MAX1653ESE ,High-Efficiency / PWM / Step-Down DC-DC Controllers in 16-Pin QSOPapplications.All devices operate with a selectable 150kHz/300kHzswitching frequency, which can also ..
MAX1653ESE ,High-Efficiency / PWM / Step-Down DC-DC Controllers in 16-Pin QSOPELECTRICAL CHARACTERISTICS(V+ = +15V, GND = PGND = 0V, SYNC = REF, I = I = 0A, T = 0°C to +85°C, u ..
MAX1653ESE ,High-Efficiency / PWM / Step-Down DC-DC Controllers in 16-Pin QSOPapplications.All devices operate with a selectable 150kHz/300kHzswitching frequency, which can also ..
MAX1653ESE ,High-Efficiency / PWM / Step-Down DC-DC Controllers in 16-Pin QSOPGeneral Description ________
MAX1653ESE+ ,High-Efficiency, PWM, Step-Down DC-DC Controllers in 16-Pin QSOPGeneral Description ________
MAX1653ESE+ ,High-Efficiency, PWM, Step-Down DC-DC Controllers in 16-Pin QSOPELECTRICAL CHARACTERISTICS(V+ = +15V, GND = PGND = 0V, SYNC = REF, I = I = 0A, T = 0°C to +85°C, u ..
MAX4411EBE-T ,80mW, Fixed-Gain, DirectDrive, Stereo Headphone Amplifier with ShutdownFeaturesThe MAX4411 fixed-gain, stereo headphone amplifier is ♦ No Bulky DC-Blocking Capacitors Req ..
MAX4411ETP ,80mW, Fixed-Gain, DirectDrive, Stereo Headphone Amplifier with ShutdownMAX441119-2618; Rev 2; 9/0680mW, Fixed-Gain, DirectDrive, StereoHeadphone Amplifier with Shutdown
MAX4411ETP ,80mW, Fixed-Gain, DirectDrive, Stereo Headphone Amplifier with Shutdownapplications. ♦ Short-Circuit and Thermal-Overload ProtectionThe MAX4411 operates from a single 1.8 ..
MAX4411ETP+ ,80mW, Fixed-Gain, DirectDrive, Stereo Headphone Amplifier with ShutdownELECTRICAL CHARACTERISTICS(PV = SV = 3V, PGND = SGND = 0V, SHDNL = SHDNR = SV , C1 = C2 = 2.2µF, C ..
MAX4411ETP+T ,80mW, Fixed-Gain, DirectDrive, Stereo Headphone Amplifier with ShutdownFeaturesThe MAX4411 fixed-gain, stereo headphone amplifier is ♦ No Bulky DC-Blocking Capacitors Req ..
MAX4411ETP+T ,80mW, Fixed-Gain, DirectDrive, Stereo Headphone Amplifier with ShutdownApplicationsMAX4411EBE-T -40°C to +85°C 16 UCSP-16 -1.5Notebook PCs MP3 PlayersMAX4411EBE+T -40°C t ..
MAX1653EEE-MAX1653ESE-MAX1654EEE-MAX1655EEE-MAX1655ESE
High-Efficiency / PWM / Step-Down DC-DC Controllers in 16-Pin QSOP
General DescriptionThe MAX1652–MAX1655 are high-efficiency, pulse-
width-modulated (PWM), step-down DC-DC controllers
in small QSOP packages. The MAX1653/MAX1655 also
come in 16-pin narrow SO packages that are pin-
compatible upgrades to the popular MAX797. Improve-
ments include higher duty-cycle operation for better
dropout, lower quiescent supply currents for better
light-load efficiency, and an output voltage down to 1V
(MAX1655).
The MAX1652–MAX1655 achieve up to 96% efficiency
and deliver up to 10A using a unique Idle Mode™ syn-
chronous-rectified PWM control scheme. These devices
automatically switch between PWM operation at heavy
loads and pulse-frequency-modulated (PFM) operation
at light loads to optimize efficiency over the entire out-
put current range. The MAX1653/MAX1655 also feature
logic-controlled, forced PWM operation for noise-sensi-
tive applications.
