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19-0211; Rev 4; 5/96
NUAL KIT MA ATION HEET EVALU DATA S WS FOLLO
3.3V/5V or Adjustable-Output, Step-Up DC-DC Converters
____________________________Features
o o o o o o o o o o 0.8V to 6.0V Input Supply Voltage 0.8V Typ Start-Up Supply Voltage 85% Efficiency at 100mA 25A Quiescent Current 1A Shutdown Mode 125mA and 500mA Switch-Current Limits Permit Use of Low-Cost Inductors Up to 500kHz Switching Frequency 1.5% Reference Tolerance Over Temperature Low-Battery Detector (LBI/LBO) 8-Pin SO and MAX Packages
_______________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 VOUT 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 25A (1A 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.
MAX856-MAX859
______________Ordering Information
PART MAX856CSA MAX856CUA MAX856C/D MAX856ESA MAX856MJA MAX857CSA MAX857CUA MAX857C/D MAX857ESA MAX857MJA TEMP. RANGE 0C to +70C 0C to +70C 0C to +70C -40C to +85C -55C to +125C 0C to +70C 0C to +70C 0C to +70C -40C to +85C -55C to +125C PIN-PACKAGE 8 SO 8 MAX Dice* 8 SO 8 CERDIP 8 SO 8 MAX Dice* 8 SO 8 CERDIP
________________________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
INPUT 0.8V TO VOUT
Ordering Information continued at end of data sheet. * Dice are tested at TA = +25C only. Contact factory for availability.
__________________Pin Configuration
TOP VIEW
47H OUTPUT 5V AT 100mA OR 3.3V AT 125mA 68F
SHDN 3/5 1 2 8 7 LX GND OUT LBI
ON/OFF
SHDN
LX 1N5817
REF 3 LBO 4
MAX856 MAX858
6 5
MAX856
3V/5V SELECT LOW-BATTERY DETECTOR INPUT 3/5 LBI REF LBO LOW-BATTERY DETECTOR OUTPUT OUT
SHDN FB 1 2
SO/MAX
8 7
LX GND OUT LBI
GND
REF 3 LBO 4
MAX857 MAX859
6 5
SO/MAX ________________________________________________________________ Maxim Integrated Products 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 MAX856-MAX859
ABSOLUTE MAXIMUM RATINGS
Supply Voltage (OUT to GND) ...................................-0.3V, +7V Switch Voltage (LX to GND) .......................................-0.3V, +7V ---- --- SHDN , LBO to GND ....................................................-0.3V, +7V - - LBI, REF, 3/ 5, FB to GND .........................-0.3V, (VOUT + 0.3V) Reference Current (IREF) ..................................................2.5mA Continuous Power Dissipation (TA = +70C) SO (derate 5.88mW/C above +70C) .........................471mW MAX (derate 4.1mW/C above +70C) ......................330mW CERDIP (derate 8.00mW/C above +70C) .................640mW Reverse Battery Current (TA +45C, Note 1) .................750mA Operating Temperature Ranges MAX85_C_ _ ......................................................0C to +70C MAX85_E_ _ ....................................................-40C to +85C MAX85_MJA .................................................-55C to +125C Junction Temperature .....................................................+150C Storage Temperature Range ............................-65C to +160C Lead Temperature (soldering, 10sec) ............................+300C
Note 1: Reverse battery current is measured from the Typical Operating Circuit's battery input terminal to GND when the battery is 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.
