IC Phoenix
 
Home ›  MM29 > MAX1698AEUB+-MAX1698EUB+-MAX1698EUB+T-MAX1698EUB-T,High-Efficiency Step-Up Current Regulator for LEDs
MAX1698AEUB+-MAX1698EUB+-MAX1698EUB+T-MAX1698EUB-T Fast Delivery,Good Price
Part Number:
If you need More Quantity or Better Price,Welcom Any inquiry.
We available via phone +865332716050 Email
Partno Mfg Dc Qty AvailableDescript
MAX1698AEUB+ |MAX1698AEUBMAXIMN/a1600avaiHigh-Efficiency Step-Up Current Regulator for LEDs
MAX1698EUB+ |MAX1698EUBMAXIMN/a5750avaiHigh-Efficiency Step-Up Current Regulator for LEDs
MAX1698EUB+TN/AN/a2500avaiHigh-Efficiency Step-Up Current Regulator for LEDs
MAX1698EUB-T |MAX1698EUBTMAXIMN/a19avaiHigh-Efficiency Step-Up Current Regulator for LEDs


MAX1698EUB+ ,High-Efficiency Step-Up Current Regulator for LEDsFeaturesThe MAX1698 and MAX1698A are efficient drivers for♦ Over 90% Efficiencywhite or color LEDs. ..
MAX1698EUB+T ,High-Efficiency Step-Up Current Regulator for LEDsapplications of 5W or more. Both devices aresupplied in a space-saving 10-pin µMAX package thatTOP ..
MAX1698EUB-T ,High-Efficiency Step-Up Current Regulator for LEDsApplicationsMAX1698AADJ 4 7 GNDBacklight for LCD PanelsGND 5 6 FBNotebook PCsHandy TerminalsµMAXPDA ..
MAX170 ,Serial Output, 5.6µs, 12-Bit ADC with ReferenceFeatures 12-Bit Resolution and Linearity 5.tips Fast Conversion Time Serial Output Self ..
MAX17000AETG+ ,Complete DDR2 and DDR3 Memory Power-Management SolutionApplicationsSHDN 24 7 PGND2Notebook Computers1 2 3 45 6DDR, DDR2, and DDR3 Memory SuppliesSSTL Memo ..
MAX17000AETG+T ,Complete DDR2 and DDR3 Memory Power-Management Solutionapplications) with ease and provides 100ns responseOutput Voltages-Preset VDDQ/2 or REFINto load tr ..
MAX4507EAP+ ,Fault-Protected, High-Voltage Signal-Line ProtectorsApplications MAX4506C/D 0°C to +70°C Dice*MAX4506ESA -40°C to +85°C 8 SOProcess-Control Systems MAX ..
MAX4507EAP+ ,Fault-Protected, High-Voltage Signal-Line ProtectorsELECTRICAL CHARACTERISTICS —Dual Supplies (continued)(V+ = +15V, V- = -15V, T = T to T , unless oth ..
MAX4507EAP+T ,Fault-Protected, High-Voltage Signal-Line ProtectorsApplications MAX4506C/D 0°C to +70°C Dice*MAX4506ESA -40°C to +85°C 8 SOProcess-Control Systems MAX ..
MAX4508CSE ,Fault-Protected, High-Voltage Single 8-to-1/Dual 4-to-1 MultiplexersApplicationsOrdering InformationData-Acquisition Systems PART TEMP. RANGE PIN-PACKAGEIndustrial and ..
MAX4508CSE+ ,Fault-Protected, High-Voltage Single 8-to-1/Dual 4-to-1 Multiplexers with Output ClampsMAX4508/MAX450919-1414; Rev 5; 10/07Fault-Protected, High-Voltage Single 8-to-1/Dual 4-to-1 Multipl ..
MAX4508EPE ,Fault-Protected, High-Voltage Single 8-to-1/Dual 4-to-1 MultiplexersFeaturesThe MAX4508/MAX4509 are 8-to-1 and dual 4-to-1 fault- ' ±40V Fault Protection with Power Of ..