All devices operate with a selectable 150kHz/300kHz
switching frequency, which can also be synchronized
to an external clock signal. Both external power switch-
es are inexpensive N-channel MOSFETs, which provide
low resistance while saving space and reducing cost.
The MAX1652 and MAX1654 have an additional feed-
back pin that permits regulation of a low-cost second
output tapped from a transformer winding. The
MAX1652 provides an additional positive output. The
MAX1654 provides an additional negative output.
The MAX1652–MAX1655 have a 4.5V to 30V input volt-
age range. The MAX1652/MAX1653/MAX1654’s output
range is 2.5V to 5.5V while the MAX1655’s output range
extends down to 1V. An evaluation kit (MAX1653EVKIT)
is available to speed designs.
ApplicationsNotebook Computers
PDAs
Cellular Phones
Hand-Held Computers
Handy-Terminals
Mobile Communicators
Distributed Power
____________________________Features96% EfficiencySmall, 16-Pin QSOP Package
(half the size of a 16-pin narrow SO)Pin-Compatible with MAX797 (MAX1653/MAX1655)Output Voltage Down to 1V (MAX1655)4.5V to 30V Input Range99% Duty Cycle for Lower Dropout170µA Quiescent Supply Current3µA Logic-Controlled ShutdownDual, N-Channel, Synchronous-Rectified ControlFixed 150kHz/300kHz PWM Switching,
or Synchronized from 190kHz to 340kHzProgrammable Soft StartLow-Cost Secondary Outputs (MAX1652/MAX1654)
MAX1652–MAX1655
High-Efficiency, PWM, Step-Down
DC-DC Controllers in 16-Pin QSOP
Pin Configurations appear at end of data sheet.Idle Mode is a trademark of Maxim Integrated Products.
MAX1652–MAX1655
High-Efficiency, PWM, Step-Down
DC-DC Controllers in 16-Pin QSOP
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS(V+ = +15V, GND = PGND = 0V, SYNC = REF, IVL= IREF= 0A, TA
= 0°C to +85°C, unless otherwise noted.)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.
V+ to GND..............................................................-0.3V to +36V
GND to PGND.......................................................-0.3V to +0.3V
VL to GND................................................................-0.3V to +6V
BST to GND............................................................-0.3V to +36V
DH to LX.....................................................-0.3V to (BST + 0.3V)
LX to BST..................................................................-6V to +0.3V
SHDNto GND...............................................-0.3V to (V+ + 0.3V)
SYNC, SS, REF, SECFB, SKIP,FB to GND...-0.3V to (VL + 0.3V)
DL to PGND..................................................-0.3V to (VL + 0.3V)
CSH, CSL to GND....................................................-0.3V to +6V
VL Short Circuit to GND..............................................Momentary
REF Short Circuit to GND...........................................Continuous
VL Output Current...............................................+50mA to -1mA
REF Output Current...............................................+5mA to -1mA
Continuous Power Dissipation (TA= +70°C)
SO (derate 8.70mW/°C above +70°C) .......................696mW
QSOP (derate 8.3mW/°C above +70°C) ....................667mW
Operating Temperature Range
MAX165_E_E ..................................................-40°C to +85°C
Storage Temperature Range.............................-65°C to +160°C
Lead Temperature (soldering, 10sec).............................+300°C
MAX1652–MAX1655
High-Efficiency, PWM, Step-Down
DC-DC Controllers in 16-Pin QSOP
Note 1:Since the reference uses VL as its supply, V+ line-regulation error is insignificant.
Note 2:At very low input voltages, quiescent supply current may increase due to excessive PNP base current in the VL linear
regulator. This occurs if V+ falls below the preset VL regulation point (5V nominal).
ELECTRICAL CHARACTERISTICS (continued)(V+ = +15V, GND = PGND = 0V, SYNC = REF, IVL= IREF= 0A, TA
= 0°C to +85°C,unless otherwise noted.)
MAX1652–MAX1655
High-Efficiency, PWM, Step-Down
DC-DC Controllers in 16-Pin QSOP
ELECTRICAL CHARACTERISTICS (continued)(V+ = +15V, GND = PGND = 0V, SYNC = REF, IVL= IREF= 0A, TA
= -40°C to +85°C,unless otherwise noted.) (Note 3)
Note 3:Specifications from 0°C to -40°C are guaranteed by design, not production tested.