ELECTRICAL CHARACTERISTICS
(Circuits of Figure 2, VIN = 2.5V, ILOAD = 0mA, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25C.) PARAMETER CONDITIONS - - MAX856, 3/ 5 = 0V, 0mA ILOAD 100mA - - MAX856, 3/ 5 = 3V, 0mA ILOAD 150mA 2V VIN 3V MAX857, VOUT = 5V, 0mA ILOAD 100mA - - MAX858, 3/ 5 = 0V, 0mA ILOAD 25mA - - MAX858, 3/ 5 = 3V, 0mA ILOAD 35mA MAX859, VOUT = 5V, 0mA ILOAD 25mA Minimum Start-Up Supply Voltage Minimum Operating Voltage Quiescent Supply Current in 3.3V Mode (Note 2) No Load Battery Current Shutdown Quiescent Current (Note 2) Peak Inductor Current Limit Reference Voltage - - ILOAD = 0mA, 3/ 5 = 3V, LBI = 1.5V, VOUT = 3.47V, (FB = 1.5V, MAX857/MAX859 only) Output set for 3.3V, measured at VIN in Figure 2, R3 omitted. ---- --- - - SHDN = 0V, 3/ 5 = 3V, LBI = 1.5V, VOUT = 3.47V, (FB = 1.5V, MAX857/MAX859 only) MAX856/MAX857 MAX858/MAX859 1.23 MAX85_C MAX85_E/M 1 500 125 1.25 0.8 1.22 1.25 25 ISINK = 2mA LBO = 5V 0.4 1 1.27 2.0 1.28 ILOAD = 0mA MIN 4.80 3.17 4.80 4.80 3.17 4.80 TYP 5.0 3.3 5.0 5.0 3.3 5.0 0.8 0.8 25 60 MAX UNITS 5.20 3.43 5.20 5.20 3.43 5.20 1.8 V V A V
Output Voltage
60 1 5
A
A
mA V % V mV V A
No REF load - - Reference-Voltage Regulation 3/ 5 = 3V, -20A REF load 250A, CREF = 0.22F LBI Input Threshold LBI Input Hysteresis LBO Output Voltage Low LBO Output Leakage Current With falling edge
2
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3.3V/5V or Adjustable-Output, Step-Up DC-DC Converters
ELECTRICAL CHARACTERISTICS (continued)
(Circuits of Figure 2, VIN = 2.5V, ILOAD = 0mA, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25C.) --- - - ---- - SHDN , 3/ 5 Input Voltage Low ---- --- - - SHDN , 3/ 5 Input Voltage High ---- --- - - SHDN , 3/ 5, FB, LBI Input Current FB Voltage Output Voltage Range 0.4 1.6 --- - ---- - - LBI = 1.5V, FB = 1.5V, SHDN = 0V or 3V, 3/ 5 = 0V or 3V MAX857/MAX859 MAX857/MAX859, ILOAD = 0mA (Note 3) 1.22 2.7 1.25 100 1.28 6.0 V V nA V V
MAX856-MAX859
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. VOUT = 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.
__________________________________________Typical Operating Characteristics
(Circuits of Figure 2, TA = +25C, unless otherwise noted.)
MAX858/MAX859 EFFICIENCY vs. OUTPUT CURRENT VOUT = 3.3V
MAX856-01
MAX858/MAX859 EFFICIENCY vs. OUTPUT CURRENT VOUT = 5V
90 80 VIN = 3.3V
MAX856-02
100 90 80 EFFICIENCY (%) VIN = 2.0V VIN = 1.5V VIN = 2.5V
100
EFFICIENCY (%)
70 60 50 40 30 20 10 0 0.001 0.01
70 60 50 40 30 20 10 0 VIN = 1.5V VIN = 2.5V
1 0.1 100 10 LOAD CURRENT (mA)
1000
0.001
0.01
1 0.1 100 10 LOAD CURRENT (mA)
1000
MAX856/MAX857 EFFICIENCY vs. OUTPUT CURRENT VOUT = 5V
90 80 EFFICIENCY (%) VIN = 2.0V EFFICIENCY (%) 70 60 50 40 30 20 10 0 0.001 0.01 100 1 0.1 10 LOAD CURRENT (mA) 1000 VIN = 1.5V VIN = 3.3V
MAX856-03
MAX856/MAX857 EFFICIENCY vs. OUTPUT CURRENT VOUT = 3.3V
90 80 70 60 50 40 30 20 10 0 0.001 0.01 100 1 0.1 10 LOAD CURRENT (mA) 1000 VIN = 1.5V VIN = 2.0V VIN = 2.5V
MAX856-04
100
100
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3
3.3V/5V or Adjustable-Output, Step-Up DC-DC Converters MAX856-MAX859
_____________________________Typical Operating Characteristics (continued)
(Circuits of Figure 2, TA = +25C, unless otherwise noted.)
