MAX1966ESA-MAX1967EUB Fast Delivery |IC PHOENIX CO.,LIMITED

MAX1967EUB ,PLASTIC ENCAPSULATED DEVICESELECTRICAL CHARACTERISTICS(VIN = VL = VCC = 5V (MAX1967), VIN = 5V (MAX1966), T = -40°C to +85°C (N ..
MAX1967EUB ,PLASTIC ENCAPSULATED DEVICESFeaturesThe MAX1966/MAX1967 are voltage-mode pulse-width- Cost-Optimized Designmodulated (PWM), st ..
MAX1967EUB ,PLASTIC ENCAPSULATED DEVICESapplications.RequiredThey drive low-cost N-MOSFETs for both the high-sideswitch and synchronous rec ..
MAX1967EUB ,PLASTIC ENCAPSULATED DEVICESApplicationsMAX1966ESA -40°C to +85°C 8 SOMAX1967EUB -40°C to +85°C 10 µMAXSet-Top Boxes Telecom Po ..
MAX1967EUB+ ,Low-Cost Voltage-Mode PWM Step-Down ControllersApplicationsMAX1966ESA -40°C to +85°C 8 SOMAX1967EUB -40°C to +85°C 10 µMAXSet-Top Boxes Telecom Po ..
MAX1967EUB+ ,Low-Cost Voltage-Mode PWM Step-Down Controllersapplications.RequiredThey drive low-cost N-MOSFETs for both the high-sideswitch and synchronous rec ..
MAX491EPD ,Low-Power / Slew-Rate-Limited RS-485/RS-422 TransceiversApplicationsMAX481C/D 0°C to +70°C Dice*Industrial-Control Local Area NetworksOrdering Information ..
MAX491EPD+ ,±15kV ESD-Protected, Slew-Rate-Limited, Low-Power, RS-485/RS-422 TransceiversApplications:ate from a single +5V supply.MAX3293/MAX3294/MAX3295: 20Mbps, +3.3V,Drivers are short- ..
MAX491ESD ,Low-Power / Slew-Rate-Limited RS-485/RS-422 TransceiversFeaturesThe MAX481, MAX483, MAX485, MAX487–MAX491, and' In µMAX Package: Smallest 8-Pin SOMAX1487 a ..
MAX491ESD ,Low-Power / Slew-Rate-Limited RS-485/RS-422 TransceiversGeneral Description ________
MAX491ESD+ ,±15kV ESD-Protected, Slew-Rate-Limited, Low-Power, RS-485/RS-422 TransceiversApplicationsMAX481EESA -40°C to +85°C 8 SOIndustrial-Control Local Area Networks MAX483ECPA 0°C to ..
MAX491ESD+T ,±15kV ESD-Protected, Slew-Rate-Limited, Low-Power, RS-485/RS-422 TransceiversApplications:ceivers on the bus. The MAX488E–MAX491E areMAX3483E/MAX3485E/MAX3486E/MAX3488E/designe ..

MAX1966ESA-MAX1967EUB
Low-Cost Voltage-Mode PWM Step-Down Controllers
General Description
The MAX1966/MAX1967 are voltage-mode pulse-width-
modulated (PWM), step-down DC-DC controllers that
are ideal for a variety of cost-sensitive applications.
They drive low-cost N-MOSFETs for both the high-side
switch and synchronous rectifier and require no external
Schottky power diode or current-sense resistor. Short-
circuit and current-limit protection is provided by sens-
ing the drain-to-source voltage on the low-side FET.
Both devices can supply outputs as low as 0.8V and are
well suited for DSP cores and other low-voltage logic.
The MAX1966 has an input range of 2.7V to 5.5V while
the MAX1967 has an input range of 2.7V to 28V. In
ultra-low-cost designs, the MAX1966/MAX1967 can
provide efficiency exceeding 90% and can achieve
95% efficiency with optimized component selection.
The MAX1966/MAX1967 operate at 100kHz and ac-
commodate aluminum electrolytic capacitors and pow-
dered-iron core magnetics in minimum-cost designs.
They also provide excellent performance with high-per-
formance surface-mount components. The MAX1966 is
available in a low-cost 8-pin SO package. The MAX1967
is available in a 10-pin µMAX package.
