Introducing Worlds' Simplest Surface Mount Switcher! Micrel's Sup
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Introducing Worlds' Simplest Surface Mount Switcher!
Micrel's SuperSwitcherMIC4680 buck regulator first family products offering unparalleled output power smallest, simplest footprints. MIC4680 industry's first surface mount switching regulator, providing more than output current SO-8 package with only four external components. Devices capable providing MIC4680's high output current have traditionally only been available large, high power packages such TO-220 TO-263, which more than five times size MIC4680! secrets MIC4680 SO-8 package with half thermal resistance regular SO-8. This achieved utilizing concept which MOSFET manufacturers have been using years: having four pins side package connected lead frame sits giving thermal resistance from outside world. This makes MIC4680 only very flexible, more reliable costeffective solution user.
MIC4680 Glance
Simple buck regulator input voltage operating range, abs. max. Over continuous output current SO-8 package with twice normal power handling capabilities Only four external components Replaces larger TO-220 TO-263 solutions 200kHz switching frequency Nearly zero current shutdown, typically Internally compensated with typical small signal bandwidth 20kHz Fixed output voltages 3.3V well adjustable version down 1.25V Full current thermal limit Operation temp -40°C +125°C
34VIN
ON/OFF
68µH 100µF MIC4680 MIC4680 SO-8 SO-8
<5µA Shutdown Current 200KHz
SO-8 with normal (63°C/W) Runs cool More reliable Dissipates excess heat into ground plane
Contents
MIC4680: Worlds' Simplest Surface Mount Switcher MIC5245: Newest Addition µCapFamily MIC2778: Power Supervisor Portables MIC7201: Differential-to-Single-Ended Converter QwikRadioReceivers Update MIC2550: Transceiver Mobile Products MIC39500: Voltage, High Current FPGAs Application: Single-Cell Li-Ion Battery Charger MIC5014: Plug Control Circuit
Micrel Semiconductor
1849 FORTUNE DRIVE JOSE, 95131 U.S.A. HTTP://
World's Best LDO, MIC5245
MIC5245 world-class CMOS latest addition Micrel's family µCap low-dropout regulators. excels above beyond competitors dropout voltage (100mV 100mA), ground current (100µA over full load), noise (30µVrms). MIC5245 also unique push-pull output stage, allowing extremely fast transient response. This output stage allows regulator sink source current, which increases transient response speed significantly over traditional source-only LDOs. lower dropout noise, coupled with fast transient response fast turn-on time make MIC5245 ideal cellular phone technologies.
Features
Stable with capacitor, either ceramic tantalum Output noise: 30µVrms Dropout voltage: 100mV 100mA Quiescent current: 100µA (constant over load) Fast transient response: totem-pole output Fast turn-on time: 50µs (COUT 10µF, CBYP 10nF) Active shutdown clamp: fast turn-off time
Totem Pole Output Fast Transient Response
2.7V
MIC5245
10µF Near zero current
Clever Stuff
Cerami Tantalu Outp Caps
10nF
Noise bypass ultra-low noise
MIC5205 Standard Noise Past Years
MIC5245 Standard
Better Better Noise Noise Performance Performance
10dB! 10dB!
MIC5205-3.0 Phase Noise
MIC5245-3.0 Phase Noise
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Voltage Supervisor Eliminates Battery Headaches
Micrel's MIC2778 voltage supervisor first supervisor optimized tasks like battery detection portable devices. External resistors control high trip points independently, making hysteresis completely adjustable. more chattering, more waiting factory trimmed parts. Unlike most supervisors, MIC2778 separate pin, inputs output pulled above without adverse effects such latch-up excessive current draw. built-in 140ms delay generator automatically de-glitches output, which wire-OR'd with other signals.
Battery Detected; System Shuts Down (But Long!)
VBATT
Features
Optimized battery voltage monitoring Separate trip points adjustable hysteresis 140ms (min.) delay generator de-glitches output Separate input Active-low, open-drain output Inputs output pulled above Ultra-low supply current, 1.0µA (typ.) Micrel's IttyBittySOT23-5 package
Adequate Hysteresis Prevents Chatter Battery Voltage Battery Detected; Recovers System Shuts Down
Inadequate Hysteresis Causes Chatter Battery Voltage Recovers (Drives Users Crazy!)
