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19-3671; Rev 0; 5/05
KIT ATION EVALU E AILABL AV
200mA Step-Up Converters in 6-Pin SOT23 and TDFN
Features
o Over 200mA Available Output Current o 1.5V to 5.5V Input Voltage Range o BATT Connected to OUT in Shutdown for Backup Power o Up to 95% Efficiency o 7A Typical Quiescent Current o <1A Shutdown Supply Current o Internal Synchronous Rectifier o 750mA Switch Current Limit o RST Output (MAX8569B) o Adjustable Output Voltage (MAX8569A) o Fixed 3.0V or 3.3V Output Voltage (MAX8569B)
General Description
The MAX8569A/MAX8569B low-quiescent-current boost regulators provide up to 200mA at output voltages up to 5.5V from a 1.5V to 5.5V input source. The built-in synchronous rectifier allows for over 90% efficiency while achieving small size and low cost by eliminating the need for an external Schottky diode. The MAX8569A provides an adjustable output while the MAX8569B is fixed at 3.0V or 3.3V. The MAX8569B features a power-on reset output (RST) to signal that the output has reached regulation. All devices connect the battery input to the output during shutdown, allowing the input battery to be used as a backup or real-time clock supply when the converter is off.
MAX8569A/MAX8569B
Applications
Medical Diagnostic Equipment Digital Cameras PDAs and Smartphones Cordless Phones Battery Backup PC Cards Local 3.3V or 5V Supply
Ordering Information
PART MAX8569AEUT-T* MAX8569AETT+ MAX8569BEUT-T* MAX8569BETT+ MAX8569BETT30+ TEMP RANGE -40C to +85C -40C to +85C -40C to +85C -40C to +85C -40C to +85C PIN-PACKAGE 6 SOT23-6 (U6FH-6) 6 TDFN 3mm x 3mm (T633-1) 6 SOT23-6 (U6FH-6) 6 TDFN 3mm x 3mm (T633-1) 6 TDFN 3mm x 3mm (T633-1)
Typical Operating Circuit
BATT 2V INPUT ON OFF SHDN GND MAX8569B RST POWER-ON RESET OUT 3.3V, 200mA OUTPUT
LX
*Future product--contact factory for availability. Selector Guide appears at end of data sheet. +Denotes lead-free packaging.
Pin Configurations
OUT LX
TOP VIEW
FB (RST)
TOP VIEW
SHDN 1 MAX8569A (MAX8569B) 6 FB (RST)
6
5
4
BATT 2
5 OUT
MAX8569A (MAX8569B)
GND 3
4 LX
+
1 SHDN
2 BATT
3 GND
SOT23
( ) ARE FOR THE MAX8569B + DENOTES LEAD-FREE PACKAGING
TDFN
________________________________________________________________ Maxim Integrated Products
1
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at 1-888-629-4642, or visit Maxim's website at www.maxim-ic.com.
200mA Step-Up Converters in 6-Pin SOT23 and TDFN MAX8569A/MAX8569B
ABSOLUTE MAXIMUM RATINGS
BATT, LX, OUT, FB, RST to GND .............................-0.3V to +6V SHDN to GND...........................................-0.3V to (VOUT + 0.3V) LX Current ....................................................................1.5A Peak Continuous Power Dissipation (TA = +70C) 6-Pin SOT23 (derate 9.1mW/C above +70C)............727mW 6-Pin TDFN 3mm x 3mm (derate 18.2mW/C above +70C) .............................1454mW Operating Temperature Range ...........................-40C to +85C Junction Temperature ......................................................+150C Storage Temperature Range .............................-65C to +150C Lead Temperature (soldering, 10s) .................................+300C
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
(VSHDN = VOUT = 3.3V, VBATT = 2.0V, TA = -40C to +85C. Typical values are at TA = +25C, unless otherwise noted.) (Note 1)