Applications
FeaturesCost-Optimized DesignNo Schottky Diode or Current-Sense Resistor
Required>95% EfficiencyLow-Cost External ComponentsAll N-Channel FET Design2.7V to 5.5V Input Range (MAX1966)2.7V to 28V Input Range (MAX1967)0.8V Feedback for Low-Voltage Outputs100kHz Switching Frequency Accommodates
Low-Cost ComponentsThermal ShutdownOutput Current-Limit and Short-Circuit Protection
MAX1966/MAX1967
Low-Cost Voltage-Mode PWM
Step-Down Controllers
Pin Configurations
Ordering Informationypical Operating Circuit
19-2286; Rev 1; 9/03
Set-Top Boxes
Graphic Card Supplies
xDSL Modems and
Routers
Cable Modems and
Routers
Telecom Power Supplies
Networking Power
Supplies
Termination Supplies
MAX1966/MAX1967
Low-Cost Voltage-Mode PWM
Step-Down Controllers
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS
(VIN = VL = VCC = 5V (MAX1967), VIN = 5V (MAX1966), TA= -40°C to +85°C (Note 1), unless otherwise noted. Typical values are at = +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.
(All Voltages Referenced to GND, Unless Otherwise Noted)
VIN to GND (MAX1966)............................................-0.3V to +6V
VIN to GND (MAX1967)..........................................-0.3V to +30V
VCC to GND (MAX1967)..........-0.3V, lower of 6V or (VIN+ 0.3V)
FB to GND................................................................-0.3V to +6V
DL, COMP/EN to GND (MAX1966)................-0.3V to VIN+ 0.3V
VL, DL, COMP/EN to GND (MAX1967).........-0.3V to VCC+ 0.3V
BST to LX..................................................................-0.3V to +6V
DH to LX........................................................-0.3V to BST + 0.3V
VL Short to GND (MAX1967)....................................................5s
RMS Input Current (any pin).............................................±50mA
Continuous Power Dissipation (TA= +70°C)
8-Pin SO (derate 5.88mW/°C above +70°C)................471mW
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 (soldering, 10s).................................+300°C
MAX1966/MAX1967
Low-Cost Voltage-Mode PWM
Step-Down Controllers
ELECTRICAL CHARACTERISTICS (continued)
(VIN = VL = VCC = 5V (MAX1967), VIN = 5V (MAX1966), TA= -40°C to +85°C, unless otherwise noted. Typical values are at = +25°C.)
Note 2:Thermal shutdown disables the buck regulator when the die reaches this temperature. Soft-start is reset and COMP/EN is
discharged to zero. In the MAX1967, the VL regulator remains on during thermal shutdown.
MAX1966/MAX1967
Low-Cost Voltage-Mode PWM
Step-Down Controllers
Typical Operating Characteristics
(TA = +25°C, unless otherwise noted.)
MAX1966/MAX1967
Low-Cost Voltage-Mode PWM
Step-Down Controllers
EFFICIENCY vs. LOAD CURRENT (3.3V/5A)
MAX1967
MAX1966 toc10
LOAD CURRENT (A)
EFFICIENCY (%)7098
FREQUENCY vs. INPUT VOLTAGE
MAX1966 toc11
INPUT VOLTAGE (V)
FREQUENCY (kHz)
FREQUENCY vs. TEMPERATURE
MAX1966 toc12
TEMPERATURE (°C)
FREQUENCY (kHz)
2A/div
2A/div
200mV/div
INDUCTOR
CURRENT
IOUT
VOUT
400ms/div
LOAD STEP RESPONSE
MAX1966 toc15
1A/div
1V/div
2V/div
INDUCTOR
CURRENT
VOUT
VIN
2ms/div
START-UP WAVEFORM
MAX1966 toc16
Typical Operating Characteristics (continued)
(TA = +25°C, unless otherwise noted.)
MAX1966/MAX1967
Low-Cost Voltage-Mode PWM
Step-Down Controllers
MAX1966 toc17
IOUTypical Operating Characteristics (continued)
(TA = +25°C, unless otherwise noted.)
Pin Description
MAX1966/MAX1967
Low-Cost Voltage-Mode PWM
Step-Down Controllers
Detailed Description
The MAX1966/MAX1967 are BiCMOS switch-mode
power-supply controllers designed to implement sim-
ple, buck-topology regulators in cost-sensitive applica-
tions. The main power-switching circuit consists of two
N-channel MOSFETs (or a dual MOSFET), an inductor,
and input and output filter capacitors. An all N-channel
synchronous-rectified design provides high efficiency
at reduced cost. Gate drive for the N-channel high-side
switch is provided by a flying capacitor boost circuit
that uses a 0.1µF capacitor connected to BST.