MAX856/MAX857 NO LOAD BATTERY CURRENT vs. INPUT VOLTAGE
MAX856-08 MAX856-05
REFERENCE VOLTAGE vs. CURRENT
10 9 VREF LOAD REGULATION (mV) 8 7 6 5 4 3 2 1 0 0 100 200 50 150 REFERENCE LOAD CURRENT (A) 250 400 350 QUIESCENT CURRENT (A) 300 250 200 150 100 50 0 1.5
MAX858/MAX859 NO LOAD BATTERY CURRENT vs. INPUT VOLTAGE
1.4 QUIESCENT CURRENT (mA) 1.2 1.0 0.8 0.6 0.4 0.2 0 TA = -40C 1.5 2.0 2.5 3.0 3.5 4.0 TA = +25C TA = +85C INCLUDES ALL EXTERNAL COMPONENT LEAKAGES. CAPACITOR LEAKAGE DOMINATES AT TA = +85C. CAPS ARE SPRAGUE 595D
MAX856-09
1.6
TA = +85C INCLUDES ALL EXTERNAL COMPONENT LEAKAGES. CAPACITOR LEAKAGE DOMINATES AT TA = +85C. CAPS ARE SPRAGUE 595 D TA = +25C
TA = -40C
2.0
2.5
3.0
3.5
4.0
INPUT VOLTAGE (V)
INPUT VOLTAGE (V)
QUIESCENT CURRENT vs. INPUT VOLTAGE
MAX856-10
MAX856/MAX857 MINIMUM START-UP INPUT VOLTAGE vs. LOAD CURRENT
MAX856-06
START-UP INPUT VOLTAGE (V)
START-UP INPUT VOLTAGE (V)
1.4 QUIESCENT CURRENT (mA) 1.2 1.0 0.8 0.6 0.4 0.2 0 TA = -40C 1.5 2.0 2.5
SEE NOTE 2 IN THE ELECTRICAL CHARACTERISTICS
VOUT = 5V 1.10 1.05 1.00 0.95 0.90 0.85 0.80 0.75 VOUT = 3.3V
1.3 1.2 VOUT = 5V 1.1 1.0 0.9 0.8
TA = +85C 3.0 3.5 4.0
0.1
1
10
100
0.1
1
10
100
INPUT VOLTAGE (V)
LOAD CURRENT (mA)
LOAD CURRENT (mA)
SHUTDOWN CURRENT vs. INPUT VOLTAGE
MAX856-11
MAX856/MAX857 MAXIMUM OUTPUT CURRENT vs. INPUT VOLTAGE
MAX856-13
MAX858/MAX859 MAXIMUM OUTPUT CURRENT vs. INPUT VOLTAGE
90 80 LOAD CURRENT (mA) 70 60 50 40 30 20 10 0
MAX856-12
1.0 0.9 SHUTDOWN CURRENT (A) 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0 1.5 2.0 2.5 3.0 3.5 TA = -40C TA = +85C TA = +25C
400 350 LOAD CURRENT (mA) 300 250 VOUT = 3.3V 200 150 100 50 0 VOUT = 5.0V
100
VOUT = 3.3V VOUT = 5.0V
4.0
1.0
1.5
2.0
2.5
3.0
3.5
4.0
1.0
1.5
2.0
2.5
3.0
3.5
4.0
INPUT VOLTAGE (V)
INPUT VOLTAGE (V)
INPUT VOLTAGE (V)
4
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MAX856-07
1.6
1.15
MAX858/MAX859 MINIMUM START-UP INPUT VOLTAGE vs. LOAD CURRENT
1.4
3.3V/5V or Adjustable-Output, Step-Up DC-DC Converters
_____________________________Typical Operating Characteristics (continued)
(Circuits of Figure 2, TA = +25C, unless otherwise noted.)
