View SP6641BEK-33TR_156500.PDF datasheet online --- IC-ON-LINE

Datasheet File OCR Text:

(R)
SP6641A/6641B
500mA Alkaline DC/DC Boost Regulator in SOT-23
s Ultra Low Quiescent Current: 10A s Wide Input Voltage Range: 0.9V to 4.5V s 90mA IOUT at 1.3V Input (SP6641A-3.3V) s 500mA IOUT at 2.6V Input (SP6641B-3.3V) s 100mA IOUT at 2.0V Input (SP6641A-5.0V) s 500mA IOUT at 3.3V Input (SP6641B-5.0V) s Fixed 3.3V or 5.0V Output Voltage s Up to 87% Efficiency s 0.3 NFET RDSon s Startup Voltage Guaranteed at 0.9V s 0.33A Inductor Current Limit (SP6641A) s 1A Inductor Current Limit (SP6641B) s Logic Shutdown Control s SOT-23-5 Package
LX 1
5 VBATT
SP6641
GND 2
5 Pin SOT-23
VOUT 3 4 SHDN
APPLICATIONS s PDA's s DSC's s CD/MP3 Players s Pagers s Digital Cameras s Portable Handheld Medical Devices
DESCRIPTION The SP6641 is an ultra-low quiescent current, high efficiency, DC-DC boost converter designed for single and dual cell alkaline, or Li-ion battery applications found in PDA's, MP3 players, and other handheld portable devices. The SP6641 features a 10A quiescent current, a 0.3 Nchannel charging switch, 0.9V input startup, and a 0.33A or 1.0A inductor current limiting feature. The SP6641 is offered in a 5 pin SOT-23 package and provides an extremely small power supply footprint optimized for portable applications. The SP6641 is preset to 3.3V and can be controlled by a 1nA active LOW shutdown pin.
L1
0.9V to 4.5V VBATT VBATT 5
(R)
1 LX D1 2 GND 3 VOUT R1 C3
C1
U1 SP6641A SHDN SHDN
IOUT (mA)
4
C2
VOUT +3.3V or 5V
SP6641A 3.3V & 5V: C1 = C2 = 22F Ceramic, L1 = 22H CDRH5D28, D1 = MBR0520, C3 = Open, R1 = Shorted. SP6641B 3.3V & 5V: C1 = C2 = 100F POSCAP, L1 = 10H CDRH5D28, D1 = ZHCS2000, C3 = 1F Ceramic, R1 = 10.
700 650 600 550 500 450 400 350 300 250 200 150 100 50 0 1.0
SP6641B, 1.0A, 3.3V SP6641B, 1.0A, 5V SP6641A, 0.33A, 3.3V SP6641A, 0.33A, 5V
1.5
2.0
2.5
3.0
3.5
4.0
4.5
VIN (V)
Figure 1. Typical Application Schematic
Rev. 3/5/02, *Patent Pending
Figure 2. Maximum Load Current in Operation
(c) Copyright 2002 Sipex Corporation
SP6641A/6641B 500mA Alkaline DC/DC Boost Regulator in SOT-23
1
ABSOLUTE MAXIMUM RATINGS
These are stress ratings only and functional operation of the device at these ratings or any other above those indicated in the operation sections of the specifications below is not implied. Exposure to absolute maximum rating conditions for extended periods of time may affect reliability. LX, VOUT, SHDN, VBATT to GND pin ....... -0.3 to 6.0V LX Current .......................................................... 1.5A Reverse VBATT Current ................................... 220mA Storage Temperature ........................ -65C to 150C Operating Temperature ..................... -40C to +85C Lead Temperature (Soldering, 10 sec) .......... 300 C
ELECTRICAL SPECIFICATIONS
VBATT = VSHDN = 1.3V, ILOAD = 0mA, -40C Rev. 3/5/02, *Patent Pending
SP6641A/6641B 500mA Alkaline DC/DC Boost Regulator in SOT-23
(c) Copyright 2002 Sipex Corporation
2
PIN DESCRIPTION
PIN NO. 1 PIN NAME LX DESCRIPTION Inductor switching node. Connect one terminal of the inductor to the positive terminal of the battery. Connect the second terminal of the inductor to this pin. The inductor charging current flows into LX, through the internal charging N-channel FET, and out through the GND pin. Ground pin. The internal regulator bias currents and the inductor charging current flows out of this pin. Output voltage sense pin, internal regulator voltage supply, and minimum off-time one shot input. Kelvin connect this pin to the positive terminal of the output capacitor, but for SP6641B, use 10 series resistor and 1F bypass per Figure 1 schematic. Shutdown. Tie this pin to VBATT for normal operation. Tie this pin the ground to disable all circuitry inside the chip. In shutdown mode, the output voltage will float at a diode drop below the battery potential. Battery voltage pin. The startup circuitry runs off of this pin. The regulating circuitry also uses this voltage to control the minimum offtime. TOFF KOFF / (VOUT - VIN).