MAX1698AEUB+-MAX1698EUB+-MAX1698EUB+T-MAX1698EUB-T
High-Efficiency Step-Up Current Regulator for LEDs
General Description
The MAX1698 and MAX1698A are efficient drivers for
white or color LEDs. They are ideal for large LED backlit
displays in PDAs and laptop computers. Numerous
benefits include greater simplicity, lower cost, higher
efficiency, longer bulb life, and greater reliability when
compared to fluorescent (CCFL) and electrolumines-
cent (EL) lamps.
The MAX1698/MAX1698A are switch-mode boost con-
trollers in which LED current, rather than output voltage,
is regulated The devices drive series-connected LEDs
with a controlled current that is measured with a typical-
ly 15Ωsense resistor, not an expensive fractional-ohm
value. LED current control and dimming are accom-
plished with an adjust input (ADJ). For larger light out-
put, multiple LED banks can be connected in parallel
with up to 5W total output power.
The MAX1698A has a higher, and more accurately
specified, CS current limit than the MAX1698 for higher-
power applications of 5W or more. Both devices are
supplied in a space-saving 10-pin µMAX package that
occupies half the space of an 8-pin SO. An evaluation
kit (MAX1698EVKIT) is available to speed designs.
Applications

Battery-Powered Backlight Applications
Backlight for LCD Panels
Notebook PCs
Handy Terminals
PDAs
Features
Over 90% EfficiencyLossless, Adjustable LED BrightnessSpace-Saving 10-Pin μMAX PackageSimpler, Lower Cost, More Reliable Compared
to CCFL or EL Backlights
Up to 5W Output Power
MAX1698/MAX1698A
High-Efficiency Step-Up
Current Regulator for LEDs

EXT
PGND
GNDADJ
REF
VCC
MAX1698
MAX1698A
µMAX
TOP VIEWGND
SHDN
VCC
VOUT
COUT
SHDN
GND
ADJ
REFON
OFF
PGND
EXT
VCC
VBATT
ILED
RFBRN
MAX1698
MAX1698A
Typical Operating Circuit

19-1621; Rev 2; 2/07
Pin Configuration
Ordering Information
PARTT EM P RA N G EPIN -
PA C K A G E
PKG
CODE
MAX1698EUB
-40°C to +85°C10µMAXU10-2
MAX1698AEUB
-40°C to +85°C10µMAXU10-2
MAX1698/MAX1698A
High-Efficiency Step-Up
Current Regulator for LEDs
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS

(VCC= +3.3V, TA= 0°C to +85°C, unless otherwise noted. Typical values are at TA= +25°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.
VCC, SHDNto GND..................................................-0.3V to +6V
EXT, FB, CS, ADJ, REF to GND..................-0.3V to (VCC+ 0.3V)
GND to PGND.....................................................................±0.3V
Continuous Power Dissipation (TA= +70°C)
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 +150°C
Lead Temperature Range (soldering, 10s)......................+300°C
FB = GND, ADJ = REF, CS = GND
FB = GND, ADJ = REF
Rising edge
FB = GND
VFB= 0.3V
ADJ = REF
VADJ= 100mV
CONDITIONS
305070ADJ Start Threshold101520tON(MAX)Maximum On Time0.81.01.2tOFF(MIN)Minimum Off Time
ARMS0.8ICSCS Input Current0.81.52.5CS Trip Current2.252.42.55Undervoltage Lockout260500ICC2.75.5VCCSupply Voltage
Quiescent Supply Current80Undervoltage Hysteresis
285300315mV182430VFBFB Regulation Voltage
UNITSMINTYPMAXSYMBOLPARAMETER