MAX856-MAX859
MAX856/MAX857 LINE-TRANSIENT RESPONSE (5V MODE)
MAX856/MAX857 LOAD-TRANSIENT RESPONSE (5V MODE)
VOUT 50mV/div
VOUT 50mV/div
3V VIN 2V ILOAD 0mA to 100mA
2ms/div
VIN = 2.5V
50s/div
MAX859 LINE-TRANSIENT RESPONSE
MAX858/MAX859 LOAD-TRANSIENT RESPONSE
VOUT 50mV/div
VOUT 50mV/div
3V VIN 2V 1V/div
ILOAD 0mA to 25mA
0 25
1ms/div
VIN = 2.5V
2ms/div
MAX856 START-UP DELAY (5V MODE)
MAX858/MAX859 START-UP DELAY (5V MODE)
VOUT 2V/div
VOUT 2V/div
VSHDN 5V/div
VSHDN 5V/div
VIN = 2.5V, ILOAD = 100mA
5ms/div
VIN = 2.5V, ILOAD = 25mA
5ms/div
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5
3.3V/5V or Adjustable-Output, Step-Up DC-DC Converters MAX856-MAX859
______________________________________________________________Pin Description
PIN MAX856 MAX858 1 2 -- 3 4 5 6 7 8 MAX857 MAX859 1 -- 2 3 4 5 6 7 8 NAME FUNCTION
--- - ---- SHDN - - 3/ 5 FB REF LBO LBI OUT GND LX
Shutdown Input. When low, the entire circuit is off and VOUT = VIN - VD, where VD is the forward voltage drop of the external Schottky rectifier. Selects the output voltage; connect to GND for 5V output, and to OUT for 3.3V output. Feedback Input for adjustable-output operation. Connect to an external resistor voltage divider between OUT and GND. 1.25V Reference Voltage Output. Bypass with 0.22F to GND (0.1F if there is no external reference load). Maximum load capability is 250A source, 20A sink. Low-Battery Output. An open-drain N-channel MOSFET sinks current when the voltage at LBI drops below 1.25V. Low-Battery Input. When the voltage on LBI drops below 1.25V, LBO sinks current. If not used, connect to VIN. Connect OUT to the regulator output. OUT provides bootstrap power to the IC. Power Ground. Must be low impedance; solder directly to ground plane. N-Channel Power-MOSFET Drain
_______________Detailed Description
Operating Principle
The MAX856-MAX859 combine a switch-mode regulator, N-channel power MOSFET, precision voltage reference, and power-fail detector in a single monolithic device. The MOSFET is a "sense-FET" type for best efficiency, and has a very low gate threshold voltage to ensure start-up with low battery voltages (0.8V typ).
PFM Control Scheme
A unique minimum-off-time, current-limited pulse-frequency modulation (PFM) control scheme is a key feature of the MAX856 series (Figure 1). This scheme combines the high output power and efficiency of a pulse-width modulation (PWM) device with the ultra-low quiescent current of a traditional PFM pulse-skipper. There is no oscillator; at heavy loads, switching is accomplished through a constant-peak-current limit in the switch, which allows the inductor current to vary between this peak limit and some lesser value. At light loads, switching frequency is governed by a pair of one-shots, which set a minimum off-time (1s) and a maximum on-time (4s). The switching frequency depends upon the load and the input voltage, and can range up to 500kHz.
6
The peak switch current of the internal MOSFET power switch is fixed at 500mA 100mA (MAX856/MAX857) or 125mA 25mA (MAX858/MAX859). The switch's onresistance is typically 1 (MAX856/MAX857) or 4 (MAX858/MAX859), resulting in a switch voltage drop (VSW) of about 500mV under high output loads. The value of VSW will decrease with light current loads. Conventional PWM converters generate constant-frequency switching noise, whereas the unique architecture of the MAX856-MAX859 produces variable-frequency switching noise. However, unlike conventional pulse-skippers (where noise amplitude varies with input voltage), noise in the MAX856 series does not exceed the switch current limit times the filter-capacitor equivalent series resistance (ESR).