2 3
GND VOUT
4
SHDN
5
VBATT
BLOCK DIAGRAM
VBATT VOUT
VBATT
LX
Internal VBATT
VBATT VOUT LOAD SU EN OSC VOUT VBATT R TOFF Q CHARGE NGATE M VOUT 1 DRIVER LX
+
SUGATE IPK/M
ITH
C
-
ICHN
SHDN
SHDN
Min. TOFF
VOUT
GND REFREADY SHDN Ref Block Internal Ground
+
REF FB
C
-
VOUT(LOW) Qn S
VOUT
SP6641
Internal Supply
Rev. 3/5/02, *Patent Pending
SP6641A/6641B 500mA Alkaline DC/DC Boost Regulator in SOT-23
(c) Copyright 2002 Sipex Corporation
3
PERFORMANCE CHARACTERISTICS
Refer to the circuit in Figure 1, TAMB = +25C
100 95 90
VIN = 3.0V VIN = 2.6V VIN = 2.0V VIN = 1.3V VIN = 1.0V
100 95 90
VIN = 3.0V VIN = 2.6V VIN = 2.0V VIN = 1.3V VIN = 1.0V
Efficiency (%)
0.1 1.0 10.0 100.0 1000.0
Efficiency (%)
85 80 75 70 65 60
85 80 75 70 65 60 0.1 1.0 10.0 100.0 1000.0
Iload (mA)
Iload (mA)
Figure 3. SP6641AEK - 3.3 Efficiency vs Load Current
Figure 4. SP6641BEK - 3.3 Efficiency vs Load Current
3.400 3.380 3.360 3.340 3.320
VOUT
VIN = 3.0V VIN = 2.6V VIN = 2.0V VIN = 1.3V VIN = 1.0V
3.400 3.380 3.360 3.340 3.320
3.300 3.280 3.260 3.240 3.220 3.200 0 50 100 150 Iload (mA) 200 250
VOUT
3.300 3.280 3.260 3.240 3.220 3.200 0 200 400 Iload (mA) 600 800
VIN = 3.0V VIN = 2.6V VIN = 2.0V VIN = 1.3V VIN = 1.0V
Figure 5. SP6641AEK - 3.3 Line/Load Rejection vs Load Current
Figure 6. SP6641BEK - 3.3 Line/Load Rejection vs Load Current
100 95 90
100 95 90 Efficiency (%) 85 80 75 70 65 60 0.1
Vi=4.2V Vi=3.6V Vi=3.3V Vi=2.0V Vi=1.3V
Efficiency (%)
85 80 75 70 65 60 0.1
Vi=4.2V Vi=3.6V Vi=3.3V Vi=2.0V Vi=1.3V
1.0
10.0 Iload (mA)
100.0
1000.0
1.0
10.0 Iload (mA)
100.0
1000.0
Figure 7. SP6641AEK-5.0 Efficiency Vs Load Current
Figure 8. SP6641BEK-5.0 Efficiency Vs Load Current
Rev. 3/5/02, *Patent Pending
SP6641A/6641B 500mA Alkaline DC/DC Boost Regulator in SOT-23
(c) Copyright 2002 Sipex Corporation
4
PERFORMANCE CHARACTERISTICS
Refer to the circuit in Figure 1, TAMB = +25C
5.200 5.180 5.160 5.140
Vo (V)
5.100
Vi=4.2V Vi=3.6V Vi=3.3V Vi=2.0V Vi=1.3V
Vo (V)
5.080 5.060 5.040 5.020 5.000 4.980 4.960 4.940 4.920 Vi=4.2V Vi=3.6V Vi=3.3V Vi=2.0V Vi=1.3V 200 400 Iload (mA) 600 800
5.120 5.100 5.080 5.060 5.040 5.020 5.000 0 50 100 150 Iload (mA) 200 250
4.900 0
Figure 9. SP6641AEK-5.0 Line/Load Rejection Vs Load Current
Figure 10. SP6641BEK-5.0 Line/Load Rejection Vs Load Current
250 SP6641AEK-5.0 SP6641AEK-3.3
500 450 SP6641B-5.0 SP6641B-3.3
200
400 350
Iin (uA)
Iin (uA)
150
300 250 200 150
100
50
100 50
0 0.5
1.0
1.5
2.0
2.5 Vin (V)
3.0
3.5
4.0
4.5
0 0.5
1.0
1.5
2.0
2.5 Vin (V)
3.0
3.5
4.0
4.5
Figure 11. SP6641AEK-3.3 & SP6641AEK-5.0 No Load Battery Current
Figure 12. SP6641BEK-3.3 & SP6641AEK-5.0 No Load Battery Current
250
700 600 500
200
Io (mA)
Io (mA)
SP6641AEK-3.3, 22H SP6641AEK-3.3, 10H
150
400 300 200 100 0 0.5
SP6641BEK-3.3, 22H SP6641BEK-3.3, 10H SP6641BEK-5.0, 22H SP6641BEK-5.0, 10H
100
50
SP6641AEK-5.0, 22H SP6641AEK-5.0, 10H
0 0.5
1.0
1.5
2.0
2.5 Vin (V)
3.0
3.5
4.0
4.5
1.0
1.5
2.0
2.5 Vin (V)
3.0
3.5
4.0
4.5
Figure 13. SP6641AEK-3.3 & SP6641AEK-5.0 Maximum Resistive Load Current in Startup
Rev. 3/5/02, *Patent Pending
Figure 14. SP6641BEK-3.3 & SP6641BEK-5.0 Maximum Resistive Load Current in Startup
(c) Copyright 2002 Sipex Corporation
SP6641A/6641B 500mA Alkaline DC/DC Boost Regulator in SOT-23
5
