductor Current Limit
CONDITIONS
MAX856, 3/–5–= 0V, 0mA I MAX856, 3/–5–= 3V, 0mA I
2V VIN≤ 3V
I
= 0mA
LOAD
I
= 0mA, 3/–5–= 3V, LBI = 1.5V, V
LOAD
(FB = 1.5V, MAX857/MAX859 only)
Output set for 3.3V, measured at VINin Figure 2, R3 omitted.
S—H—D—N–= 0V, 3/–5–= 3V, LBI = 1.5V, V (FB = 1.5V, MAX857/MAX859 only)
MAX856/MAX857 MAX858/MAX859 No REF load 3/–5–= 3V, -20µA REF load 250µA, C With falling edge
I
= 2mA
SINK
LBO = 5V
MAX857, V MAX858, 3/–5–= 0V, 0mA I MAX858, 3/–5–= 3V, 0mA I MAX859, V
= 5V, 0mA I
OUT
= 5V, 0mA I
OUT
OUT
OUT
REF
= 3.47V,
= 3.47V,
LOAD LOAD LOAD LOAD LOAD LOAD
= 0.22µF
100mA150mA100mA25mA35mA25mA
MAX85_C MAX85_E/M
4.80 5.0 5.20
3.17 3.3 3.43
4.80 5.0 5.20
4.80 5.0 5.20
3.17 3.3 3.43
4.80 5.0 5.20
1
15 500 125
UNITSMIN TYP MAXPARAMETER
V
V0.8 1.8 V0.8Minimum Operating Voltage
µA25 60
µA60No Load Battery Current
µA
mA
V1.23 1.25 1.27Reference Voltage
%0.8 2.0Reference-Voltage Regulation
V1.22 1.25 1.28LBI Input Threshold
mV25LBI Input Hysteresis
V0.4LBO Output Voltage Low
µA1LBO Output Leakage Current
2 _______________________________________________________________________________________
3.3V/5V or Adjustable-Output, Step-Up DC-DC Converters
ELECTRICAL CHARACTERISTICS (continued)
(Circuits of Figure 2, VIN= 2.5V, I
–S—H—D—N–
, 3/–5–Input Voltage Low S—H—D—N–, 3/–5–Input Voltage High 1.6 V S—H—D—N–, 3/–5–, FB, LBI Input Current LBI = 1.5V, FB = 1.5V, –S—H—D—N–= 0V or 3V, 3/–5–= 0V or 3V ±100 nA FB Voltage MAX857/MAX859 1.22 1.25 1.28 V Output Voltage Range MAX857/MAX859, I
Note 2: Supply current from the 3.3V output is measured with an ammeter between the 3.3V output and OUT pin. This current
correlates directly with actual battery supply current, but is reduced in value according to the step-up ratio and efficiency. V
= 3.47V to keep the internal switch open when measuring the current into the device.
Note 3: Minimum value is production tested. Maximum value is guaranteed by design and is not production tested.
OUT
= 0mA, TA= T
LOAD
to T
MIN
LOAD
, unless otherwise noted. Typical values are at TA= +25°C.)
MAX
= 0mA (Note 3) 2.7 6.0 V
0.4 V
__________________________________________Typical Operating Characteristics
(Circuits of Figure 2, TA= +25°C, unless otherwise noted.)
MAX858/MAX859
EFFICIENCY vs. OUTPUT CURRENT
V
100
90 80 70 60 50 40
EFFICIENCY (%)
30 20 10
0
0.1
0.010.001 LOAD CURRENT (mA)
OUT
= 3.3V
VIN = 1.5V
1
VIN = 2.5V
VIN = 2.0V
10
100 1000
MAX856-01
100
90 80 70 60 50 40
EFFICIENCY (%)
30 20 10
0
MAX858/MAX859
EFFICIENCY vs. OUTPUT CURRENT
V
= 5V
OUT
VIN = 3.3V
VIN = 2.5V
1
10
100 1000
0.1
0.010.001 LOAD CURRENT (mA)
VIN = 1.5V
MAX856-02
MAX856–MAX859
MAX856/MAX857
EFFICIENCY vs. OUTPUT CURRENT
100
90 80 70 60 50 40
EFFICIENCY (%)
30 20 10
0
0.1
0.010.001 LOAD CURRENT (mA)
V
OUT
= 5V
VIN = 2.0V
1
VIN = 3.3V
10
VIN = 1.5V
100 1000
MAX856-03
100
90 80 70 60 50 40
EFFICIENCY (%)
30 20 10
0
MAX856/MAX857
EFFICIENCY vs. OUTPUT CURRENT
V
= 3.3V
OUT
VIN = 2.5V
VIN = 1.5V
VIN = 2.0V
0.1
0.010.001 LOAD CURRENT (mA)
1
10
100 1000
MAX856-04
_______________________________________________________________________________________
3
3.3V/5V or Adjustable-Output, Step-Up DC-DC Converters
_____________________________Typical Operating Characteristics (continued)
(Circuits of Figure 2, TA= +25°C, unless otherwise noted.)