PARAMETER Battery Input Range Startup Voltage RLOAD = 2.6k MAX8569A Output Voltage MAX8569BETT30 MAX8569B Feedback Threshold Feedback Bias Current n-Channel On-Resistance p-Channel On-Resistance n-Channel Switch Current Limit Switch Maximum On-Time Synchronous Rectifier ZeroCrossing Current OUT Quiescent Current OUT Shutdown Current BATT Quiescent Current BATT Shutdown Current SHDN Logic-Low MAX8569A MAX8569A, VFB = 1.27V ILX = 100mA ILX = 100mA TA = +25C TA = -40C to +85C VOUT = 2.8V TA = +25C TA = -40C to +85C VOUT = 3.5V, VFB = 1.3V (Note 2) VOUT = 3.5V, VSHDN = VFB = 0V VOUT = 3.5V, VFB = 1.3V (Note 3) VOUT = 3.5V, VSHDN = 0V 650 600 3.5 3 0 4 0.05 3 0.01 5 25 TA = +25C TA = -40C to +85C TA = +25C TA = -40C to +85C TA = +25C TA = -40C to +85C TA = +25C TA = -40C to +85C TA = +25C TA = -40C to +85C 2.0 2.94 2.925 3.233 3.217 1.208 1.203 3.5 4 0.3 0.3 750 0.7 0.9 920 975 6.5 50 60 10 1 10 1 0.3 1.228 3.300 3.0 CONDITIONS MIN 1.5 1.22 1.24 5.5 3.06 3.075 3.366 3.373 1.248 1.253 20 V nA mA s mA A A A A V V TYP MAX 5.5 1.5 UNITS V V
2
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200mA Step-Up Converters in 6-Pin SOT23 and TDFN
ELECTRICAL CHARACTERISTICS (continued)
(VSHDN = VOUT = 3.3V, VBATT = 2.0V, TA = -40C to +85C. Typical values are at TA = +25C, unless otherwise noted.) (Note 1)
PARAMETER SHDN Threshold CONDITIONS Rising edge, 100mV hysteresis (typ), VOUT = 2.8V VOUT = 5.5V IRST = 1mA, VOUT = 2.5V VRST = 5.5V Relative to OUT, 3.3V for MAX8569B, 3.0V for MAX8569BETT30 VOUT = 5.5V VBATT = 2V, VOUT = 3.3V VBATT = 2V, VOUT = 3.3V, Figures 1 or 2, ILOAD = 40mA TA = +25C TA = -40C to +85C TA = +25C TA = -40C to +85C TA = +25C TA = -40C to +85C 85 85 0.1 1 90 90 1 150 200 88 95 % 97 150 nA mA % TA = +25C TA = -40C to +85C TA = +25C TA = -40C to +85C MIN 1.185 1.170 13 13 0.2 100 TYP 1.228 MAX 1.271 V 1.286 100 nA V nA UNITS
MAX8569A/MAX8569B
SHDN Input Bias Current RST Low Voltage RST Leakage Current
RST Threshold
LX Leakage Current Maximum Load Current Efficiency
Note 1: Specifications to -40C are guaranteed by design and not production tested. Note 2: Supply current into OUT. This current is drawn from the source battery, but is reduced in value according to the step-up ratio and efficiency. Note 3: Does not include switching losses and output quiescent current. See the Input Current and Output Voltage vs. Input Voltage (On, 330) graph in the Typical Operating Characteristics for operating quiescent current.
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3
200mA Step-Up Converters in 6-Pin SOT23 and TDFN MAX8569A/MAX8569B
Typical Operating Characteristics
(Circuit of Figure 2, VOUT = 3.3V, VBATT = +2V, TA = +25C, circuit of Figure 1, TA = +25C, unless otherwise noted.)
EFFICIENCY vs. LOAD CURRENT VOUT = 5V
MAX8569 toc01
EFFICIENCY vs. LOAD CURRENT VOUT = 3.3V
VIN = 2.5V 90 VIN = 2V EFFICIENCY (%) 85 VIN = 1.5V 80 75 70 65
MAX8569 toc02
100 95 90 EFFICIENCY (%) 85 80 75 70 65 1 10 100 VIN = 4.2V VIN = 3.3V VIN = 2.5V
95
1000
1
10
100
1000
LOAD CURRENT (mA)
LOAD CURRENT (mA)
EFFICIENCY vs. LOAD CURRENT VOUT = 2.5V
95 90 EFFICIENCY (%) 85 80 75 70 65 60 1 10 100 1000 LOAD CURRENT (mA) VIN = 1.5V VIN = 2V
MAX8569 toc03
MAXIMUM OUTPUT CURRENT vs. BATTERY VOLTAGE
MAX8569 toc04
100
600 MAXIMUM OUTPUT CURRENT (mA) 500 400 300 VOUT = 5V 200 100 0 1.5 2.5 3.5 4.5 VOUT = 2.5V
VOUT = 3.3V
5.5
BATTERY VOLTAGE (V)
STARTUP VOLTAGE vs. LOAD RESISTANCE
1.32 STARTUP VOLTAGE (V) 1.30 1.28 1.26 1.24 1.22 1.20 10 100 RLOAD () 1k 10k
MAX8569 toc05
OUTPUT VOLTAGE AND INPUT CURRENT vs. INPUT VOLTAGE (SHUTDOWN, NO LOAD)
6 5 OUTPUT VOLTAGE (V) 4 3 2 1 0 0 1 2 3 4 5 6 BATTERY VOLTAGE (V) IBATT VOUT
MAX8569 toc06
1.34
6 5 4 3 2 1 0 BATTERY CURRENT (A)
4
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200mA Step-Up Converters in 6-Pin SOT23 and TDFN MAX8569A/MAX8569B
Typical Operating Characteristics (continued)
(Circuit of Figure 2, VOUT = 3.3V, VBATT = +2V, TA = +25C, circuit of Figure 1, TA = +25C, unless otherwise noted.)
