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MAX1643 の電気的特性と機能

MAX1643のメーカーはMaxim Integratedです、この部品の機能は「Step-Up DC-DC Converters」です。


製品の詳細 ( Datasheet PDF )

部品番号 MAX1643
部品説明 Step-Up DC-DC Converters
メーカ Maxim Integrated
ロゴ Maxim Integrated ロゴ 




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MAX1643 Datasheet, MAX1643 PDF,ピン配置, 機能
19-1183; Rev 0; 6/97
EVFAOLLULAOTWIOSNDKAITTAMSAHNEUEATL
High-Efficiency, Step-Up
DC-DC Converters for 1V Inputs
_______________General Description
The MAX1642/MAX1643 are high-efficiency, low-voltage,
step-up DC-DC converters intended for devices pow-
ered by a single alkaline cell. They feature low quies-
cent supply currents and are supplied in the ultra-small
µMAX package, which is only 1.1mm high. The guaran-
teed start-up voltage is 0.88V.
Each device consists of an internal 1, N-channel
MOSFET power switch; a built-in synchronous rectifier
that acts as the catch diode; an oscillator; a reference;
and pulse-frequency-modulation (PFM) control circuitry.
Both devices feature an independent undervoltage
comparator (PFI/PFO). The MAX1642 also includes a
2µA logic-controlled shutdown mode. The MAX1643
offers a dedicated low-battery detector (BATTLO) in
lieu of shutdown.
The output voltage for each device is preset to 3.3V
±4%, or can be adjusted from +2V to +5.2V using only
two resistors.
________________________Applications
Pagers
Remote Controls
Pointing Devices
Personal Medical Monitors
Single-Cell Battery-Powered Devices
____________________________Features
o Built-In Synchronous Rectifier
o 0.88V Guaranteed Start-Up
o Ultra-Small µMAX Package: 1.1mm High
o 83% Efficiency
o 4µA Quiescent Supply Current into BATT Pin
o 2µA Logic-Controlled Shutdown (MAX1642)
o Two Undervoltage Detectors (MAX1643)
o 2V to 5.2V Output Range
o 20mA Output Current at 1.2V Input
o Reverse Battery Protection
______________Ordering Information
PART
MAX1642C/D
MAX1642EUA
MAX1643C/D
MAX1643EUA
TEMP. RANGE
0°C to +70°C
-40°C to +85°C
0°C to +70°C
-40°C to +85°C
PIN-PACKAGE
Dice*
8 µMAX
Dice*
8 µMAX
*Dice are tested at TA = +25°C.
Note: To order these devices shipped in tape and reel, add a -T
to the part number.
_________________Pin Configurations
TOP VIEW
__________Typical Operating Circuit
INPUT
0.88V TO 1.65V 100µH
22µF
ON
OFF
LOW-BATTERY
DETECTOR INPUT
LX OUT
MAX1642
BATT
SHDN
PFI
GND
PFO
FB
OUTPUT
3.3V
22µF
LOW-BATTERY
DETECTOR OUTPUT
BATT 1
PFI 2
PFO 3
SHDN 4
MAX1642
8 OUT
7 LX
6 GND
5 FB
µMAX
BATT 1
PFI 2
BATTLO 3
PFO 4
MAX1643
8 OUT
7 LX
6 GND
5 FB
µMAX
________________________________________________________________ Maxim Integrated Products 1
For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800.
For small orders, phone 408-737-7600 ext. 3468.
http://www.Datasheet4U.com

1 Page





MAX1643 pdf, ピン配列
High-Efficiency, Step-Up
DC-DC Converters for 1V Inputs
ELECTRICAL CHARACTERISTICS
(VBATT = VSHDN = 1.3V, ILOAD = 0mA, FB = GND, TA = -40°C to +85°C, unless otherwise noted.) (Note 4)
PARAMETER
Output Voltage
FB Set Voltage
N-Channel On-Resistance
P-Channel On-Resistance
On-Time Constant
Quiescent Current into OUT
Quiescent Current into BATT
Shutdown Current into OUT
Shutdown Current into BATT
PFI Trip Voltage
SYMBOL
VOUT
VFB
K
IQOUT
IQBATT
ISHDN,OUT
ISHDN,BATT
CONDITIONS
VFB < 0.1V
External feedback
VOUT = 3.3V
VOUT = 3.3V
0.9V < VBATT < 1.5V (tON = K / VBATT)
VOUT = 3.5V
VOUT = 3.5V (MAX1642)
VBATT = 1.0V (MAX1642)
Falling PFI, hysteresis = 1%
MIN
2.99
1.11
12.4
550
BATTLO Trip Voltage
Falling VBATT, VOUT = 3.3V, hysteresis = 2%
(MAX1643)
0.93
MAX
3.56
1.32
1.5
2.2
38.2
18
6.5
1
3.5
662
1.06
UNITS
V
V
V-µs
µA
µA
µA
µA
mV
V
Note 2: Start-up guaranteed by correlation to measurements of device parameters (i.e., switch on-resistance, on-times, off-times, and
output voltage trip points).
Note 3:
tOFF
=

