MAX1636EAP- ,Low-Voltage / Precision Step-Down Controller for Portable CPU PowerFeaturesThe MAX1636 is a synchronous, buck, switch-mode,' ±1% DC Accuracy (Adjustable Mode)power-su ..
MAX1636EAP+ ,Low-Voltage, Precision Step-Down Controller for Portable CPU PowerApplicationsTypical Operating CircuitNotebook ComputersSubnotebook ComputersVINDesktop ComputersBus ..
MAX1637EEE ,Miniature / Low-Voltage / Precision Step-Down ControllerELECTRICAL CHARACTERISTICS(Circuit of Figure 1, V = V = 5V, SYNC = V , I = 0mA, T = 0°C to +85°C, u ..
MAX1637EEE+ ,Miniature, Low-Voltage, Precision Step-Down Controllerfeatures a logic-controlled and synchro-MAX1637EEE 40°C to +85°C 16 QSOPnizable, fixed-frequency, p ..
MAX1637EEE+T ,Miniature, Low-Voltage, Precision Step-Down ControllerELECTRICAL CHARACTERISTICS (continued)(Circuit of Figure 1, V = V = 5V, SYNC = V , I = 0mA, T = 0°C ..
MAX1638EAG ,High-Speed Step-Down Controller with Synchronous Rectification for CPU PowerApplicationsPentium Pro™, Pentium II™, PowerPC™, Alpha™,TO VDD MAX1638DHand K6™ SystemsWorkstations ..
MAX4380EXT-T ,Ultra-Small / Low-Cost / 210MHz / Single-Supply Op Amps with Rail-to-Rail Outputs and DisableELECTRICAL CHARACTERISTICS–Single Supply (V = +5V, V = 0, V = V /2, V = V /2, R = ∞ to V /2, DISABL ..
MAX4382EEE ,Ultra-Small / Low-Cost / 210MHz / Single-Supply Op Amps with Rail-to-Rail Outputs and DisableMAX4380–MAX438419-2012; Rev 2; 4/03Ultra-Small, Low-Cost, 210MHz, Single-SupplyOp Amps with Rail-to ..
MAX4382EEE+ ,Ultra-Small, Low-Cost, 210MHz, Single-Supply Op Amps with Rail-to-Rail Outputs and DisableELECTRICAL CHARACTERISTICS–Single Supply (V = +5V, V = 0, V = V /2, V = V /2, R = ∞ to V /2, DISABL ..
MAX4382EEE+T ,Ultra-Small, Low-Cost, 210MHz, Single-Supply Op Amps with Rail-to-Rail Outputs and DisableFeaturesThe MAX4380–MAX4384 family of op amps are unity-♦ Low Cost and High Speed:gain-stable devic ..
MAX4382ESD ,Ultra-Small / Low-Cost / 210MHz / Single-Supply Op Amps with Rail-to-Rail Outputs and DisableELECTRICAL CHARACTERISTICS–Single Supply (V = +5V, V = 0, V = V /2, V = V /2, R = ∞ to V /2, DISABL ..
MAX4382ESD+ ,Ultra-Small, Low-Cost, 210MHz, Single-Supply Op Amps with Rail-to-Rail Outputs and DisableMAX4380–MAX438419-2012; Rev 2; 4/03Ultra-Small, Low-Cost, 210MHz, Single-SupplyOp Amps with Rail-to ..
MAX1636EAP-MAX1636EAP-
Low-Voltage / Precision Step-Down Controller for Portable CPU Power
_______________General DescriptionThe MAX1636 is a synchronous, buck, switch-mode,
power-supply controller that generates the CPU supply
voltage in battery-powered systems. It achieves ±1%
output voltage accuracy and offers the excellent load-
transient response needed by upcoming generations of
dynamic-clock CPUs.
Up to 95% efficiency is achieved through synchronous
rectification and Maxim’s proprietary Idle Mode™ con-
trol scheme. Efficiency is greater than 80% over a
1000:1 load-current range, extending battery life in sys-
tem-suspend or standby modes. Excellent dynamic
response corrects output load transients caused by the
latest dynamic-clock CPUs within five 300kHz clock
cycles. Strong, 1A, on-board gate drivers ensure fast,
external N-channel MOSFET switching.
