EVALUATION KIT AVAILABLE
MAX1674/MAX1675/MAX1676
High-Efficiency, Low-Supply-Current,
Compact, Step-Up DC-DC Converters
LE
AVAILAB
General Description
The MAX1674/MAX1675/MAX1676 compact, high-efficiency, step-up DC-DC converters fit in small µMAX
packages. They feature a built-in synchronous rectifier,
which improves efficiency and reduces size and cost
by eliminating the need for an external Schottky diode.
Quiescent supply current is only 16µA.
The input voltage ranges from 0.7V to VOUT, where
VOUT can be set from 2V to 5.5V. Start-up is guaranteed from 1.1V inputs. The MAX1674/MAX1675/
MAX1676 have a preset, pin-selectable output for 5V or
3.3V. The outputs can also be adjusted to other voltages using two external resistors.
All three devices have a 0.3Ω N-channel MOSFET
power switch. The MAX1674 has a 1A current limit. The
MAX1675 has a 0.5A current limit, which permits the
use of a smaller inductor. The MAX1676 comes in a
10-pin µMAX package and features an adjustable current limit and circuitry to reduce inductor ringing.
________________________Applications
Pagers
Wireless Phones
Medical Devices
Hand-Held Computers
____________________________Features
♦ 94% Efficient at 200mA Output Current
♦ 16µA Quiescent Supply Current
♦ Internal Synchronous Rectifier (no external diode)
♦ 0.1µA Logic-Controlled Shutdown
♦ LBI/LBO Low-Battery Detector
♦ Selectable Current Limit for Reduced Ripple
♦ Low-Noise, Anti-Ringing Feature (MAX1676)
♦ 8-Pin and 10-Pin µMAX Packages
♦ Preassembled Evaluation Kit (MAX1676EVKIT)
_______________Ordering Information
PART
TEMP. RANGE
PIN-PACKAGE
MAX1674EUA
MAX1675EUA
MAX1676EUB
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
8 µMAX
8 µMAX
10 µMAX
PDAs
RF Tags
Pin Configurations
1 to 3-Cell Hand-Held Devices
Functional Diagrams
Typical Operating Circuit
TOP VIEW
FB 1
INPUT
0.7V TO VOUT
LBI
2
LBO
3
MAX1674
MAX1675
REF 4
ON
SHDN
OFF
LX
MAX1674 OUT
MAX1675
OUTPUT
3.3V, 5V, OR
ADJ (2V TO 5.5V)
UP TO 300mA
FB 1
LBI
REF
0.1µF
LBO
FB
LOW-BATTERY
DETECT OUT
GND
Pin Configurations appear at end of data sheet.
Functional Diagrams continued at end of data sheet.
UCSP is a trademark of Maxim Integrated Products, Inc.
OUT
7
LX
6
GND
5
SHDN
µMAX
10 OUT
LBI 2
LOW-BATTERY
DETECT IN
8
LBO 3
MAX1676
9
LX
8
GND
CLSEL 4
7
BATT
REF 5
6
SHDN
µMAX
For pricing, delivery, and ordering information, please contact Maxim Direct
at 1-888-629-4642, or visit Maxim’s website at www.maximintegrated.com.
19-1360; Rev 3; 3/00
MAX1674/MAX1675/MAX1676
High-Efficiency, Low-Supply-Current,
Compact, Step-Up DC-DC Converters
ABSOLUTE MAXIMUM RATINGS
Supply Voltage (OUT to GND) ..............................-0.3V to +6.0V
Switch Voltage (LX to GND) .....................-0.3V to (VOUT + 0.3V)
Battery Voltage (BATT to GND).............................-0.3V to +6.0V
SHDN, LBO to GND ..............................................-0.3V to +6.0V
LBI, REF, FB, CLSEL to GND ...................-0.3V to (VOUT + 0.3V)
Switch Current (LX) ...............................................-1.5A to +1.5A
Output Current (OUT) ...........................................-1.5A to +1.5A
Continuous Power Dissipation (TA = +70°C)
8-Pin µMAX (derate 4.1mW/°C above +70°C) .............330mW
10-Pin µMAX (derate 5.6mW/°C above +70°C) ...........444mW
Operating Temperature Range ...........................-40°C to +85°C
Junction Temperature ......................................................+150°C
Storage Temperature Range .............................-65°C to +165°C
Lead Temperature (soldering, 10s) .................................+300°C
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.