OPERATION General Overview The SP6641 is a high efficiency, low quiescent current step-up DC-DC converter ideal for single and dual cell alkaline and single cell Lithium Ion battery applications such as medical monitors, PDA's, MP3 players, and other portable end products. The SP6641's 10A quiescent current, low 0.3 NFET switch, and unique PFM control scheme combine to provide excellent efficiency over a wide output power range. Other features include a logic level enable control pin, guaranteed 0.9V startup, a tiny SOT23 5 pin package, and precise inductor peak current control. SP6641A sources up to 90mA at 1.3V, typ. and SP6641B sources up to 500mA at 2.6V, typ. by supporting different peak inductor current levels. Only two capacitors, an inductor, and a diode are required to build a power supply for the SP6641A. The SP6641B, 1A peak current requires an additional small resistor and capacitor as a low pass filter for the VOUT IC power pin. Loop Regulation The SP6641 combines a fixed inductor peak current limit, a feed-forward minimum off-time one-shot, and a precision loop comparator to regulate the output voltage. Under light-load conditions the loop operates as a standard PFM converter. The frequency of fixed amplitude inductor current triangles is modulated to regulate the load. Under heavy load conditions, the converter adjusts the number of successive continuous mode current pulses to regulate the load. Refer to the block diagram for the following explanation of operating modes in loop regulation. The output voltage is internally divided down and fed to the negative terminal of the loop comparator. A +1.25V bandgap reference voltage is applied to the positive terminal of the comparator. As the output voltage droops below the regulation threshold due to the load the loop comparator output (signal VOUT(LOW)) transitions to a logic "1". This sets the SR latch and initiates inductor charging by pulling the signal NGATE high. Inductor charging continues until the current reaches the internally programmed limit, at which point, the off-time one-shot is triggered. The off-time one-shot via signal TOFF resets the SR latch regardless of the SET state (VOUT(LOW)), opens the NMOS charge switch, and forces the
Rev. 3/5/02, *Patent Pending
inductor to discharge through the rectifying diode for a minimum time defined by the oneshot duration. The end of the off-time pulse releases the SR latch, and its output state is once again determined by the output of the loop comparator (VOUT(LOW)). Under light load conditions, the output voltage will have been pulled above the regulation threshold during the minimum off-time, the signal VOUT(LOW) will be a logic "0", and the NMOS charging switch will remain open. The inductor current discharges until it reaches zero or the loop comparator triggers a new charge cycle. Under a heavy load, the output voltage will remain below the regulation point at the end of the off-time pulse. In this condition, VOUT(LOW) has a logic value of 1 which immediately starts a new charge/discharge cycle defined by the peak inductor current and the minimum offtime. The inductor current will remain in a continuous conduction mode until the loop comparator indicates the output voltage is above the regulation threshold, and the inductor current will relax towards zero. During continuous mode bursts, the inductor current frequency and ripple amplitude are controlled by the minimum off-time one-shot and the input and output voltage levels. The SP6641 sets the minimum off-time to: KOFF TOFF = (VOUT - VIN), where: KOFF VOUT VIN = Off-time Constant, typically 1.5s*V = Output Voltage = Input Voltage