The MAX1636 features a logic-controlled and synchro-
nizable, fixed-frequency, pulse-width-modulation (PWM)
operating mode that reduces noise and RF interference
in sensitive mobile communications and pen-entry appli-
cations. Holding SKIPhigh forces fixed-frequency mode
for lowest noise under all load conditions.
For a low-cost version that omits the +5V VL linear-
regulator block and comes in a smaller 16-pin QSOP
package, refer to the MAX1637 data sheet.
________________________ApplicationsNotebook Computers
Subnotebook Computers
Desktop Computers
Bus-Termination Supplies
____________________________Features±1% DC Accuracy (Adjustable Mode)Output Overvoltage Crowbar ProtectionOutput Undervoltage ShutdownAdjustable Switching Frequency to 340kHzLow-Dropout OperationIdle Mode Pulse-Skipping Operation1.10V to 5.5V Adjustable Output Voltage2.5V/3.3V Dual-Mode Fixed-Output SettingsInternal Digital Soft-Start1.1V ±1% Reference Output3µA (typ) Shutdown Current Open-Drain Power-Good Output (RREESSEETT)
20-Pin SSOP Package
MAX1636
Low-Voltage, Precision Step-Down
Controller for Portable CPU Power19-1268; Rev 0; 8/97
Idle Mode is a trademark of Maxim Integrated Products.
__________________Pin Configuration
__________Typical Operating Circuit
______________Ordering Information
MAX1636
Low-Voltage, Precision Step-Down
Controller for Portable CPU Power
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS(Circuit of Figure 1, V+ = 15V, SYNC = VL = VCC, IVL= 0mA, IREF= 0mA, TA
= 0°C to +85°C, unless otherwise noted. Typical valuesare 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.
V+ to GND ...............................................................-0.3V to 36V
GND to PGND........................................................................±2V
SHDNto GND..........................................................-0.3V to 36V
LX, BST to GND.......................................................-0.3V to 36V
DH, BST to LX.............................................................-0.3V to 6V
VL, VCC, CSL, CSH, FB, SKIPto GND ...................... -0.3V to 6V
DL to GND....................................................-0.3V to (VL + 0.3V)
REF, RESET, SYNC, CC, OVP to GND......-0.3V to (VCC+ 0.3V)
VL Output Current...............................................................50mA
VL Short Circuit to GND..............................................Momentary
REF Output Current ............................................................20mA
REF Short Circuit to GND .............................................Indefinite
Continuous Power Dissipation (TA= +70°C)
SSOP (derate 8.00mW/°C above +70°C).....................640mW
Operating Temperature Range
MAX1636EAP...................................................-40°C to +85°C
Storage Temperature Range.............................-65°C to +160°C
Junction Temperature......................................................+150°C
Lead Temperature (soldering, 10sec).............................+300°C
MAX1636
Low-Voltage, Precision Step-Down
Controller for Portable CPU Power
ELECTRICAL CHARACTERISTICS (continued)(Circuit of Figure 1, V+ = 15V, SYNC = VL = VCC, IVL= 0mA, IREF= 0mA, TA
= 0°C to +85°C, unless otherwise noted. Typical valuesare at TA= +25°C.)
MAX1636
Low-Voltage, Precision Step-Down
Controller for Portable CPU Power
ELECTRICAL CHARACTERISTICS (continued)(Circuit of Figure 1, V+ = 15V, SYNC = VL = VCC, IVL= 0mA, IREF= 0mA, TA
= 0°C to +85°C, unless otherwise noted. Typical valuesare at TA= +25°C.)
ELECTRICAL CHARACTERISTICS(Circuit of Figure 1, V+ = 15V, SYNC = VL = VCC, IVL= 0mA, IREF= 0mA, TA
=-40°C to +85°C, unless otherwise noted.) (Note 1)
MAX1636
Low-Voltage, Precision Step-Down
Controller for Portable CPU Power
ELECTRICAL CHARACTERISTICS (continued)
(Circuit of Figure 1, V+ = 15V, SYNC = VL = VCC, IVL= 0mA, IREF= 0mA, TA= -40°C to +85°C, unless otherwise noted.) (Note 1)
__________________________________________Typical Operating Characteristics
(Circuit of Figure 1, VIN= 7V, TA= +25°C, unless otherwise noted.)