OUTPUT VOLTAGE AND INPUT CURRENT vs. INPUT VOLTAGE (SHUTDOWN, 200mA LOAD)
6 5 OUTPUT VOLTAGE (V) 4 3 2 IBATT 1 0 0 1 2 3 4 5 6 BATTERY VOLTAGE (V) 1 0.5 0 0 0 1 2 3 4 5 6 BATTERY VOLTAGE (V) 0.5 0 VOUT
MAX8569 toc07
OUTPUT VOLTAGE AND INPUT CURRENT vs. INPUT VOLTAGE (ON, 330)
4.5 4.0 BATTERY CURRENT (A) OUTPUT VOLTAGE (V) 3.5 3.0 2.5 2.0 1.5 1.0 IBATT VOUT
MAX8569 toc08
6 5 4 3 2
4.5 4.0 BATTERY CURRENT (A) 3.5 3.0 2.5 2.0 1.5 1.0
OUTPUT VOLTAGE AND INPUT CURRENT vs. INPUT VOLTAGE (ON, 16 LOAD)
4.5 4.0 OUTPUT VOLTAGE (V) 3.5 3.0 2.5 2.0 1.5 1.0 0.5 0 0 1 2 3 4 5 6 BATTERY VOLTAGE (V) IBATT VOUT
MAX8569 toc09
ON/OFF RESPONSE (RLOAD = 33)
4.5 4.0 BATTERY CURRENT (A) 3.5 3.0 2.5 2.0 1.5 1.0 0.5 0 100s/div VOUT
MAX8569 toc10
1V/div
VIN 1V/div
LOAD TRANSIENT
MAX8569 toc11
LINE TRANSIENT
MAX8569 toc12
100mV/div VOUT (AC-COUPLED)
VOUT (AC-COUPLED)
100mV/div
200mA IOUT 20mA VIN
2.5V 2V
100s/div
100ms/div
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5
200mA Step-Up Converters in 6-Pin SOT23 and TDFN MAX8569A/MAX8569B
Typical Operating Characteristics (continued)
(Circuit of Figure 2, VOUT = 3.3V, VBATT = +2V, TA = +25C, circuit of Figure 1, TA = +25C, unless otherwise noted.)
SHUTDOWN RESPONSE (RLOAD = 33) SWITCHING WAVEFORMS (RLOAD = 33)
MAX8569 toc13
MAX8569 toc14
VOUT (AC-COUPLED) 3.3V VOUT 2V VLX
100mV/div
2V/div
VSHDN
IL 2V/div
500mA/div
100s/div
10s/div
Pin Description
PIN MAX8569A 1 MAX8569B 1 NAME FUNCTION Shutdown Input. Drive SHDN low to place the MAX8569 in shutdown mode. SHDN can be used for a low-battery cutoff (1.228V threshold). See the Low-Battery Cutoff section for details. Drive SHDN high for normal operation. Battery Voltage Connection. Connect BATT to a 1.5V to 5.5V supply. Bypass BATT to GND with a 10F or larger ceramic capacitor. Ground Inductor Connection. Connect the switched side of the inductor to LX. During shutdown, LX is connected to OUT. Output Voltage. Bypass OUT to GND with a 10F or larger ceramic capacitor. During shutdown, OUT is connected to LX. OUT is also the bootstrapped supply input for the IC. Feedback Input. Connect FB to the center tap of an external resistor-divider from OUT to GND to set the output voltage. VFB regulates to 1.228V. Reset Output. RST is an open-drain output that goes high impedance when the output voltage rises above 90% of the nominal regulation voltage. RST pulls low when the output is below 90% of the nominal regulation voltage. RST is high impedance during shutdown. Exposed Paddle (TDFN Package Only). Connect to the PC board ground plane for increased thermal performance.