tON
VOUT
x VBATT
- VBATT

x
RATIO.
This
guarantees
discontinuous
conduction.
Note 4: Specifications to -40°C are guaranteed by design, not production tested.
__________________________________________Typical Operating Characteristics
(Circuit of Figure 4, VBATT = 1.2V, R1 + R2 = 1M, TA = +25°C, unless otherwise noted.)
EFFICIENCY vs. OUTPUT CURRENT
(VOUT = 2.4V)
100
90 VIN = 1.6V
80
70
60
50
40
VIN = 1.0V VIN = 1.2V
30 VIN = 0.85V
20
10 L1 = 100µH
SUMIDA CD54-101
0
0.01
0.1
1
10
OUTPUT CURRENT (mA)
100
EFFICIENCY vs. OUTPUT CURRENT
(VOUT = 2.4V)
100
90 VIN = 1.6V
80
70
60
50
40
VIN = 1.0V VIN = 1.2V
30 VIN = 0.85V
20
10 L1 = 150µH
TDK NLC565050T-151K
0
0.01 0.1
1
10
OUTPUT CURRENT (mA)
100
EFFICIENCY vs. OUTPUT CURRENT
(VOUT = 3.3V)
100
90 VIN = 1.6V
80
70
60
50
40
VIN = 1.0V
VIN = 1.2V
30 VIN = 0.85V
20
10 L1 = 100µH
SUMIDA CD54-101
0
0.01
0.1
1
10
OUTPUT CURRENT (mA)
100
_______________________________________________________________________________________ 3
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3Pages


MAX1643 電子部品, 半導体
High-Efficiency, Step-Up
DC-DC Converters for 1V Inputs
______________________________________________________________Pin Description
PIN
MAX1642 MAX1643
11
22
—3
34
4—
55
66
77
88
NAME
BATT
PFI
BATTLO
PFO
SHDN
FB
GND
LX
OUT
FUNCTION
IC Battery-Power Input. Sense input for BATTLO comparator (MAX1643 only).
Power-Fail Input. When the voltage on PFI drops below 614mV, PFO sinks current.
Open-Drain Battery-Low Output. When the voltage at BATT drops below 1V, BATTLO
sinks current.
Open-Drain Power-Fail Output. Sinks current when PFI drops below 614mV.
Active-Low Shutdown Input. Connect to BATT for normal operation.
Feedback Input for adjustable-output operation. Connect FB to an external resistor voltage
divider between OUT and GND. Connect to GND for fixed-output operation.
Ground
N-Channel MOSFET Switch Drain and P-Channel Synchronous-Rectifier Drain
Power Output. Feedback input for fixed 3.3V operation and IC power input. Connect filter
capacitor close to OUT.
_______________Detailed Description
The MAX1642/MAX1643 each consist of an internal 1,
N-channel MOSFET power switch, a built-in synchro-
nous rectifier that acts as the catch diode, an oscillator,
a reference, and PFM control circuitry (Figure 1).
These devices are optimized for applications with
power-management features that operate from one
alkaline cell, such as pagers, remote controls, and bat-
tery-powered instruments. They are designed to meet
the specific demands of the operating states character-
istic of such systems:
1) Primary battery is good and the load is active: In
this state, the system draws tens of milliamperes,
and the MAX1642/MAX1643 typically offer 80% effi-
ciency.
2) Primary battery is good and the load is sleeping: In
this state, the load is drawing hundreds of microam-
peres, and the DC-DC converter IC draws very low
quiescent current. In many applications, the load is
expected to be in this state most of the time.
Operating Principle
The MAX1642/MAX1643 employ a proprietary pulse-
frequency-modulation (PFM) control scheme that com-
bines the ultra-low quiescent current traditional of
pulse-skipping PFM converters with the high-load effi-
ciency of pulse-width-modulation (PWM) converters.
The on-time and minimum off-times are varied as a
function of the input and output voltages:
tON =
K
VBATT
tOFF(MIN) =
1.2 x K
VOUT - VBATT
where K is typically 25V-µs. This enables the
MAX1642/MAX1643 to maintain high efficiency over a
wide range of loads and input/output voltages. The DC-
DC converter is powered from the OUT pin.
6 _______________________________________________________________________________________
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