Plugging the TOFF expression into the boost mode equations yields the maximum output current in regulation: VIN K IOUT(MAX) IPK - OFF VOUT 2L where: = Efficiency, typically 0.80 to 0.90 IPK = Programmed inductor peak current, typically 0.33A for the SP6641A, typically 1.0A for the SP6641B. L = Inductor value
( )(
)
SP6641A/6641B 500mA Alkaline DC/DC Boost Regulator in SOT-23
(c) Copyright 2002 Sipex Corporation
6
OPERATION Loop Regulation: continued The SP6641 feed forward off-time control delivers more load current than constant off-time control because the input battery voltage drops during its life cycle. The term (IPK - KOFF/2L) is the average current delivered to the output capacitor during the discharge phase. This is constant with respect to input and output voltage. With constant off-time control, the average discharge current term becomes (IPK-TOFF*(VOUT-VIN)/2L), which decreases as the input voltage drops. Table 1 illustrates the average inductor current delivered to the load during discharge versus the input voltage. The SP6641 feed forward offtime control and the constant off-time control are compared. For purposes of illustration, the off times of each control scheme are normalized at a typical two cell alkaline input voltage of 2.6V. The values used in Table 1 are: IPK = 0.33A L = 22H VOUT= 3.3V TOFF (SP6641) = 1.5V*s/(3.3-VIN) TOFF (constant) = 2.14s SP6641A VIN 3.0 2.6 2.0 1.3 1.0 TOFF 5.00s 2.14s 1.15s 0.75s 0.65s Avg IL 0.30A 0.30A 0.30A 0.30A 0.30A Constant TOFF TOFF 2.14s 2.14s 2.14s 2.14s 2.14s Avg IL 0.32A 0.30A 0.27A 0.23A 0.22A Ignoring the conduction losses of VD and VC, the burst frequency equation simplifies to: (VOUT - VIN)VIN FBURST = KOFFVOUT Startup The internal regulator circuitry is bootstrapped to the VOUT pin. This requires a low voltage oscillator and charging switch powered from the VBATT pin to pump up the output voltage until the reference is established. The reference provides a REFREADY signal that determines when output control is handed over to the regulator. REFREADY shuts down the startup circuit and enables the regulator when the reference is valid and VOUT is above +1.9V. Once the regulator is given control it will continue to pump up the output at full power until regulation is reached. For two cell alkaline input voltages and above, the output voltage will be pulled above +1.9V quickly through the rectifying diode before the reference has a chance to establish. In this scenario the startup circuit will coarsely regulate around +2.8V until the REFREADY signal asserts. This keeps the output from overshooting in startup with higher input voltages. Startup is guaranteed at +0.9V at room temperature with a 3k load. Heavier loads will require a higher input voltage. Shutdown/Enable Control Pin 4 of the device is a VBATT referred control pin that shuts down the converter with the pin tied to ground, or enables the converter with the pin tied to VBATT. When the converter is shutdown the power switch is opened and all circuit biasing is extinguished leaving only junction leakage currents on supply pins 3 and 5. The output voltage will droop to one diode drop below the battery voltage through the rectifying diode. After pin 4 is brought high, the startup circuit is enabled and starts pumping up the output until REFREADY hands over control to the internal regulator.