VFB= 300mVnA-1515IFBFB Input Bias Current0.03REFVADJADJ Input Range
ADJ Input Bias CurrentIADJADJ = REF-5050nA
Shutdown Supply CurrentSHDN= GND0.011µA
REF Output VoltageVREFIREF= 01.201.251.30V
REF Load Regulation∆VREFIREF= 0 to 150µA-2-25mV
REF Short-Circuit CurrentREF = GND0.451mA
REF Power-Supply Rejection
RatioPSRRVCC= 2.7V to 5.5V+0.3+2mV/V
EXT Driver Sink/Source CurrentVCC= 5V, EXT = 2V0.2A
EXT Driver On-ResistanceVCC= 5V8Ω
SHDNInput High VoltageVIHVCC= 2.7V to 5.5V2V
SHDNInput Low VoltageVILVCC= 2.7V to 5.5V0.8V
SHDNInput Bias CurrentISHDNVCC= 2.7V to 5.5V-11µA
MAX1698
MAX1698A
MAX1698/MAX1698A
High-Efficiency Step-Up
Current Regulator for LEDs
ELECTRICAL CHARACTERISTICS

(VCC= +3.3V, TA= -40°C to +85°C, unless otherwise noted.) (Note 1)
CONDITIONS
VCCSupply Voltage2.75.5
UNITSMINMAXSYMBOLPARAMETER

FB = GND2.03.0
Minimum Off TimetOFF(MIN)FB = GND, ADJ = REF0.61.4µs
Maximum On TimetON(MAX)FB = GND, ADJ = REF, CS = GND921µs
ADJ Start Threshold2575mV
FB Input Bias CurrentIFBVFB= 300mV-2020nA
ADJ Input Bias CurrentIADJADJ = REF-5050nA
Shutdown Supply CurrentSHDN= GND1µA
REF Output VoltageVREFIREF= 01.171.33V
REF Load Regulation∆VREFIREF= 0 to 150µA-30mV
REF Short-Circuit CurrentREF = GND1mA
REF Power-Supply Rejection
RatioPSRRVCC= 2.7V to 5.5V+2mV/V
EXT On-ResistanceVCC= 5V8Ω
SHDNInput High VoltageVIHVCC= 2.7V to 5.5V2V
SHDNInput Low VoltageVILVCC= 2.7V to 5.5V0.8V
SHDNInput Bias CurrentISHDNVCC= 2.7V to 5.5V-11µA
Note 1:
Specifications to -40°C are guaranteed by design, not production tested.
Rising edgeVUndervoltage Lockout2.202.65
VADJ= 100mV
ADJ = REFmV1335VFBFB Regulation Voltage280320
VFB= 0.3VµAICCQuiescent Supply Current500
CS Trip Current0.83.0AMAX1698A
MAX1698
MAX1698/MAX1698A
High-Efficiency Step-Up
Current Regulator for LEDs
5231678910
MXA1698-01
VBATT, VCC (V)
OUTPUT CURRENT (mA)
OUTPUT CURRENT vs. VBATT AND VCC

1 CHAIN OF 4 LEDs
vs. VCC
vs. VBATT
NORMALIZED OUTPUT CURRENT
vs. ADJ VOLTAGE
MXA1698-02
ADJ VOLTAGE (V)
NORMALIZED OUTPUT CURRENT
MXA1698-03
INPUT VOLTAGE (V)
OUTPUT CURRENT (mA)
OUTPUT CURRENT
vs. INPUT VOLTAGE

1 CHAIN OF 4 LEDs
IBATT
IOUT
4 CHAINS OF 4 LEDs
BATTERY CURRENT
vs. BATTERY VOLTAGE
MXA1698-04
VBATT (V)
IOUT,
IBATT
(mA)
EXT RISE/FALL TIME vs. CEXT
MXA1698-05
CEXT (pF)
RISE/FALL TIME (ns)
FALL TIME
RISE TIME
EFFICIENCY vs. BATTERY VOLTAGE
MXA1698-06
BATTERY VOLTAGE (V)
EFFICIENCY (%)
IOUT = 80mA
4 CHAINS OF 4 LEDs
MXA1698-07
EFFICIENCY (%)
EFFICIENCY vs. OUTPUT CURRENT

VBATT = 5V
4 CHAINS OF 4 LEDs
MXA1698-08
IOUT
50mA/div
5ms/div
SHUTDOWN/SOFT-START TIMING

SHDN
5V/div
IBATT
100mA/div
3.3V
4 CHAINS OF 4 LEDsIOUT SET TO 80mA,
MXA1698-09
LED AND INDUCTOR CURRENT
WAVEFORMS

INDUCTOR
CURRENT
500mA/div
LED
CURRENT
50mA/div
1µs/div
Typical Operating Characteristics