Note 1:Specifications to -40°C are guaranteed by design and not production tested.
MAX1636
Low-Voltage, Precision Step-Down
Controller for Portable CPU Power
_____________________________Typical Operating Characteristics (continued)
(Circuit of Figure 1, VIN= 7V, TA = +25°C, unless otherwise noted.)
MAX1636
Low-Voltage, Precision Step-Down
Controller for Portable CPU Power
_____________________________Typical Operating Characteristics (continued)
(Circuit of Figure 1, VIN= 7V, TA = +25°C, unless otherwise noted.)
MAX1636
Low-Voltage, Precision Step-Down
Controller for Portable CPU Power
______________________________________________________________Pin Description
______Standard Application Circuit
The basic MAX1636 buck converter (Figure 1) is easily
adapted to meet a wide range of applications with
inputs up to 30V by substituting components from
Table 1. These circuits represent a good set of trade-
offs between cost, size, and efficiency, while staying
within the worst-case specification limits for stress-
related parameters, such as capacitor ripple current.
Do not change the circuits’ switching frequency without
first recalculating component values (particularly induc-
tance value at maximum battery voltage). Adding a
Schottky rectifier across the synchronous rectifier
improves circuit efficiency by approximately 1%. This
rectifier is otherwise not needed because the MOSFET
required typically incorporates a high-speed silicon
diode from drain to source. Use a Schottky rectifier
rated at a DC current equal to at least one-third of the
load current.
MAX1636
Low-Voltage, Precision Step-Down
Controller for Portable CPU Power
Table 1. Component Selection for Standard Applications
_______________Detailed Description
The MAX1636 is a BiCMOS, switch-mode, power-sup-
ply controller designed primarily for buck-topology reg-
ulators in battery-powered applications where high
efficiency and low quiescent supply current are critical.
Light-load efficiency is enhanced by automatic Idle
Mode operation, a variable-frequency, pulse-skipping
mode that reduces transition and gate-charge losses.
The step-down, power-switching circuit consists of two
N-channel MOSFETs, a rectifier, and an LC output filter.
The output voltage is the average AC voltage at the
switching node, which is regulated by changing the
duty cycle of the MOSFET switches. The gate-drive sig-
nal to the N-channel high-side MOSFET, which must
exceed the battery voltage, is provided by a flying-
capacitor boost circuit that uses a 100nF capacitor
between BST and LX. The MAX1636 contains 10 major
circuit blocks (Figure 2).
The pulse-width-modulation (PWM) controller consists
of a Dual Mode™ feedback network and multiplexer, a
multi-input PWM comparator, high-side and low-side
gate drivers, and logic. The MAX1636 contains fault-
protection circuits that monitor the PWM output for
undervoltage and overvoltage. Bias generator blocks
include the 5V (VL) linear regulator and the 1.1V preci-
sion reference. The PWM uses a 200kHz/300kHz syn-
chronizable oscillator. The circuit blocks are powered
from an internal IC power rail that receives power from
either VL or VCC. The synchronous-switch gate driver is
powered directly from VL, while the high-side-switch
gate driver is powered indirectly from VL via an external
diode-capacitor boost circuit.
MAX1636
Low-Voltage, Precision Step-Down
Controller for Portable CPU Power
Table 2. Component Suppliers
Figure 1. Standard Application Circuit
Dual Mode is a trademark of Maxim Integrated Products.
MAX1636
Low-Voltage, Precision Step-Down
Controller for Portable CPU Power
Figure 2. Functional Diagram
PWM Controller
The heart of the current-mode PWM controller is a
multi-input, open-loop comparator that sums four sig-
nals: the output voltage error signal with respect to the
reference voltage, the current-sense signal, the inte-
grated voltage-feedback signal, and the slope-
compensation ramp (Figure 3).
The PWM controller is a direct-summing type, lacking a
traditional error amplifier and the phase shift associat-
ed with it. This direct-summing configuration approach-
es ideal cycle-by-cycle control over the output voltage
(Figure 4).
When SKIP= low, Idle Mode circuitry automatically
optimizes efficiency throughout the load-current range.
Idle Mode dramatically improves light-load efficiency
MAX1636
Low-Voltage, Precision Step-Down
Controller for Portable CPU Power
Figure 3. PWMController Functional Diagram