Table 1- Average IL vs. Input Voltage
The following equation defines the burst mode frequency under heavy load conditions: FBURST = VOUT - VIN KOFF
(
)(
VIN - VC VOUT + VD -VC
)
where: VD = Forward schottky drop, (0.4V, typ) VC = Average charging switch drop, Rnmos*IPK, typically 0.1V
Rev. 3/5/02, *Patent Pending
SP6641A/6641B 500mA Alkaline DC/DC Boost Regulator in SOT-23
(c) Copyright 2002 Sipex Corporation
7
APPLICATION INFORMATION Circuit Layout Printed circuit board layout is a critical part of a power supply design. Poor designs can result in excessive EMI on the voltage gradients and feedback paths on the ground planes with applications involving high switching frequencies and large peak currents. Excessive EMI can result in instability or regulation errors. All power components should be placed on the PC board as closely as possible with the traces kept short, direct, and wide (>50mils or 1.25mm). Extra copper on the PC board should be integrated into ground as a pseudo-ground plane. On a multilayer PC board, route the star ground using component-side copper fill, then connect it to the internal ground plane using vias. For the SP6641A/6641B devices, input and output filter capacitors should be soldered with their ground pins as close together as possible in a star-ground configuration. The VOUT pin must be bypassed directly to ground as close to the SP6641A/6641B devices as possible (within 0.2in or 5mm). The DC-DC converter and any digital circuitry should be placed on the opposite corner of the PC board as far away from sensitive RF and analog input stages. Noisy traces, such as from the LX pin, should be kept away from the voltage-feedback VOUT node and separated from it using grounded copper to minimize EMI. See the SP6641A/6641B Evaluation Board Manual for PC Board Layout design details. Component Selection Selection of capacitors, inductors and schottky diodes for SP6641A and SP6641B power supply circuits can be made through the use of Table 1 component selection. Capacitor equivalent series resistance is a major contributor to output ripple, usually greater than 60%. Low ESR capacitors are recommended. Ceramic capacitors have the lowest ESR. Low-ESR tantalum capacitors may be a more acceptable solution having both a low ESR and lower cost than large ceramic capacitors. Designers should select input and output capacitors with a rating exceeding the peak inductor current. Do not allow tantalum capacitors to exceed their ripplecurrent ratings. For example, in the SP6641A a 22F, 6V, low-ESR, surface-mount tantalum output filter capacitor typically provides 60mV output ripple when stepping up from 1.3V to 3.3V at 20mA. An input filter capacitor can reduce peak currents drawn from the battery and improve efficiency. Low-ESR aluminum electrolytic capacitors are acceptable in some applications but standard aluminum electrolytic capacitors are not recommended. In selecting an inductor, the saturation current specified for the inductor needs to be greater then the SP6641A/B peak current to avoid saturating the inductor, which would result in a loss in efficiency and could damage the inductor. The SP6641A evaluation board uses a Sumida CDRH5D28 22H inductor with an Isat value of 0.9A and a DCR of 0.095, which easily handles the Ipeak of 0.33A of the SP6641A and will deliver high efficiencies. The SP6641B evaluation board uses a Sumida CDRH5D28 10H inductor with an Isat value of 1.3A and a DCR of 0.065, which easily handles the Ipeak of 1.0A of the SP6641B and will deliver high efficiencies. Other inductors could be selected provided their Isat is greater than the Ipeak of the SP6641A/SP6641B. Output Filter or LDO Regulator Designers could add LC pi filters, linear postregulators, or shielding in applications necessary to address excessive noise, voltage ripple, or EMI concerns. The LC pi filter's cutoff frequency should be at least a decade or two below the DC-DC converters' switching frequency for the specified load and input voltage. The SP6201, a small SOT235pin 200mA Low Drop Out linear regulator can be used at the SP6641A/6641B output to reduce output noise and ripple. The schematic in figure 15 illustrates this circuit on the SP6641A Evaluation Board with the SP6641 3.3V output followed by the Sipex SP6201 3.0V output Low Drop Out linear regulator.