(Circuit of Figure 2, VCC= VBATT = 3.3V,VADJ= VREF, TA= +25°C, unless otherwise noted.)
MAX1698/MAX1698A
High-Efficiency Step-Up
Current Regulator for LEDs
NAMEFUNCTION
VCCIC Supply Voltage Input. Power for internal circuitry. Input range is 2.7V to 5.5V.SHDN
Active-Low Shutdown Input. In shutdown, the MOSFET turns off, but a current path still exists between the
input and output. The minimum forward voltage of the LED array must exceed the maximum VBATTto ensure
that the LEDs are off in shutdown.
PIN
REF1.25V Reference Output. Capable of sourcing 150µA for external loads. This pin is internally compensated.
Do not connect any bypass capacitors at REF.ADJAdjust Input. Allows dynamic adjustment of the output current. FB regulates to 300mV when ADJ = REF.FBFeedback Input. Connect to the external LED current-sense feedback resistor.PGNDPower GroundCSFET Current-Sense Input
5, 7GNDGroundEXTGate Driver Output
Pin Description

UNDERVOLTAGE
LOCKOUT/
SHUTDOWN
TRIG
TRIG
PGND
EXT
REFGND
ADJ
SHDN
VCC
VCC
MAX tON
MIN tOFF
MAX1698
SOFT-START1.25V
REFERENCE
Figure 1. Functional Diagram
MAX1698/MAX1698A
High-Efficiency Step-Up
Current Regulator for LEDs
Detailed Description

The MAX1698/MAX1698As' high efficiency and small
size make them ideally suited to drive LEDs. They oper-
ate as a boost DC-DC converter that controls output
current rather than voltage. Losses are minimized by a
low, 300mV current-sense threshold. In the standard
configuration, a feedback resistor, RFB, sets the current
through the primary chain of LEDs. Additional chains of
matching LEDs can be added with an equivalent resis-
tor. In matched LED arrays, the secondary chain cur-
rents closely track the primary chain. An optional zener
diode, D2, prevents overvoltage in the event that one of
the LEDs in the primary chain becomes an open circuit.
The LED brightness can be adjusted dynamically by a
voltage input at ADJ.
Shutdown

In shutdown, the supply current is reduced below 1µA.
EXT goes low in shutdown, shutting off the external N-
channel FET. This leaves a current path between the
input and the LEDs through the boost inductor and
catch diode. The minimum forward voltage of the LED
array must exceed the maximum VBATT to ensure that
the LEDs remain off in shutdown. Typical shutdown tim-
ing characteristics are shown in the Typical Operating
Characteristics.
Soft-Start

The MAX1698/MAX1698A include a soft-start function
that eliminates input current surges at turn-on. They do
this by extending the external FET driver (EXT) mini-
mum off-time during start-up. During the first 512
switching cycles, the minimum off-time is 5µs. It is then
allowed to drop to 2µs for the next 1500 switching
cycles. After that time, the minimum off-time falls to the
1µs value used during normal operation. (See
Shutdown/Soft-Start Timing in the Typical Operating
Characteristicssection.)
Design Procedure
Setting the Maximum LED Current

Resistor RFBsets the maximum current in the primary
chain of LEDs:
where ILEDMAXis the maximum LED current.
Adjusting LED Current

RFBsets the maximum LED current. This current can
be reduced proportional to the voltage at the ADJ pin
(see Normalized Output Current vs. ADJ Voltage in the
Typical Operating Characteristicssection). Figure 3mVFBLEDMAX =300
VCC
SHDN
PGNDGND
RFB
OPTIONAL
LEDs
MBR0540
ADJ
REF
EXT
MAX1698
MAX1698A
VCC = 3.3V
10µF
VBATT = 3.3V
10µH
1µF
15Ω15Ω15Ω15Ω
1µF
Figure 2. Typical Operating Circuit
ic,good price


TEL:86-533-2716050      FAX:86-533-2716790
   

©2020 IC PHOENIX CO.,LIMITED