MAX1652–MAX1655
High-Efficiency, PWM, Step-Down
DC-DC Controllers in 16-Pin QSOP
Typical Operating Circuits
__________________________________________Typical Operating Characteristics(Circuit of Figure 1, SKIP= GND, TA = +25°C, unless otherwise noted.)
MAX1652–MAX1655
High-Efficiency, PWM, Step-Down
DC-DC Controllers in 16-Pin QSOP
Typical Operating Circuits (continued)
MAX1652–MAX1655
High-Efficiency, PWM, Step-Down
DC-DC Controllers in 16-Pin QSOP
____________________________________Typical Operating Characteristics (continued)(Circuit of Figure 1, SKIP= GND, TA = +25°C, unless otherwise noted.)
MAX1652–MAX1655
High-Efficiency, PWM, Step-Down
DC-DC Controllers in 16-Pin QSOP
Typical Operating Characteristics (continued)(Circuit of Figure 1, SKIP= GND, TA = +25°C, unless otherwise noted.)
MAX1652–MAX1655
High-Efficiency, PWM, Step-Down
DC-DC Controllers in 16-Pin QSOP
Pin DescriptionDual Mode is a trademark of Maxim Integrated Products.
MAX1652–MAX1655
High-Efficiency, PWM, Step-Down
DC-DC Controllers in 16-Pin QSOP
Standard Application CircuitsIt’s easy to adapt the basic MAX1653 single-output 3.3V
buck converter (Figure 1) to meet a wide range of appli-
cations with inputs up to 30V (limited by choice of exter-
nal MOSFET). Simply substitute the appropriate
components from Table 1 (candidate suppliers are pro-
vided in Table 2). These circuits represent a good set of
trade-offs among cost, size, and efficiency while staying
within the worst-case specification limits for stress-relat-
ed parameters such as capacitor ripple current.
Don’t change the frequency of these circuits without
first recalculating component values (particularly induc-
tance value at maximum battery voltage).
For a discussion of dual-output circuits using the
MAX1652 and MAX1654, see Figure 9 and the
Secondary Feedback-Regulation Loopsection.
Detailed DescriptionThe MAX1652 family are BiCMOS, switch-mode power-
supply controllers designed primarily for buck-topology
regulators in battery-powered applications where high
efficiency and low quiescent supply current are critical.
The parts also work well in other topologies such as
boost, inverting, and Cuk due to the flexibility of their
floating high-speed gate driver. Light-load efficiency is
enhanced by automatic idle-mode operation—a vari-
able-frequency pulse-skipping mode that reduces
losses due to MOSFET gate charge. The step-down
power-switching circuit consists of two N-channel
MOSFETs, a rectifier, and an LC output filter. The out-
put voltage is the average of the AC voltage at the
switching node, which is adjusted and regulated by
changing the duty cycle of the MOSFET switches. The
gate-drive signal to the N-channel high-side MOSFET
must exceed the battery voltage and is provided by a
flying capacitor boost circuit that uses a 100nF capaci-
tor connected to BST.
Figure 1. Standard 3.3V Application Circuit (see Table 1 for Component Values)
MAX1652–MAX1655
High-Efficiency, PWM, Step-Down
DC-DC Controllers in 16-Pin QSOP
Table 1. Component Selection for Standard Applications
Table 2. Component Suppliers* Distributor
MAX1652–MAX1655
High-Efficiency, PWM, Step-Down
DC-DC Controllers in 16-Pin QSOPThe MAX1652–MAX1655 contain nine major circuit
blocks, which are shown in Figure 2:
PWM Controller Blocks:Multi-Input PWM ComparatorCurrent-Sense CircuitPWM Logic BlockDual-Mode Internal Feedback MuxGate-Driver OutputsSecondary Feedback Comparator
Bias Generator Blocks: +5V Linear RegulatorAutomatic Bootstrap Switchover Circuit +2.50V Reference
These internal IC blocks aren’t powered directly from
the battery. Instead, a +5V linear regulator steps down
the battery voltage to supply both the IC internal rail (VL
pin) as well as the gate drivers. The synchronous-
switch gate driver is directly powered from +5V VL,
while the high-side-switch gate driver is indirectly pow-
ered from VL via an external diode-capacitor boost cir-
cuit. An automatic bootstrap circuit turns off the +5V
linear regulator and powers the IC from its output volt-
age if the output is above 4.5V.