Voltage Reference
The precision voltage reference is suitable for driving external loads, such as an analog-to-digital converter. The voltage-reference output changes less than 2% when sourcing up to 250A and sinking up to 20A. If the reference drives an external load, bypass it with 0.22F to GND. If the reference is unloaded, bypass it with at least 0.1F.
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3.3V/5V or Adjustable-Output, Step-Up DC-DC Converters MAX856-MAX859
MINIMUM OFF-TIME ONE-SHOT VIN Q ONE-SHOT SHDN F/F S R 3/5* GND TRIG ONE-SHOT CURRENT-LIMIT COMPARATOR OUT Q Q N LX VOUT TRIG
MAXIMUM ON-TIME ONE-SHOT
MAX856-MAX859
*
FB**
**
*
ERROR COMPARATOR
**
LBO N LBI COMPARATOR LBI REF
REFERENCE
*MAX856/MAX858 ONLY **MAX857/MAX859 ONLY
Figure 1. Block Diagram
_______________________________________________________________________________________
7
3.3V/5V or Adjustable-Output, Step-Up DC-DC Converters MAX856-MAX859
Logic Inputs and Outputs
The 3/5 input is internally diode clamped to GND and OUT, and should not be connected to signals outside this range. The SHDN input and LBO output (opendrain) are not clamped to V+ and can be pulled as high as 7V regardless of the voltage at OUT. Do not leave control inputs (3/5, LBI, or SHDN) floating. put will follow the battery voltage. This is acceptable in many systems; however, the input or output voltage must not be forced above 7V. The MAX857/MAX859's output voltage is set by two resistors, R1 and R2 (Figure 2b), which form a voltage divider between the output and FB. Use the following equation to determine the output voltage: R1 + R2 VOUT = VREF ( _________ ) R2 where VREF = 1.25V. To simplify resistor selection: VOUT R1 = R2 ( _______ - 1) VREF Since the input bias current at FB has a maximum value of 100nA, large values (10k to 300k) can be used for R1 and R2 with no significant accuracy loss. For 1% error, the current through R1 should be at least 100 times FB's bias current.
__________________Design Procedure
Output Voltage Selection
For the MAX856/MAX858,you can select a 3.3V or 5V - output voltage under logic control, or by tying 3/ 5 to GND or OUT. Efficiency is typically better than 80% over a 2mA to 100mA (MAX856/MAX857) load range. The device is internally bootstrapped, with power derived from the output voltage (via OUT). When the output is in 5V mode, the higher internal supply voltage results in lower switch-transistor on-resistance, slightly greater output power, and higher efficiency. Bootstrapping allows the battery voltage to sag to 0.8V once the system is started. Therefore, the battery voltage ranges from (VOUT + VD) to 0.8V (where VD is the forward drop of the Schottky rectifier). If the battery voltage exceeds the programmed output voltage, the out-
VIN C1* R3 5 R4 8 C1* R3 VOUT C2* 6 2 4 C3 0.1F R1 R4 5 8
VIN
47H L1 D1 1N5817
47H L1 D1 1N5817 VOUT C2* 6 2 4 R2 R1
LBI
LX
LBI
LX
MAX856/MAX858
OUT 1 3 SHDN REF GND 7 3/5 LBO
MAX857/MAX859
OUT 1 3 SHDN REF GND 7 FB LBO
OUTPUT SELECT
C3 0.1F
*C1 = C2 = 68F FOR MAX856 C1 = C2 = 22F FOR MAX858
*C1 = C2 = 68F FOR MAX857 C1 = C2 = 22F FOR MAX859
Figure 2a. Standard Application Circuit--Preset Output Voltage
8
Figure 2b. Standard Application Circuit--Adjustable Output Voltage
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3.3V/5V or Adjustable-Output, Step-Up DC-DC Converters
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 lowbattery monitor's threshold is set by two resistors, R3 and R4 (Figure 2). Set the threshold voltage using the following equation: VLBI R3 = R4 ( ______ - 1) VREF where VLBI is the desired threshold of the low-battery detector and VREF is the internal 1.25V reference. Since the LBI current is less than 100nA, large resistor values (typically 10k to 300k) can be used for R3 and R4 to minimize loading of the input supply. When the voltage at LBI is below the internal threshold, LBO sinks current to GND. Connect a pull-up resistor of 10k or more from LBO to OUT when driving CMOS circuits. When LBI is above the threshold, the LBO output is off. If the low-battery comparator is not used, connect LBI to VIN and leave LBO open.