ELECTRICAL CHARACTERISTICS
(VBATT = 2V, FB = OUT (VOUT = 3.3V), RL = ˙∞, TA = 0°C to +85°C, unless otherwise noted. Typical values are at TA = +25°C.)
PARAMETER
SYMBOL
CONDITIONS
MIN
Operating Voltage
VIN
Start-Up Voltage
1.1
TA = +25°C
VOUT
3.17
3.30
3.43
4.80
5
5.20
IOUT
VREF
300
420
MAX1675,
MAX1676 (CLSEL = GND)
150
220
MAX1674,
MAX1676 (CLSEL = OUT)
180
285
MAX1675,
MAX1676 (CLSEL = GND)
90
130
IREF = 0
1.274
1.30
1.326
0.024
TEMPCO
V
V
V
mV/°C
Reference Voltage Load
Regulation
VREF_LOAD
IREF = 0 to 100µA
3
15
mV
Reference Voltage Line
Regulation
VREF_LINE
VOUT = 2V to 5.5V
0.08
2.5
mV/V
1.30
1.326
V
0.3
0.6
Ω
1.274
FB, LBI Input Threshold
Internal NFET, PFET
On-Resistance
LX Switch Current
Limit (NFET)
LX Leakage Current
2
V
mA
FB = GND
(VOUT = 5V)
Reference Voltage Tempco
5.5
MAX1674,
MAX1676 (CLSEL = OUT)
V
mV/°C
FB = GND
FB = OUT
(VOUT = 3.3V)
Reference Voltage
1.1
FB = OUT
2
UNITS
V
-2
Output Voltage Range
Steady-State Output Current
(Note 2)
MAX
5.5
0.9
TA = +25°C, RL = 3kΩ (Note 1)
Start-Up Voltage Tempco
Output Voltage
TYP
0.7
Minimum Input Voltage
RDS(ON)
ILIM
ILEAK
ILX = 100mA
MAX1674, MAX1676 (CLSEL = OUT)
0.80
1
1.20
MAX1675, MAX1676 (CLSEL = GND)
0.4
0.5
0.65
0.05
1
VLX = 0, 5.5V; VOUT = 5.5V
A
µA
Maxim Integrated
MAX1674/MAX1675/MAX1676
High-Efficiency, Low-Supply-Current,
Compact, Step-Up DC-DC Converters
ELECTRICAL CHARACTERISTICS (continued)
(VBATT = 2V, FB = OUT (VOUT = 3.3V), RL = ˙∞, TA = 0°C to +85°C, unless otherwise noted. Typical values are at TA = +25°C.)
PARAMETER
Operating Current into OUT
(Note 3)
Shutdown Current into OUT
SYMBOL
Efficiency
CONDITIONS
MIN
TYP
MAX
UNITS
VFB = 1.4V, VOUT = 3.3V
16
35
µA
SHDN = GND
0.1
1
µA
VOUT = 3.3V, ILOAD = 200mA
90
VOUT = 2V, ILOAD = 1mA
85
LX Switch On-Time
tON
VFB = 1V, VOUT = 3.3V
3
LX Switch Off-Time
tOFF
VFB = 1V, VOUT = 3.3V
0.8
FB Input Current
IFB
VFB = 1.4V
ILBI
VLBI = 1.4V
%
4
7
µs
1
1.2
µs
0.03
50
nA
1
50
nA
CLSEL Input Current
ICLSEL
MAX1676, CLSEL = OUT
1.4
3
µA
SHDN Input Current
I SHDN
V SHDN = 0 or VOUT
0.07
50
nA
VLBI = 0, ISINK = 1mA
0.2
0.4
V
V LBO = 5.5V, VLBI = 5.5V
0.07
1
µA
150
Ω
LBI Input Current
LBO Low Output Voltage
LBO Off Leakage Current
I LBO
Damping Switch Resistance
SHDN Input Voltage
CLSEL Input Voltage
MAX1676, VBATT = 2V
88
VIL
0.2VOUT
VIH
0.8VOUT
VIL
0.2VOUT
VIH
0.8VOUT
V
V
ELECTRICAL CHARACTERISTICS
(VBATT = 2V, FB = OUT, RL = ∞, TA = -40°C to +85°C, unless otherwise noted.) (Note 4)
PARAMETER
Output Voltage
SYMBOL
VOUT
MIN
MAX
FB = OUT
CONDITIONS
3.13
3.47
FB = GND
4.75
5.25
Output Voltage Range
Reference Voltage
VREF
IREF = 0
FB, LBI Thresholds
Internal NFET, PFET