PWM Controller BlockThe heart of the current-mode PWM controller is a
multi-input open-loop comparator that sums three sig-
nals: output voltage error signal with respect to the ref-
erence voltage, current-sense signal, and slope
compensation ramp (Figure 3). The PWM controller is a
direct summing type, lacking a traditional error amplifi-
er and the phase shift associated with it. This direct-
summing configuration approaches the ideal of
cycle-by-cycle control over the output voltage.
Under heavy loads, the controller operates in full PWM
mode. Each pulse from the oscillator sets the main
PWM latch that turns on the high-side switch for a peri-
od determined by the duty factor (approximately
VOUT/VIN). As the high-side switch turns off, the syn-
chronous rectifier latch is set. 60ns later the low-side
switch turns on, and stays on until the beginning of the
next clock cycle (in continuous mode) or until the
inductor current crosses zero (in discontinuous mode).
Under fault conditions where the inductor current
exceeds the 100mV current-limit threshold, the high-
side latch resets and the high-side switch turns off.
If the load is light in Idle Mode (SKIP= low), the induc-
tor current does not exceed the 25mV threshold set by
the Idle Mode comparator. When this occurs, the con-
troller skips most of the oscillator pulses in order to
reduce the switching frequency and cut back gate-
charge losses. The oscillator is effectively gated off at
light loads because the Idle Mode comparator immedi-
ately resets the high-side latch at the beginning of each
cycle, unless the feedback signal falls below the refer-
ence voltage level.
When in PWM mode, the controller operates as a fixed-
frequency current-mode controller where the duty ratio
is set by the input/output voltage ratio. The current-
mode feedback system regulates the peak inductor
current as a function of the output voltage error signal.
Since the average inductor current is nearly the same
as the peak current, the circuit acts as a switch-mode
transconductance amplifier and pushes the second out-
put LC filter pole, normally found in a duty-factor-
controlled (voltage-mode) PWM, to a higher frequency.
To preserve inner-loop stability and eliminate regenera-
tive inductor current “staircasing,” a slope-compensa-
tion ramp is summed into the main PWM comparator to
reduce the apparent duty factor to less than 50%.
The relative gains of the voltage- and current-sense
inputs are weighted by the values of current sources
that bias three differential input stages in the main PWM
comparator (Figure 4). The relative gain of the voltage
comparator to the current comparator is internally fixed
at K = 2:1. The resulting loop gain (which is relatively
low) determines the 2% typical load regulation error.
The low loop-gain value helps reduce output filter
capacitor size and cost by shifting the unity-gain
crossover to a lower frequency.
The output filter capacitor C2 sets a dominant pole in
the feedback loop. This pole must roll off the loop gain
to unity before the zero introduced by the output
capacitor’s parasitic resistance (ESR) is encountered
(see Design Proceduresection). A 12kHz pole-zero
cancellation filter provides additional rolloff above the
unity-gain crossover. This internal 12kHz lowpass com-
pensation filter cancels the zero due to the filter capaci-
tor’s ESR. The 12kHz filter is included in the loop in
both fixed- and adjustable-output modes.
Synchronous-Rectifier Driver (DL Pin) Synchronous rectification reduces conduction losses in
the rectifier by shunting the normal Schottky diode with
a low-resistance MOSFET switch. The synchronous rec-
tifier also ensures proper start-up of the boost-gate driv-
er circuit. If you must omit the synchronous power
MOSFET for cost or other reasons, replace it with a
small-signal MOSFET such as a 2N7002.
If the circuit is operating in continuous-conduction mode,
the DL drive waveform is simply the complement of the
DH high-side drive waveform (with controlled dead
time to prevent cross-conduction or “shoot-through”).
MAX1652–MAX1655
High-Efficiency, PWM, Step-Down
DC-DC Controllers in 16-Pin QSOP
MAX1652–MAX1655
High-Efficiency, PWM, Step-Down
DC-DC Controllers in 16-Pin QSOP