Rev. 3/5/02, *Patent Pending
SP6641A/6641B 500mA Alkaline DC/DC Boost Regulator in SOT-23
(c) Copyright 2002 Sipex Corporation
8
APPLICATION INFORMATION: continued Maximum Startup Current It should be noted that for low input voltages the SP6641 startup circuit can not support large load currents at startup. In startup the SP6641 needs to boost the output from zero volts using a charge pump which has a limited current capacity. Once the output is greater than 1.7 to 1.9V the operate circuit takes over and the SP6641 can supply much more current. Curves of maximum resistive load current in startup for the SP6641A and SP6641B are shown in Figures 13 & 14 and can be compared with Figure 2, maximum load current in operation. Also, Table 2 provides SP6641A 3.3V resistive load current in startup for some low cost 1812 size chip inductors. TABLE 1. COMPONENT SELECTION
INDUCTORS - SURFACE MOUNT
Inductor Specification
Sipex Part Number Inductance (H) Manufacturer/ Part Number Series R () Isat (A) Size LxWxH (mm) Inductor Type Manufacturer Website
From the curves in Figures 13 and 14, you can see that for low input voltages, the 22H inductor has more current capacity at startup than the 10H inductor, due to more energy per charge cycle in the relationship 1/2LI2. Thus for 1 cell applications, 22H is recommended for more startup current than 10H. For 1-cell battery applications, it is recommended to apply any large load current after the SP6641 has started up, typically in a few millisecs. This is typically not a problem in many applications where the load is a processor whose load current is low until the processor voltage comes up.
SP6641A Ipk = .33A SP6641A Ipk = .33A SP6641A Ipk = .33A SP6641A Ipk = .33A SP6641B Ipk = 1A SP6641B Ipk = 1A SP6641B Ipk = 1A SP6641B Ipk = 1A SP6641B Ipk = 1A
22 22 22 22 10 10 10 22 22
Sumida CDRH5D28-220 Coilcraft DO1608C-223 TDK NLC453232T-220 Murata LQH43C220K04 Sumida CDRH5D28-100 Coilcraft DO1608C-103 Sumida CDRH6D28-220
0.095 0.370 0.900 0.600 0.065 0.160 0.128
0.90 0.70 0.37 0.42 1.30 1.10 1.70 1.20 1.20
5.7x5.5x3 6.6x4.5x2.9 4.4x3.2x3.2 4.5x3.2x2.6 5.7x5.5x3 6.6x4.5x2.9 5x5x4.7 6.7x6.5x3 5x5x4.7
Shielded Ferrite Core Unshielded Ferrite Core Unshielded Ferrite Core Unshielded Ferrite Core Shielded Ferrite Core Unshielded Ferrite Core Unshielded Ferrite Core Shielded Ferrite Core Unshielded Ferrite Core
www.sumida.com www.coilcraft.com www.tdk.com www.murata.com www.sumida.com www.coilcraft.com www.murata.com www.sumida.com www.murata.com
Murata LQH55DN100M01 0.077 Murata LQH55DN220M01 0.160
CAPACITORS - SURFACE MOUNT & THRU-HOLE
Capacitor Specification
Sipex Part Number Capacitance (F) Manufacturer/ Part Number ESR (max) () Ripple Current @ 45C (A) Size LxWxH (mm) Voltage (V) Capacitor Type Manufacturer Website
SP6641A Ipk = .33A SP6641B Ipk = 1A SP6641B Ipk = 1A
22 100 100
TDK C3225X5R0J226M 0.010 SANYO 10TPA100M SANYO 16SA100M 0.080 0.030
4.00 1.20 2.70
1210 7343 8Dx10L
6.3 6.3 16.0
SMT X5R Cer. Thru-hole OS-CON
www.tdk.com www.sanyovideo.com
SMT POSCAP Tant. www.sanyovideo.com
SCHOTTKY DIODE - SURFACE MOUNT
Diode Specification
Sipex Part Number Manufacturer/ Part Number VF @ IF (V) IF(AV) (A) Size LxWxH (mm) Reverse V (V) Package Type Manufacturer Website
SP6641A Ipk = .33A SP6641B Ipk = 1A
STMicro STPS0520Z Zetex ZCHS2000
0.39 0.42
0.50 2.00
3.9x1.7x1.3 3x3x1.4
20 40
SOD-123 SOT23-6
www.st.com www.zetex.com
Note: Components highlighted in bold are those used on the SP6641A or SP6641B Evaluation Board.