On-Resistance
2.20
5.5
V
1.3325
V
1.2675
1.3325
V
0.6
Ω
40
µA
VFB = 1.4V, VOUT = 3.3V
SHDN = GND
Shutdown Current into OUT
V
1.2675
RDS(ON)
Operating Current into OUT
(Note 3)
UNITS
1
µA
LX Switch On-Time
tON
VFB = 1V, VOUT = 3.3V
2.7
7.0
µs
LX Switch Off-Time
tOFF
VFB = 1V, VOUT = 3.3V
0.75
1.25
µs
MAX1674, MAX1676 (CLSEL = OUT)
0.75
1.25
MAX1675, MAX1676 (CLSEL = GND)
0.36
0.69
LX Switch Current
Limit (NFET)
Maxim Integrated
ILIM
A
3
MAX1674/MAX1675/MAX1676
High-Efficiency, Low-Supply-Current,
Compact, Step-Up DC-DC Converters
ELECTRICAL CHARACTERISTICS (continued)
(VBATT = 2V, FB = OUT, RL = ∞, TA = -40°C to +85°C, unless otherwise noted.) (Note 4)
MAX
UNITS
CLSEL Input Current
PARAMETER
SYMBOL
ICLSEL
MAX1676, CLSEL = OUT
3
µA
SHDN Input Current
I SHDN
VSHDN = 0 or VOUT
75
nA
V LBO = 5.5V, VLBI = 5.5V
1
µA
LBO Off Leakage Current
I LBO
CONDITIONS
MIN
Note 1: Start-up voltage operation is guaranteed with the addition of a Schottky MBR0520 external diode between the input and
output.
Note 2: Steady-state output current indicates that the device maintains output voltage regulation under load. See Figures 5 and 6.
Note 3: Device is bootstrapped (power to the IC comes from OUT). This correlates directly with the actual battery supply.
Note 4: Specifications to -40°C are guaranteed by design, not production tested.
Typical Operating Characteristics
(L = 22µH, CIN = 47µF, COUT = 47µF 0.1µF, CREF = 0.1µF, TA = +25°C, unless otherwise noted.)
EFFICIENCY vs. LOAD CURRENT
80
VIN = 2.4V
70
EFFICIENCY (%)
EFFICIENCY (%)
90
VIN = 1.2V
60
50
40
50
40
20
20
VOUT = 5V
ILIMIT = 500mA
10
0
0.01
0.1
1
10
100
VIN = 3.6V
VIN = 1.2V
60
30
0
0.01
0.1
1
10
100
VOUT = 3.3V
ILIMIT = 500mA
0
1000
0.01
0.1
VIN = 2.4V
VIN = 1.2V
60
50
40
30
20
VOUT = 3.3V
ILIMIT = 1A
10
0
1
10
LOAD CURRENT (mA)
100
1
10
100
1000
LOAD CURRENT (mA)
1000
MAX1674 toc05
1.300
REFERENCE OUTPUT VOLTAGE (V)
MAX1674 toc04
80
EFFICIENCY (%)
40
REFERENCE OUTPUT VOLTAGE
vs. TEMPERATURE
90
4
50
LOAD CURRENT (mA)
100
0.1
60
10
EFFICIENCY vs. LOAD CURRENT
0.01
VIN = 1.2V
20
VOUT = 5V
ILIMIT = 1A
LOAD CURRENT (mA)
70
VIN = 2.4V
70
30
10
1000
80
VIN = 2.4V
70
30
90
EFFICIENCY (%)
VIN = 3.6V
80
100
MAX1674 toc02
MAX1674 toc01
90
EFFICIENCY vs. LOAD CURRENT
100
MAX1674 toc03
EFFICIENCY vs. LOAD CURRENT
100
1.298
IREF = 0
1.296
1.294
IREF = 100µA
1.292
1.290
-40
-20
0
20
40
60
80
100
TEMPERATURE (°C)
Maxim Integrated
MAX1674/MAX1675/MAX1676
High-Efficiency, Low-Supply-Current,
Compact, Step-Up DC-DC Converters
Typical Operating Characteristics (continued)
(L = 22µH, CIN = 47µF, COUT = 47µF 0.1µF, CREF = 0.1µF, TA = +25°C, unless otherwise noted.)