VBATT
VHIGH
VLOW
VHYST
VLOW
BAT_LOW
Competition
TIME
Micrel
BAT_LOW
TIME
Others Chatter Battery
Micrel Doesn't Chatter
Differential Single-Ended Conversion Made Simple
MIC7201 combines high performance rail-to-rail with precision on-board resistors, creating differential-to-single-ended converter Micrel's IttyBittySOT23-5 package. additional external components required, output biased midsupply.
Differential
Single-Ended
Features
100k 100k
IttyBittySOT23-5 packaging external components required
MIC7201
Specs
1MHz gain-bandwidth 2.8V supply voltage 0.5mA supply current
Micrel Semiconductor
1849 FORTUNE DRIVE JOSE, 95131 U.S.A.
QwikRadioReceivers Enable Wireless Applications
Micrel's QwikRadio receivers provide wireless capability previously wired applications addressing drawbacks cost complexity
Input
INPUT
Digita
DATA
SHUTDOWN
MICRF003
Inductors
QwikRadio Easy
past, receiver design quite complex, requiring many external components manual tuning. QwikRadio simplifies receiver design. Most these requirements integrated chip, eliminating need manual tuning. This reduces number external components down just antenna, low-cost ceramic resonator, couple capacitors, power supply.
Trim Pots
"WAKE" function which used enable receiving system upon detection incoming data.
QwikRadio Cost
QwikRadio combines component count with much lower manufacturing cost production trimming) competitive pricing.
Specs QwikRadio Trimming
QwikRadio receivers true single-chip receivers taking RFin producing digital data-out with trim-pots just three external components. Production trimming adds cost introduces quality concerns. Trim-pots drift over time, impacting reliability range. 400MHz 900MHz bands Data rate 20kbps power 2.4mA continuous operation 240µA polled (10% duty cycle)
Target Applications QwikRadio Power
Micrel's all-CMOS integrated design offers significant power savings over bipolar discrete implementations. Power savings further optimized MICRF002 MICRF003, which ideally suited duty-cycling. addition, both feature
Part Number MICRF001 MICRF011 MICRF002 MICRF022 MICRF003 MICRF033
Remote Switching lights, ceiling fans Remote Control set-top boxes Security Systems remote keyless entry, garage door openers Wireless Data utility metering, wireless keyboard mouse, game controllers
Package
Operating Frequency
440MHz 1000MHz
Data Rate
8-pin SOIC 8-pin
14-pin SOIC
14-pin
16-pin SOIC
16-pin
TEL:
4.8kbps 10kbps 10kbps 10kbps 20kbps 20kbps
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1.800.401.9572 FAX: 408.474.0159
MIC39500 Powering Today's Voltage, High Current FPGAs
Features
2.5V guaranteed 500mV dropout 3-pin, 500mV dropout full load temperature efficiency when operating supply Only output capacitor required operation Fast transient response tolerance Fully protected with current limit, thermal shutdown reversed lead insertion lower current output, MIC39300 (3A), MIC39150 (1.5A) MIC39100 (1A).
Only 500mV Drop
3.0V
VOUT 2.5V 47µF
Altera trademark Altera Corporation. Xilinx trademark Xilinx, Inc.
3.3V Voltage
World's Only Transceiver Mobile Products
planning communications your next design, Micrel's MIC2550 saves time money! MIC2550 employs unique dual supply voltage design which allows operate down 2.5V system side, connect directly voltage bus. With MIC2550, operate your embedded controller ASIC down 2.5V without additional voltage translation circuitry special cells, which would normally necessary support 3.3V signalling. addition, MIC2550 takes operating power directly from voltage bus, which decreases power consumed from your system's battery. MIC2550 will draw more than from your battery, enhancing battery life today's mobile products.