Rev. 3/5/02, *Patent Pending
SP6641A/6641B 500mA Alkaline DC/DC Boost Regulator in SOT-23
(c) Copyright 2002 Sipex Corporation
9
APPLICATION INFORMATION: continued
+0.9V to +3.3V Input VBATT C1 22F L1 22H
(R)
+
VOUT +3.0V 1 2 1 2 3 VOUT +3.3V J1 3 VIN GND SP6201 RESET 4
(R)
1 2 D1 3
U1 VBATT 5 SP6641 GND LX VOUT SHDN 4
VOUT 5 C3 1F
ENABLE
C2 + 22F
Figure 15. SP6641A 3.3V Evaluation Board with SP6201 LDO Regulator
SuperCap Application on the SP6641 Output When the battery input to SP6641A is removed, the SP6641A output will end up in the charge mode and will slowly discharge a Supercap connected to the output. The typical Supercap of 0.22F will go from fully charged at 3.3V to less than 2V in 5 minutes. The following appli-
cation circuit in figure 16 is recommended to disconnect the SP6641 output from the SuperCap when the battery is removed. The small SOT233pin MOS switches are an inexpensive addition to the SP6641 circuit and work well to maintain SuperCap voltage to retain Non-Volatile CMOS Memory while a battery is changed.
TABLE 2. SP6641A Resistive Load Current in Startup - low cost inductors
SP6641A APPLICATION CIRCUIT WITH PANASONIC INDUCTOR L1 = ELJ-PB220KF 22H, IDCmax = 300mA, DCR = 1.0 Startup Load ROUT (min) VOUT after Startup V IOUT after Startup mA Startup then Load mA (max) SP6641A APPLICATION CIRCUIT WITH TDK INDUCTOR L1 = NLC453232T-220K 22H, IDCmax = 370mA, DCR = 0.9 Startup Load ROUT (min) VOUT after Startup V IOUT after Startup mA Startup then Load mA (max)
VIN V
VIN V
0.86 0.88 0.90 0.95 1.00 1.10 1.20 1.30 1.40 1.50
16000 1500 800 230 125 73 58 50 43 39
3.31 3.31 3.30 3.30 3.30 3.29 3.29 3.28 3.28 3.28
0.2 2 4 14 26 45 57 66 76 84
37 39 40 44 48 56 63 71 78 86
0.86 0.88 0.90 0.95 1.00 1.10 1.20 1.30 1.40 1.50
16000 1500 900 260 126 66 49 43 39 36
3.30 3.30 3.30 3.30 3.30 3.29 3.29 3.29 3.29 3.29
0.2 2 4 13 26 50 67 77 84 91
42 43 44 48 52 60 69 77 84 91
Rev. 3/5/02, *Patent Pending
SP6641A/6641B 500mA Alkaline DC/DC Boost Regulator in SOT-23
(c) Copyright 2002 Sipex Corporation
10
APPLICATION INFORMATION: continued Low Battery Circuit for SP6641 Application The circuit in figure 17 uses the Sipex SPX432 shunt regulator as a reference and comparator circuit to detect a low battery condition and give a high level, typically 1.7V output. When the battery is good, the SPX432 output is low, but not at ground but at 0.8V or about one Vbe below the 1.24V reference. To translate that level to a CMOS Low of less than 0.4V, an NPN and 2 signal diodes can be added to the SPX432
VBATT C1 22F
output, as shown. The small SOT23-3pin SPX432 and 2N3904 bipolar transistor and diodes are small and inexpensive to add to the SP6641 circuit and work well to add a Battery Low detection circuit, with the addition of about 130A current from 3.3V out. As a bonus, the output of this circuit can be used to drive the SP6641 SHDN_N pin 3 to GND when the battery is removed, which would reset the SP6641 and eliminate the need for the SuperCap Switch shown in figure 16.