Capacitor Selection
A 68F, 10V, 0.85, surface-mount tantalum (SMT) output filter capacitor typically provides 50mV output ripple when stepping up from 2V to 5V at 100mA (MAX856/ MAX857). Smaller capacitors (down to 10F with higher ESRs) are acceptable for light loads or in applications that can tolerate higher output ripple. Values in the 10F to 47F range are recommended for the MAX858/MAX859. The equivalent series resistance (ESR) of both bypass and filter capacitors affects efficiency and output ripple. The output voltage ripple is the product of the peak inductor current and the output capacitor's ESR. Use low-ESR capacitors for best performance, or connect two or more filter capacitors in parallel. Low-ESR, SMT tantalum capacitors are currently available from Sprague (595D series) and AVX (TPS series). Sanyo OS-CON organic-semiconductor through-hole capacitors also exhibit very low ESR, and are especially useful for operation at cold temperatures. See Table 1 for a list of suggested capacitor suppliers.
MAX856-MAX859
Rectifier Diode
For optimum performance, a switching Schottky diode (such as the 1N5817) is recommended. Refer to Table 1 for a list of component suppliers. For low output power applications, a PN-junction switching diode (such as the 1N4148) will also work well, although its greater forward voltage drop will reduce efficiency.
Inductor Selection
An inductor value of 47H performs well in most MAX856-MAX859 applications. However, the inductance value is not critical, and the MAX856-MAX859 will work with inductors in the 10H to 100H range. Smaller inductance values typically offer a smaller physical size for a given series resistance, allowing the smallest overall circuit dimensions. However, due to higher peak inductor currents, the output voltage ripple (I PEAK x output filter capacitor ESR) also tends to be higher. Circuits using larger inductance values exhibit higher output current capability and larger physical dimensions for a given series resistance. The inductor's incremental saturation current rating should be greater than the peak switch-current limit, which is 500mA for the MAX856/MAX857, and 125mA for the MAX858/MAX859. However, it is generally acceptable to bias the inductor into saturation by as much as 20%, although this will slightly reduce efficiency. The inductor's DC resistance significantly affects efficiency. See the Efficiency vs. Load Current for Various Inductors graph in the Typical Operating Characteristics. See Tables 1 and 2 for a list of suggested inductor suppliers.
PC Layout and Grounding
The MAX856 series' high-frequency operation makes PC layout important for minimizing ground bounce and noise. Keep the IC's GND pin and the ground leads of C1 and C2 (Figure 1) less than 0.2in (5mm) apart. Also keep all connections to the FB and LX pins as short as possible. To maximize output power and efficiency and minimize output ripple voltage, use a ground plane and solder the IC's GND (pin 7) directly to the ground plane.