SHDN
2 3 4 5 6
2 3 4 5 --
BATT GND LX OUT FB
--
6
RST
--
--
EP
6
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200mA Step-Up Converters in 6-Pin SOT23 and TDFN
Detailed Description
The MAX8569A and MAX8569B compact high-efficiency step-up converters feature low-quiescent supply current to ensure the highest possible efficiency over a wide load range. With a minimum 1.5V input voltage, these devices are well suited for applications with two alkaline cells, two nickel-metal-hydride (NiMH) cells, or one lithium-ion (Li+) cell. When SHDN is low, the output is connected to the battery through the inductor and an internal p-channel MOSFET. This allows the input battery to be used as a backup or real-time clock supply when the converter is off by eliminating the voltage drop across the MOSFET body diode. These devices are ideal for low-power applications where a small footprint is critical. The internal synchronous rectifier improves efficiency significantly and reduces size and cost by eliminating the need for an external Schottky diode. Instead, switch on-time is terminated when the inductor current reaches the 780mA (typ) n-channel current limit, or when the 5s maximum n-channel switch on-time is reached. Following each on-cycle, the synchronous rectifier turns on, shunts the MOSFET body diode, and the inductor current ramps to zero before another cycle begins. The next cycle occurs when the error comparator senses that the output has fallen below the regulation threshold.
MAX8569A/MAX8569B
Applications Information
Shutdown
Drive SHDN low to shut down the MAX8569A/ MAX8569B and reduce the input current to less than 1A. During shutdown, the battery input is connected to the output through the inductor and the internal synchronous rectifier. This allows the input battery (rather than a separate backup battery) to provide backup power for devices such as an idled microcontroller, SRAM, or real-time clock, without the usual diode forward drop. Drive SHDN to VOUT (logic-high) to enable the IC for normal operation.
Control Scheme
The MAX8569A/MAX8569B feature a current-limited control scheme that provides ultra-low quiescent current and high efficiency over a wide output current range. The switching cycles are not controlled by an oscillator.
2 L1 10H C1 10F
BATT MAX8569A
OUT
5 R3 168k C3 22F
3.3V OUTPUT
1.5V TO 3V INPUT
4
LX
R1 220k 1 R2 1M C2 0.01F SHDN GND 3
FB
6 R4 100k
Figure 1. Typical Application Circuit for MAX8569A
2 L1 10H
BATT MAX8569B
OUT
5 C3 22F R1 100k
3.3V OUTPUT
1.5V TO 3V INPUT C1 10F
4
LX
RST ON OFF 1
6
RESET OUTPUT
SHDN GND 3
Figure 2. Typical Application Circuit for MAX8569B _______________________________________________________________________________________ 7
200mA Step-Up Converters in 6-Pin SOT23 and TDFN MAX8569A/MAX8569B
Low-Battery Cutoff
The SHDN trip threshold of the MAX8569A/MAX8569B can be used as an input voltage detector that disables the IC when the battery voltage falls to a set level. The SHDN trip threshold is 1.228V. Use a resistor-divider to set the battery-detection voltage (R1 and R2 in Figure 1). Select R2 between 100k and 1M to minimize battery drain. Calculate R1 as follows: R1 = R2 x ((VOFF / V SHDN) - 1) where VOFF is the battery voltage at which the part shuts down and V SHDN = 1.228V. Note that input ripple can sometimes cause false shutdowns. To minimize the effect of ripple, connect a low-value capacitor (C2) from SHDN to GND to filter out input noise. Select a C2 value so the R1, C2 time constant is above 2ms. where RL is the inductor series resistance and RNCH is the RDS(ON) of the internal n-channel MOSFET (0.3 typ).
Capacitor Selection
Choose an output capacitor to achieve the desired output ripple percentage. COUT > (0.5 x L x 0.780A2) / (r% x VOUT2) where L is the inductor value and r is the desired output ripple in %. A 22F ceramic capacitor is a good starting value. The input capacitor reduces the peak current drawn from the battery and can be the same value as the output capacitor. A larger input capacitor can be used to further reduce the input ripple and improve efficiency.
PC Board Layout and Grounding
Careful printed circuit layout is important for minimizing ground bounce and noise. Keep the IC's GND pin and the ground leads of the input- and output-filter capacitors less than 0.2in (5mm) apart. In addition, keep all connections to the FB and LX pins as short as possible. In particular, when using external feedback resistors, locate them as close to FB as possible. To maximize output power and efficiency and minimize output ripple voltage, use a ground plane and solder the IC's GND directly to the ground plane. A sample layout is available in the MAX8569A/MAX8569B evaluation kit to speed designs.