L1 22H
(R)
VOUT +3.3V 5 SHDN J1 1 2 3
2.7V, 0.9 PMOS SOT23-3 IRLML6302 3 Q1 2 R1 1M 1 3 1
3.3V to Nonvolatile Function
1
LX
VBATT
2 Diode Schottky 3
U1 SP6641
GND VOUT SHDN 4
C3 .22F Supercap
Q2 SOT23-3 IRLML2402 2.7V NMOS 2
C2 22F
Figure 16. SP6641A 3.3V with SuperCap Switch
VBATT C1 22F
1.8V THRES. R1 44k
1
VTHRES = 1.24V(1 + R1/R2)
U2 SPX432M
REF
L1 22H
R2 100k
2 K SOT23-3
A3
BATT GOOD R4 D2 D3 2V = BATT GOOD Q2 0V = LOW BATT 2N3904 R5 100k VOUT 3.3V
1 LX 2 GND
(R)
VBATT 5
D1 Diode Schottky C2 22F
U1 SP6641
SHDN 4
100k R3 20k
1N4148 1N4148
3V OUT
Figure 17. SP6641A 3.3V with Low Battery Detection
Rev. 3/5/02, *Patent Pending SP6641A/6641B 500mA Alkaline DC/DC Boost Regulator in SOT-23 (c) Copyright 2002 Sipex Corporation
11
PACKAGE: 5 Lead SOT23
b C L e
E
e1 D C L A A2
A
C L a 0.20
DATUM 'A'
C A1
A .10
E1
L
2
SYMBOL A A1 A2 b C D E E1 L e e1 a
MIN 0.90 0.00 0.90 0.25 0.09 2.80 2.60 1.50 0.35 0.95ref 1.90ref 0
O
MAX 1.45 0.15 1.30 0.50 0.20 3.10 3.00 1.75 0.55
10
O
Rev. 3/5/02, *Patent Pending
SP6641A/6641B 500mA Alkaline DC/DC Boost Regulator in SOT-23
(c) Copyright 2002 Sipex Corporation
12
ORDERING INFORMATION
Part Number TOP MARK Temperature Range SP6641AEK-3.3/TR ............. K1 ...................... -40C to 85C ........ SP6641BEK-3.3/TR ............. L1 ...................... -40C to 85C ........ SP6641AEK-5.0/TR ............. P1 ...................... -40C to 85C ........ SP6641BEK-5.0/TR ............. Q1 ...................... -40C to 85C ........ Package Type (Tape & Reel) 5-Pin SOT-23 (Tape & Reel) 5-Pin SOT-23 (Tape & Reel) 5-Pin SOT-23 (Tape & Reel) 5-Pin SOT-23
Corporation
SIGNAL PROCESSING EXCELLENCE
Sipex Corporation Headquarters and Sales Office 22 Linnell Circle Billerica, MA 01821 TEL: (978) 667-8700 FAX: (978) 670-9001 e-mail: sales@sipex.com Sales Office 233 South Hillview Drive Milpitas, CA 95035 TEL: (408) 934-7500 FAX: (408) 935-7600
Sipex Corporation reserves the right to make changes to any products described herein. Sipex does not assume any liability arising out of the application or use of any product or circuit described herein; neither does it convey any license under its patent rights nor the rights of others.
Rev. 3/5/02, *Patent Pending
SP6641A/6641B 500mA Alkaline DC/DC Boost Regulator in SOT-23
(c) Copyright 2002 Sipex Corporation
13

▲Up To Search▲

Price & Availability of SP6641BEK-33TR

	To Download SP6641BEK-33TR Datasheet File
If you can't view the Datasheet, Please click here to try to view without PDF Reader .