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9
3.3V/5V or Adjustable-Output, Step-Up DC-DC Converters MAX856-MAX859
Table 1. Component Suppliers
PRODUCTION METHOD INDUCTORS CAPACITORS Matsuo 267 series Sprague 595D series AVX TPS series RECTIFIERS
Surface Mount
See Table 2
Motorola MBR 0530 Nihon EC15QS02L
Miniature Through Hole
Sumida RCH654-220
Sanyo OS-CON series low-ESR organic semiconductor Maxim MAXC001 150F, low-ESR electrolytic Nichicon PL series low-ESR electrolytic United Chemi-Con LXF series Motorola 1N5817
Low-Cost Through Hole
Renco RL 1284-22 CoilCraft PCH-27-223
COMPANY AVX CoilCraft Coiltronics Matsuo Motorola Murata-Erie Nichicon Nihon Renco Sanyo Sumida TDK United Chemi-Con
PHONE USA: (207) 282-5111 USA: (708) 639-6400 USA: (407) 241-7876 USA: (714) 969-2491 USA: (408) 749-0510 (800) 521-6274 USA: (800) 831-9172 USA: (708) 843-7500 USA: (805) 867-2555 Japan: 81-3-3494-7411 USA: (516) 586-5566 USA: (619) 661-6835 Japan: 81-7-2070-6306 USA: (708) 956-0666 Japan: 81-3-3607-5111 USA: (708) 803-6100 Japan: 03-3278-5111 USA: (714) 255-9500
FAX (207) 283-1941 (708) 639-1469 (407) 241-9339 (714) 960-6492
(404) 684-1541 (708) 843-2798 (805) 867-2556 81-3-3494-7414 (516) 586-5562 (619) 661-1055 81-7-2070-1174 (708) 956-0702 81-3-3607-5144 (708) 803-6294 03-3278-5358 (714) 255-9400
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3.3V/5V or Adjustable-Output, Step-Up DC-DC Converters MAX856-MAX859
Table 2. Surface-Mount Inductor Information
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 INDUCTANCE (mH) 47 47 47 22 22 47 22 22 47 20 22 RESISTANCE (W) 0.14 0.27 0.85 0.38 0.94 1.5 3.1 1.15 2.25 0.175 0.16 RATED CURRENT (A) 1.0 0.8 0.540 0.760 0.320 0.220 0.85 0.210 0.150 1.15 0.500 HEIGHT (mm) 5.0 4.5 3.2 3.2 2.6 2.6 1.8 2.2 2.2 4.2 3.2
__Ordering Information (continued)
PART MAX858CSA MAX858CUA MAX858C/D MAX858ESA MAX858MJA MAX859CSA MAX859CUA MAX859C/D MAX859ESA MAX859MJA TEMP. RANGE 0C to +70C 0C to +70C 0C to +70C -40C to +85C -55C to +125C 0C to +70C 0C to +70C 0C to +70C -40C to +85C -55C to +125C PIN-PACKAGE 8 SO 8 MAX Dice* 8 SO 8 CERDIP 8 SO 8 MAX Dice* 8 SO 8 CERDIP
___________________Chip Topography
LX
SHDN
3/5 OR FB*
GND
0.084" (2.1336mm)
REF OUT
* Dice are tested at TA = +25C only. Contact factory for availability.
LBO
LBI
0.058" (1.4732mm) *3/5 FOR MAX856/MAX858; FB FOR MAX857/MAX859.
TRANSISTOR COUNT: 357; SUBSTRATE CONNECTED TO OUT.
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3.3V/5V or Adjustable-Output, Step-Up DC-DC Converters MAX856-MAX859
________________________________________________________Package Information
DIM
C A 0.101mm 0.004 in B A1 L
e
A A1 B C D E e H L
INCHES MAX MIN 0.044 0.036 0.008 0.004 0.014 0.010 0.007 0.005 0.120 0.116 0.120 0.116 0.0256 0.198 0.188 0.026 0.016 6 0
MILLIMETERS MIN MAX 0.91 1.11 0.10 0.20 0.25 0.36 0.13 0.18 2.95 3.05 2.95 3.05 0.65 4.78 5.03 0.41 0.66 0 6
E
H
8-PIN MAX MICROMAX SMALL OUTLINE PACKAGE
D
DIM
D A e B
0.101mm 0.004in.
0-8
A1
C
L
A A1 B C E e H L
INCHES MAX MIN 0.069 0.053 0.010 0.004 0.019 0.014 0.010 0.007 0.157 0.150 0.050 0.244 0.228 0.050 0.016
MILLIMETERS MIN MAX 1.35 1.75 0.10 0.25 0.35 0.49 0.19 0.25 3.80 4.00 1.27 5.80 6.20 0.40 1.27
E
H
Narrow SO SMALL-OUTLINE PACKAGE (0.150 in.)
DIM PINS D D D 8 14 16
INCHES MILLIMETERS MIN MAX MIN MAX 0.189 0.197 4.80 5.00 0.337 0.344 8.55 8.75 0.386 0.394 9.80 10.00
21-0041A
12
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