Major circuit blocks of the MAX1966/MAX1967 are
shown in Figures 1 and 2: Control LogicGate Driver OutputsCurrent-Limit ComparatorClock GeneratorRamp GeneratorError AmplifierError ComparatorSoft-Start5V Linear Regulator (MAX1967)800mV ReferenceThermal Shutdown
In the MAX1996, most blocks are powered from VIN. In
the MAX1967, an internal 5V linear regulator steps
down the input voltage to supply both the IC and the
gate drivers. The synchronous-rectified gate driver is
directly powered from 5V VL, while the high-side-switch
gate driver is indirectly powered from VLplus an exter-
nal diode-capacitor boost circuit.
Resistorless Current Limit
The MAX1966/MAX1967 use the RDS(ON)of the low-
side N-channel MOSFET to sense the current. This
eliminates the need for an external sense resistor usual-
ly placed in series with the output. The voltage mea-
sured across the low-side RDS(ON)is compared to a
fixed -305mV reference (Figures 1 and 2).The peak
inductor current limit is given by the equation below:
MOSFET Gate Drivers
The DH and DL drivers are optimized for driving
MOSFETs with low gate charge. An adaptive dead-time
circuit monitors the DL output and prevents the high-
side FET from turning on until the low-side MOSFET is
fully off. There must be a low-resistance, low-inductance
connection from the DL driver to the MOSFET gate for
the adaptive dead-time circuit to work properly.
Otherwise, the sense circuitry in the MAX1966/
MAX1967 detects the MOSFET gate as off while there
is charge left on the gate. Use very short, wide traces
measuring no less than 50mils to 100mils wide if the
MOSFET is 1in away from the MAX1966/MAX1967. The
same type of adaptive dead-time circuit monitors the
DH off edge. The same recommendations apply for the
gate connection of the high-side MOSFET.
The internal pulldown transistor that drives DL low is
robust, with a 1.1Ωtypical on-resistance. This helps
prevent DL from being pulled up due to capacitive cou-
pling from the drain to the gate of the low-side synchro-
nous-rectifier MOSFET during the fast rise time of the
inductor node. The gate drivers are capable of driving
up to 1A. Use MOSFETs with combined total gate
charge of less than 200nC and a maximum VTHof 3.5V.
Internal Soft-Start
The MAX1966/MAX1967 feature an internally set soft-
start function that limits inrush current. It accomplishes
this by ramping the internal reference input to the con-
troller transconductance amplifier from 0 to the 0.8V
reference voltage. The ramp time is 1024 oscillator
cycles that begins when initial power is applied. At the
nominal 100kHz switching rate, the soft-start ramp is
approximately 10ms. The soft-start does not function if
the MAX1966/MAX1967 are shut down by pulling
COMP/EN low.
High-Side Gate-Drive Supply (BST)
Gate-drive voltage for the high-side N-channel switch is
generated by a flying-capacitor boost circuit (Figures 3
and 4). The flying capacitor is connected between BST
and LX.
On startup, the synchronous rectifier (low-side MOS-
FET) forces LX to ground and charges the boost
capacitor to 5V. On the second half-cycle, the
MAX1966/MAX1967 turn on the high-side MOSFET by
closing an internal switch between BST and DH. This
provides the necessary gate-to-source voltage to drive
the high-side FET gate above its source at the input
voltage.
Internal 5V Linear Regulator
(MAX1967)
All MAX1967 functions are internally powered from an
on-chip, low-dropout 5V regulator. The MAX1967 has a
maximum regulator input voltage (VVIN) of 28V. The
VCC pin must be connected to VL through a 10Ωresis-
tor and VL must be bypassed with a 2.2µF capacitor to
GND. For operation at VVIN< 5V, connect VL to VIN
MAX1966/MAX1967
Low-Cost Voltage-Mode PWM
Step-Down Controllers
Figure 3. MAX1966 Typical Application
Figure 4. MAX1967 Typical Application
Figure 1. MAX1966 Functional Diagram
Figure 2. MAX1967 Functional Diagram

Partno	Mfg	Dc	Qty	Available	Descript
MAX1966ESA	MAXIM	N/a	24	avai	Low-Cost Voltage-Mode PWM Step-Down Controllers
MAX1967EUB		N/a	2500	avai	PLASTIC ENCAPSULATED DEVICES
MAX1967EUB	MAXIM ?	N/a	1350	avai	PLASTIC ENCAPSULATED DEVICES
MAX1967EUB	MAX	N/a	8190	avai	PLASTIC ENCAPSULATED DEVICES
MAX1967EUB	MAXIM	N/a	8190	avai	PLASTIC ENCAPSULATED DEVICES