Power-On Reset (RST, MAX8569B)
The MAX8569B provides a power-on reset output (RST) that goes high impedance when the output reaches 90% of its regulation point. RST pulls low when the output is below 90% of the regulation point. Connect a 100k to 1M pullup resistor from RST to OUT to provide a logic control signal for a microprocessor. Connect RST to GND when the reset function is not used.
Setting the Output Voltage (MAX8569A)
The output of the MAX8569A is adjustable from 2V to 5.5V. Connect a resistor-divider from the output to ground with FB connected to the center tap to set the desired output voltage (R3 and R4, Figure 1). Select R4 between 100k and 1M. R3 is then calculated as follows: R3 = R4 x ((VOUT / VFB) - 1) where VOUT is the desired output voltage and VFB is 1.228V.
Chip Information
PROCESS: BiCMOS
Selector Guide
PART MAX8569AEUT MAX8569BEUT MAX8569AETT MAX8569BETT MAX8569BETT30 OUTPUT VOLTAGE Adjustable Fixed 3.3V Adjustable Fixed 3.3V Fixed 3.0V PINPACKAGE SOT23-6 SOT23-6 TDFN TDFN TDFN TOP MARK ABWK ABWL AJN AJO AJP
Inductor Selection
The control scheme of the MAX8569A/MAX8569B permits flexibility in choosing an inductor. A 10H inductor performs well for most applications, but values from 4.7H to 100H can be used as well. Small inductance values typically offer smaller physical size. Output power is reduced when the inductance is large enough to prevent the maximum current limit (780mA) from being reached before the maximum on-time (5s) expires. For maximum output current, choose L so that:
VBATT(MAX) x 1s 0.78A IOUT(MAX) =
0.78A 0.78A x VBATT(MIN) - x (RNCH + RL ) 2 2 VOUT
8
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200mA Step-Up Converters in 6-Pin SOT23 and TDFN
Package Information
(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information go to www.maxim-ic.com/packages.)
MAX8569A/MAX8569B
D2 D A2
N
PIN 1 ID
0.35x0.35 b
PIN 1 INDEX AREA
E DETAIL A
E2 e
[(N/2)-1] x e REF.
A1
k
C L
C L
A
L e e
L
PACKAGE OUTLINE, 6,8,10 & 14L, TDFN, EXPOSED PAD, 3x3x0.80 mm
-DRAWING NOT TO SCALE-
21-0137
G
1
2
_______________________________________________________________________________________
6, 8, &10L, DFN THIN.EPS
9
200mA Step-Up Converters in 6-Pin SOT23 and TDFN MAX8569A/MAX8569B
Package Information (continued)
(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information go to www.maxim-ic.com/packages.)
COMMON DIMENSIONS SYMBOL A D E A1 L k A2 MIN. 0.70 2.90 2.90 0.00 MAX. 0.80 3.10 3.10 0.05
0.20 0.40 0.25 MIN. 0.20 REF.
PACKAGE VARIATIONS PKG. CODE T633-1 T633-2 T833-1 T833-2 T833-3 T1033-1 T1433-1 T1433-2 N 6 6 8 8 8 10 14 14 D2 1.50-0.10 1.50-0.10 1.50-0.10 1.50-0.10 1.50-0.10 1.50-0.10 1.70-0.10 1.70-0.10 E2 2.30-0.10 2.30-0.10 2.30-0.10 2.30-0.10 2.30-0.10 2.30-0.10 2.30-0.10 2.30-0.10 e 0.95 BSC 0.95 BSC 0.65 BSC 0.65 BSC 0.65 BSC 0.50 BSC 0.40 BSC 0.40 BSC JEDEC SPEC MO229 / WEEA MO229 / WEEA MO229 / WEEC MO229 / WEEC MO229 / WEEC MO229 / WEED-3 ------b 0.40-0.05 0.40-0.05 0.30-0.05 0.30-0.05 0.30-0.05 0.25-0.05 0.20-0.05 0.20-0.05 [(N/2)-1] x e 1.90 REF 1.90 REF 1.95 REF 1.95 REF 1.95 REF 2.00 REF 2.40 REF 2.40 REF
DOWNBONDS ALLOWED
NO NO NO NO YES NO YES NO
PACKAGE OUTLINE, 6,8,10 & 14L, TDFN, EXPOSED PAD, 3x3x0.80 mm
-DRAWING NOT TO SCALE-
21-0137
G
2
2
10
______________________________________________________________________________________
200mA Step-Up Converters in 6-Pin SOT23 and TDFN
Package Information (continued)
(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information go to www.maxim-ic.com/packages.)
6LSOT.EPS
MAX8569A/MAX8569B
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 ____________________ 11 (c) 2005 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products, Inc.

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