NO-LOAD BATTERY CURRENT
vs. INPUT BATTERY VOLTAGE
100
80
ILIMIT = 0.5A, 5.0V
60
ILIMIT = 0.5A, 3.3V
20
ILIMIT = 1A, 3.3V
0
1.0
0.8
0.6
WITH 1N5817
-1.0
0.01
0.1
1
100
MAXIMUM OUTPUT CURRENT
vs. INPUT VOLTAGE (VOUT = 3.3V)
0.6
0.4
0.2
MAX1674toc11
1A CURRENT LIMIT
600
500
400
300
200
0.5A CURRENT LIMIT
800
MAXIMUM OUTPUT CURRENT (mA)
0.8
800
700
100
0
1.0
1.5
2.0
MAX1674 TOC13
2.5
3.0
3.5
4.0
0.5A CURRENT LIMIT
100
1.0 1.2 1.4 1.6 1.8 2.0 2.2 2.4 2.6 2.8 3.0
1.2
MAX1674toc13.5
P-CHANNEL
0.35
MAX1674, MAX1676 (CLSEL = OUT)
1.0
0.8
0.30
ILIM (A)
RESISTANCE (Ω)
200
LX CURRENT LIMIT
vs. OUTPUT VOLTAGE
N-CHANNEL
0.25
0.20
0.6
0.4
0.15
MAX1675, MAX1676 (CLSEL = GND)
0.10
0.2
0.05
0
-60 -40
-20
0
20
40
TEMPERATURE (°C)
Maxim Integrated
300
4.5
0
1µs/div
400
SWITCH RESISTANCE vs. TEMPERATURE
0.40
VOUT
AC COUPLED
100mV/div
1A CURRENT LIMIT
500
INPUT VOLTAGE (V)
0.45
VLX
5V/div
ILX
0.5A/div
600
INPUT VOLTAGE (V)
SUPPLY VOLTAGE (V)
HEAVY-LOAD SWITCHING WAVEFORMS
700
0
0
0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0
1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5
SUPPLY VOLTAGE (V)
900
MAXIMUM OUTPUT CURRENT (mA)
MAX1674TOC10
SHUTDOWN THRESHOLD (V)
1
10
LOAD CURRENT (mA)
MAXIMUM OUTPUT CURRENT
vs. INPUT VOLTAGE (VOUT = 5V)
1.0
VIN = 2.4V
VOUT = 5.0V
-0.4
-0.8
SHUTDOWN THRESHOLD
vs. SUPPLY VOLTAGE
0
0
-0.2
-0.6
INPUT BATTERY VOLTAGE (V)
1.2
0.2
0.2
0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5
1.4
0.4
0.4
0
0
MAX167toc09
MAX1674toc08
WITHOUT DIODE
0.6
MAX1674toc12
40
1.4
1.2
0.8
MAX1674toc14
ILIMIT = 1A, 5.0V
1.0
SHUTDOWN CURRENT (µA)
120
1.6
START-UP VOLTAGE (V)
140
INPUT BATTERY CURRENT (µA)
1.8
MAX1674toc07
160
SHUTDOWN CURRENT
vs. SUPPLY VOLTAGE
START-UP VOLTAGE
vs. LOAD CURRENT
60
80
100
2.0
2.5
3.0
3.5
4.0
4.5
5.0
OUTPUT VOLTAGE (V)
5
MAX1674/MAX1675/MAX1676
High-Efficiency, Low-Supply-Current,
Compact, Step-Up DC-DC Converters
Typical Operating Characteristics (continued)
(L = 22µH, CIN = 47µF, COUT = 47µF 0.1µF, CREF = 0.1µF, TA = +25°C, unless otherwise noted.)
LOAD-TRANSIENT RESPONSE
LINE-TRANSIENT RESPONSE
MAX1674 TOC17
VIN = 2.4V
VOUT = 3.3V
VIN
2V TO 3V
1V/div
VOUT
2V/div
IOUT
200mA/div
VSHDN
2V/div
VOUT
50mV/div
AC
COUPLED
VOUT
AC COUPLED
100mV/div
ILOAD
100mA
EXITING SHUTDOWN
MAX1674 TOC16
MAX1674 TOC15
5µs/div
10µs/div
500µs/div
Pin Description
PIN
NAME
FUNCTION
MAX1674
MAX1675
MAX1676
1
1
FB
Dual-Mode™ Feedback Input. Connect to GND for +5.0V output.
Connect to OUT for +3.3V output. Use a resistor network to set the
output voltage from +2.0V to +5.5V.
2
2
LBI
Low-Battery Comparator Input. Internally set to trip at +1.30V.
3
3
LBO
Open-Drain Low-Battery Comparator Output. Connect LBO to OUT
through a 100kΩ resistor. Output is low when VLBI is 80% of VOUT) for operating mode.
Drive low (