REFERENCE VOLTAGE vs. CURRENT
10
9 8 7 6 5 4 3
LOAD REGULATION (mV)
REF
2
V
MAX856–MAX859
1 0
0
50 150 250
REFERENCE LOAD CURRENT (µA)
1.6
1.4
1.2
1.0
0.8
0.6
0.4
QUIESCENT CURRENT (mA)
0.2 TA = -40°C
0
1.5
2.0
1.0
0.9
0.8
0.7
0.6
0.5
0.4
0.3
SHUTDOWN CURRENT (µA)
0.2
TA = -40°C
0.1
0
2.0
1.5
100 200
QUIESCENT CURRENT
vs. INPUT VOLTAGE
SEE NOTE 2 IN THE ELECTRICAL CHARACTERISTICS
2.5 3.0
INPUT VOLTAGE (V)
SHUTDOWN CURRENT
vs. INPUT VOLTAGE
TA = +85°C
TA = +25°C
2.5 3.0
INPUT VOLTAGE (V)
TA = +85°C
3.5
3.5
4.0
4.0
400 350
MAX856-05
300 250 200
150 100
QUIESCENT CURRENT (µA)
50
0
1.5
1.15
MAX856-10
1.10
1.05
1.00
0.95
0.90
0.85
START-UP INPUT VOLTAGE (V)
0.80
0.75
0.1 10
400
MAX856-11
350 300 250 200 150
LOAD CURRENT (mA)
100
50
0
1.0
MAX856/MAX857
NO LOAD BATTERY CURRENT
vs. INPUT VOLTAGE
TA = +85°C
INCLUDES ALL EXTERNAL COMPONENT LEAKAGES. CAPACITOR LEAKAGE DOMINATES AT T CAPS ARE SPRAGUE 595 D
TA = +25°C
TA = -40°C
MINIMUM START-UP INPUT VOLTAGE
2.5 3.0
2.0 INPUT VOLTAGE (V)
MAX856/MAX857
vs. LOAD CURRENT
1 100
LOAD CURRENT (mA)
MAX856/MAX857
MAXIMUM OUTPUT CURRENT
vs. INPUT VOLTAGE
V
= 3.3V
OUT
2.01.5 2.5
INPUT VOLTAGE (V)
V
V
= 5.0V
OUT
3.0 3.5 4.0
OUT
= +85°C.
A
3.5
= 5V
V
OUT
= 3.3V
1.6
MAX856-08
1.4
1.2
1.0
0.8
0.6
0.4
QUIESCENT CURRENT (mA)
0.2
4.0
0
1.4
MAX856-06
1.3
1.2
1.1
1.0
START-UP INPUT VOLTAGE (V)
0.9
0.8
100
90
MAX856-13
80 70 60 50 40 30
LOAD CURRENT (mA)
20 10
0
1.5
0.1 10
1.0
4 _______________________________________________________________________________________
MAX858/MAX859
NO LOAD BATTERY CURRENT
vs. INPUT VOLTAGE
= +85°C
T
A
= +25°C
T
A
= -40°C
T
A
MINIMUM START-UP INPUT VOLTAGE
V
OUT
INCLUDES ALL EXTERNAL COMPONENT LEAKAGES. CAPACITOR LEAKAGE DOMINATES AT T CAPS ARE SPRAGUE 595D 
2.5 3.0
2.0 INPUT VOLTAGE (V)
MAX858/MAX859
vs. LOAD CURRENT
V
= 5V
OUT
1 100
LOAD CURRENT (mA)
MAX858/MAX859
MAXIMUM OUTPUT CURRENT
vs. INPUT VOLTAGE
= 3.3V
V
= 5.0V
OUT
2.0
1.5
2.5 3.0
INPUT VOLTAGE (V)
= +85°C.
A
3.5
3.5
MAX856-09
4.0
MAX856-07
MAX856-12
4.0
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