MAX1801EKA+T ,Digital-Camera Step-Up Slave DC-DC ControllerELECTRICAL CHARACTERISTICS(Circuit of Figure 1, V = +3.3V, V = +1.25V, V = +1.25V, T = 0°C to +85°C ..
MAX1801EKA-T , Digital Camera Step-Up Slave DC-DC Controller
MAX1802EHJ ,Digital Camera Step-Down Power SupplyApplicationsPART TEMP. RANGE PIN-PACKAGEDigital Still CamerasMAX1802EHJ -40°C to +85°C 32 TQFPDigit ..
MAX1802EHJ+ ,Digital Camera Step-Down Power SupplyApplicationsPART TEMP. RANGE PIN-PACKAGEDigital Still CamerasMAX1802EHJ -40°C to +85°C 32 TQFPDigit ..
MAX1802EHJ+T ,Digital Camera Step-Down Power SupplyELECTRICAL CHARACTERISTICS(Circuit of Figure 1, V = 6V, V = 3V, PGNDM = PGND = GND, DCON1 = REF, V ..
MAX1805MEE ,Multichannel Remote/Local Temperature SensorsELECTRICAL CHARACTERISTICS(V = +3.3V, STBY = V , configuration byte = X0XXXX00, T = 0°C to +125°C, ..
MAX4659ESA+ ,High-Current, 25Ω, SPDT, CMOS Analog SwitchesFeaturesThe MAX4659/MAX4660 are medium voltage CMOS♦ High Continuous Current Handlinganalog switche ..
MAX4659ESA+ ,High-Current, 25Ω, SPDT, CMOS Analog SwitchesMAX4659/MAX466019-2046; Rev 1; 1/07High-Current, 25ΩΩ , SPDT, CMOSAnalog Switches
MAX4659EUA ,High-Current / 25 / SPDT / CMOS Analog SwitchesApplications* Exposed paddleRelay Replacement Test EquipmentCommunication SystemsPin Configurationx ..
MAX4659EUA ,High-Current / 25 / SPDT / CMOS Analog SwitchesELECTRICAL CHARACTERISTICS—Dual Supplies(V+ = +15V, V- = -15V, V = 2.4V, V = 0.8V, T = T to T , unl ..
MAX4659EUA+ ,High-Current, 25Ω, SPDT, CMOS Analog SwitchesApplicationsPin ConfigurationRelay Replacement Test EquipmentTOP VIEWCommunication SystemsxDSL Mode ..
MAX465CNG ,Two-Channel, Triple/Quad RGB Video Switches and BuffersApplicationsV- 6 19 V-Broadcast-Quality Color-Signal MultiplexingV- 7 18 OUT0RGB MultiplexingIN0B 8 ..
MAX1801EKA+T
Digital-Camera Step-Up Slave DC-DC Controller
General DescriptionThe MAX1801 step-up slave DC-DC controller is used
with either the MAX1800 (step-up) or the MAX1802 (step-
down) master DC-DC converter to provide a complete
power-supply solution for digital still and digital video
cameras. By using the master converter’s reference volt-
age and oscillator, the size and the cost of the slave con-
troller are reduced and all converters are guaranteed to
switch at the same frequency.
The MAX1801 drives an external N-channel MOSFET
and can be used in step-up, single-ended primary
inductance converter (SEPIC), and flyback topologies. If
extra supplies are required for a new design, slave con-
trollers can be added to an existing master circuit with
minimal redesign, saving both cost and time. The
MAX1801 features a built-in soft-start, short-circuit pro-
tection, and an adjustable duty-cycle limit.
The MAX1801 is available in a space-saving 8-pin
SOT23 package. Separate evaluation kits combining the
MAX1800/MAX1801 (MAX1800EVKIT) and MAX1802/
MAX1801 (MAX1802EVKIT) are available to expedite
designs.
________________________Applications
FeaturesProvides Simple Expandability for the MAX1800
and MAX1802 Master ConvertersOperates in Step-Up, SEPIC, and Flyback
Topologies100kHz to 1MHz Adjustable Operating FrequencyDuty-Cycle Limit Adjustable from 40% to 90%Soft-Start Short-Circuit Protection0.01µA Supply Current in Shutdown ModeTiny 8-Pin SOT23 Package
MAX1801
Digital Camera Step-Up Slave
DC-DC Controllerypical Operating Circuit19-1741 Rev 0; 10/00
Ordering Information
Pin Configuration appears at end of data sheet.Digital Still Cameras
Digital Video Cameras
Portable DVD Players
Internet Access Tablets
PDAs
Hand-Held Devices
MAX1801
Digital Camera Step-Up Slave
DC-DC Controller
ABSOLUTE MAXIMUM RATINGSStresses 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.
IN, DCON, REF, OSC, FB to GND.........................-0.3V to +6.0V
DL, COMP to GND.......................................-0.3V to (VIN+ 0.3V)
Continuous Power Dissipation (TA= +70°C)
8-Pin SOT23 (derate 6mW/°C above+70°C)................480mW
Operating Temperature Range...........................-40°C to +85°C
Junction Temperature......................................................+150°C
Storage Temperature Range.............................-65°C to +150°C
Lead Temperature (soldering, 10s).................................+300°C
ELECTRICAL CHARACTERISTICS(Circuit of Figure 1, VIN= +3.3V, VDCON= +1.25V, VREF= +1.25V, TA
= 0°C to +85°C, unless otherwise noted. Typical values are at = +25°C.) (Note 1)
MAX1801
Digital Camera Step-Up Slave
DC-DC Controller
ELECTRICAL CHARACTERISTICS
ELECTRICAL CHARACTERISTICS (continued)(Circuit of Figure 1, VIN= +3.3V, VDCON= +1.25V, VREF= +1.25V, TA
= 0°C to +85°C, unless otherwise noted. Typical values are at
MAX1801
Digital Camera Step-Up Slave
DC-DC Controller
ELECTRICAL CHARACTERISTICS(continued)
(Circuit of Figure 1, VIN= +3.3V, VDCON= +1.25V, VREF= +1.25V, TA= -40°C to +85°C, unless otherwise noted.) (Note 1)
Typical Operating Characteristics
(Circuit of Figure 1, TA = +25°C, unless otherwise noted.)