2.5V 5.25V
Features
Bidirectional differential-to-single-ended data conversion Integrated 3.3V termination Fully compliant specification Operates down 2.5V Unique dual supply voltage design quiescent current speed (1.5Mbps) high speed (12Mbps) support power suspend mode height TSSOP package
Transceiver supply current direct from USB, system supply, saving power consumption Built-in saves cost space providing 3.3V termination
MIC2550
VBUS VTRM
Embedded Controller ASIC
MIC2550 interface runs from same supply ASIC, making input output signals fully compliant
Micrel Semiconductor
1849 FORTUNE DRIVE JOSE, 95131 U.S.A.
Constant Current Voltage Single-Cell LithiumIon Battery Charger
Jeff Dixon, Senior Applications Engineer
Introduction
Micrel MIC2179 current-mode, 200kHz, synchronous, buck (step-down) regulator. this application, MIC2179 configured provide both constant-current constant-voltage 1-cell lithium battery charger. current sensed high side avoid ground-bounce noise associated problems usually found ground referenced circuits. Voltage sensed using simple voltage controller reduce parts count provide 0.5% voltage tolerance. MIC2179 operates from 4.5V 16.5V input following value-added features: dual-mode (skip-mode, PWM-mode) operation high efficiency 96%), quiescent current (1.0mA mode, 600µA skip mode), internal current limit, thermal shutdown, undervoltage lockout (4.35V), dropout (100% duty cycle) simplified loop compensation (current-mode control).
(see manufacturer's specification). This method replaces majority battery's charge quickly possible until overcharge voltage threshold reached. Float Charge- maintain constant voltage already charged cell. recommended li-ion batteries. Overcharge-is constant-voltage mode function that occurs consecutively after bulk charge. li-ion battery nears full capacity, current decreases, battery's terminal voltage increases until reaches terminal voltage, typically 4.2V. When current becomes enough, less than trickle-charge normally, charging cycle complete. Li-ion cells should float charged. After charge cycle complete, charger should shut down.
Theory Operation
lithium-ion battery charger divided four blocks: constant-current source, constant-voltage source, switching regulator end-of-charge circuit.
Lithium-Ion Charge States
three charge states lithium-ion battery trickle charge, bulk-charge, overcharge. Starting with fully discharged battery, lithium battery charger needs change modes sequentially through these different charge states. Trickle charge-a constant-current mode used bring battery cutoff voltage (VCUTOFF). battery could deep discharge (2.5V 2.7V cell) many reasons such state charge, ambient temperature, shorted cells, high internal leakage. Bulkcharge-occurs while constant-current mode charger delivering maximum allowable current battery
Constant-Current Block
analyze this block, assume constant-voltage block supporting circuitry) inactive. Starting with discharged battery connected charger, circuit acts like constantcurrent source. MIC2179 synchronous buck regulator provides regulated power. constant-current source's feedback loop consists (current-sense resistor), (MIC6211 amp), (VN2222 N-channel MOSFET), internal 1.24V feedback (MIC2179 synchronous buck regulator). First, lithium-ion battery charger starts trickle-charge
6.5V 16.5V 68µF 100k
100k
16,17
1,2, 19,20
68µH MBRS140 1.24V 0.01µF
SS12 68µF 0.5%
VOUT 4.2V/1.2A Single Li-Ion Cell
PWRGD MIC2179 PGND SYNC COMP
100k 4.2k 100k
1.1M
200k
SGND
9-12
BIAS
Shutdown
HIGH SHUTDOWN ENABLE
VN2222
6.8nF
VN2222
MIC6270
Charge Logic Levels IOUT 120mA IOUT 120mA
0.01µF
MIC6211
MIC6211 VN2222 0.01µF 10.2k 0.5%
100k 1N4148
COMP LM3420M5-4.2 4.2V Voltage Controller 0.01µF
Charge Current
HIGH FAST CHARGE TRICKLE CHARGE
Fast Charge Resistor (1.2A) VN2222
1.15k 0.5%
Trickle Charge Resistor (120mA)
TEL:
1.800.401.9572 FAX: 408.474.0159
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mode. trickle mode, output (MIC6211) biasing allowing output MIC2179 source 121mA charging current battery. intelligent system microprocessor senses logic level output places charger into bulk-mode charging state (1.2A). Sequencing from trickle mode bulk mode accomplished applying logic high Q2's gate. bulk-mode, current ramps 1.20A (for 1-cell lithium application) through sense-resistor (100m) creating 120mV drop. Initially, inverting input lower than noninverting input causing output higher, increasing drive This increases current through parallel combination until 1.24V developed across them. MIC2179 feedback senses 1.24V compares internal 1.24V bandgap reference reduces output duty cycle until 120mV maintained across resistor Finally, there 120mV both inputs MIC6211 amp), completing negative feedback loop. Trickle charge bulk charge calculated using:
1.24V Trickle Charge Current 121mA
across battery increasing over time. change current versus voltage function changing internal impedance lithium-ion battery under charge. being used differential amplifier monitor output current sensing drop across sense resistor gain 102.5. gain maintain greater than 1.24V output down IOUT greater than 120mA. compares output against 1.24V bandgap reference non-inverting generated internal bandgap reference MIC2179. bulk-charge mode, output always higher than U4's reference voltage, thus maintaining logic level end-of-charge pin. Once less than 12mV drop across output longer sustain greater than 1.24V output. 1.24V both inputs. Next, IOUT drawn battery reduces even further charging. voltage U4's inverting lower than 1.24V reference producing logic level high output signaling end-of-charge. present industry-standard variable used determine
CELL VOLTAGE
Cell Voltage
Constant-Voltage Source
Once battery's terminal reaches 4.2V (1-cell lithiumion battery overcharge threshold), constant-current source circuit biased off. output voltage charger tries higher than 4.2V, output (open-emitter configuration) biases feedback MIC2179 pulled-up toward 4.2V VOUT rail, reducing duty cycle maintaining output voltage regulation. constant voltage feedback loop consists (LM3420A), (MIC2179), Because overvoltage conditions greatly reduce life span lithium battery, LM3420A chosen voltage feedback loop help maintain terminal voltage 0.5%. this charger design when input supply disconnected, diode reverse biased prevent battery discharge. bifunctional: prevents battery from being discharged when input supply removed; alleviates race condition between LM3420 start-up MIC2179 switching regulator. LM3420 must before output MIC2179 comes
Current
TIME (HRS)
Typical lithium cell voltage charging current
lithium-ion battery end-of-charge current draw about charge (see graph below). end-of-charge current typically about C/10. simple countdown timer circuit (not shown) usually started upon reaching end-of-charge state. Based individual manufacture specification, this completes charge cycle. End-of-charge output current calculated using 1.24V reference:
End-of-Charge Theshold
End-of-Charge Circuit
end-of-charge circuit used signal microprocessor another subsystem when lithium-ion battery pack reached overcharge threshold. Again, this 1-cell lithium-ion application, overcharge threshold 4.2V. Starting with discharged battery charger bulkcharge mode, constant-current decreasing voltage
1.24V
1.24V reference which end-of-charge comparator. Note: This circuit uses 120mA end-of-charge threshold. charge, charging circuit should shut down. recommended float charge li-ion cells long periods time.
Micrel Semiconductor
1849 FORTUNE DRIVE JOSE, 95131 U.S.A.
CHARGE CURRENT
1.24V Bulk Charge Current 1.20A
Hot-Plug Control Circuit Handles Power Rail
MIC5014 high-side driver used perform necessary control protection features hot-plug controller. This simple circuit added circuit board that designed hot-plug into powered backplane. enables supply voltage slowly, preventing current surges that might propagate backward through backplane affect global power supply regulation. Additionally, further protects backplane protecting against short-circuited cards. fully enhancing gate FET. When power applied, and/or Shutdown input released, MIC5014 charges gate through Overcurrent protection provided When excessive output current flows, resulting voltage drop across turns which then switches gate clamp transistor. discharges MOSFET gate, disabling hot-plug controller output. also provides shutdown function. Although MIC5014 rated maximum operating voltage, used this configuration well over 60V. supply voltage clamped (nominal) zener diode, which current limited power dissipated zener must considered. (max) PZENER VIN(min) 10mA 0.44 ILIM
Features
Adjustable output rise time Adjustable current limit High voltage operation Hot-swap compatible Fast reaction short circuits (<10µs)
Circuit Operation
MIC5014 High Side N-Channel MOSFET driver provides supervoltage (output voltage higher than input voltage) suitable
GATE
OUTPUT
MIC5014 MIC5014 SOURCE 330k
2.7k
1N4002
SHUTDOWN
High Voltage "Hot Swap" circuit schematic. When power suddenly applied VIN, output enabled slowly prevent current surges their resulting voltage transients
Contact Micrel Semiconductor
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Micrel Europe Sales Office
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Micrel Semiconductor Asia Ltd.
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Worldwide
http://www.micrel.com
Literature Requests
USA: 1-800-401-9572 Outside U.S.: Contact sales office
TEL:
1.800.401.9572 FAX: 408.474.0159
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