Note 2:Oscillator signal is generated by the MAX1800 or MAX1802.
MAX1801
Digital Camera Step-Up Slave
DC-DC Controller
MAXIMUM DUTY CYCLE vs. VDCONMAX1801 toc04
VDCON (V)
MAXIMUM DUTY CYCLE (%)
DEFAULT MAXIMUM DUTY CYCLE
vs. FREQUENCY
MAX1801 toc05
FREQUENCY (kHz)
DEFAULT MAXIMUM DUTY CYCLE (%)
SLEEP-MODE CURRENT
vs. INPUT VOLTAGE
MAX1801toc06
INPUT VOLTAGE (V)
SLEEP-MODE CURRENT (
SHUTDOWN CURRENT
vs. REFERENCE VOLTAGE
MAX1801 toc07
REFERENCE VOLTAGE (V)
SHUTDOWN CURRENT (
REFERENCE INPUT CURRENT
vs. TEMPERATURE
MAX1801 toc08
TEMPERATURE (°C)
REFERENCE CURRENT (10010001010,000
FB TO COMP SMALL-SIGNAL OPEN-LOOP
FREQUENCY RESPONSEMAX1801 toc09
FREQUENCY (kHz)
SMALL-SIGNAL RESPONSE (dB)10
Typical Operating Characteristics (continued)(Circuit of Figure 1, TA = +25°C, unless otherwise noted.)
MAX1801
Digital Camera Step-Up Slave
DC-DC Controller
STARTUP RESPONSEMAX1801 toc10
VDCON
5V/div
VOUT
2V/div
IIN
0.5A/div
1ms/div
LOAD TRANSIENT RESPONSEMAX1801 toc11
VOUT
100mV/div
(AC-COUPLED)
400µs/div
ILOAD
0.2A/div
100mA
500mA
Typical Operating Characteristics (continued)(Circuit of Figure 1, TA = +25°C, unless otherwise noted.)
MAX1801
Digital Camera Step-Up Slave
DC-DC Controller
Detailed Description
Master-Slave ConfigurationThe MAX1801 is a step-up slave DC-DC controller that
obtains its input power, voltage reference, and oscilla-
tor signal directly from a MAX1800 or MAX1802 master
DC-DC converter (Figure 1). The master-slave configu-
ration reduces system cost by eliminating redundant
circuitry and controls the harmonic content of noise by
synchronizing converter switching.
Step-Up DC-DC ControllerThe MAX1801 controller operates in a low-noise fixed-
frequency PWM mode, with output power limited by the
external components. The controller regulates the out-
put voltage by modulating the pulse width of the drive
signal for an external N-channel MOSFET switch. The
user-adjusted switching frequency is constant (100kHz
to 1MHz) and set by the master converter.
Figure 2 shows a block diagram of the MAX1801 PWM
controller. A sawtooth oscillator signal from the master
converter (at OSC) governs the internal timing. At the
beginning of each cycle, DL goes high to turn on the
external MOSFET switch. The MOSFET switch turns off
when the internally level-shifted sawtooth waveform
voltage rises above the voltage at COMP or when the
maximum duty cycle is exceeded. The switch remains
off until the beginning of the next cycle. An internal
transconductance amplifier establishes an integrated
error voltage at COMP, increasing the loop gain for
improved regulation accuracy and compensation con-
trol.
ReferenceThe MAX1801 requires a 1.25V reference voltage that
is obtained from the MAX1800 or the MAX1802. REF
typically sinks 0.5µA in shutdown mode, 3µA in active
mode, and up to 30µA during startup. If multiple
MAX1801 controllers are turned on simultaneously,
ensure that the master voltage reference can provide
sufficient current, or buffer the reference with an appro-
priate unity-gain amplifier.
MAX1801
Digital Camera Step-Up Slave
DC-DC Controller
OscillatorThe MAX1801 requires a 0 to 1.25V sawtooth oscillator
signal that is obtained from the MAX1800 or the
MAX1802 (at OSC). The 100kHz to 1MHz oscillator sig-
nal sets the converter switching frequency, and it is
used to control pulse-width modulation and maximum
duty cycle.
Maximum Duty CycleThe MAX1801 uses the master-generated oscillator sig-
nal at OSC, the voltage at DCON, and an internal com-
parator to limit its maximum switching duty cycle (see
Setting the Maximum Duty Cycle). Limiting the duty
cycle can prevent saturation in some magnetic compo-
nents. A low maximum duty cycle can also force the
converter to operate in discontinuous current mode,
simplifying design stability at the cost of a slight reduc-
tion in efficiency.
Soft-StartThe MAX1801 features a soft-start function that limits
inrush current and prevents excessive battery loading
at startup by ramping the output voltage to the regula-
tion voltage. This is achieved by increasing the internal
reference to the transconductance amplifier from 0 to
the 1.25V reference voltage over 1024 oscillator cycles
when initial power is applied or when the part is taken
out of shutdown or sleep mode.
