MAX4944ELA+T [MAXIM]
Buffer/Inverter Based Peripheral Driver, BICMOS, PDSO8, 2 X 2 MM, ROHS COMPLIANT, UDFN-8;
| 型号： | MAX4944ELA+T |
| 厂家： | 
MAXIM INTEGRATED PRODUCTS |
| 描述： | Buffer/Inverter Based Peripheral Driver, BICMOS, PDSO8, 2 X 2 MM, ROHS COMPLIANT, UDFN-8 信息通信管理 光电二极管 |
| 文件： | 总10页 (文件大小：157K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
19-0552; Rev 3; 6/08
Overvoltage-Protection Controllers with
Internal FET
3–65L/MAX49
General Description
Features
The MAX4943–MAX4946/MAX4949 family of overvolt-
age-protection devices feature a low 80mΩ (typ) R
♦ Input Voltage Protection Up to +28V
♦ Integrated nFET Switch
ON
internal FET and protect low-voltage systems against
voltage faults up to +28V. These devices also drive an
optional external pFET to protect down to -28V when
connected to a load with reverse current protection.
When the input voltage exceeds the overvoltage thresh-
old, the internal FET is turned off to prevent damage to
the protected components.
♦ Preset Overvoltage Protection Trip Level
7.40V (MAX4943)
6.35V (MAX4944_)
5.80V (MAX4945_)
4.56V (MAX4946)
8.90V (MAX4949)
All switches feature a minimum 1.2A current-limit pro-
tection. During a short-circuit occurrence, the
MAX4944B and MAX4945B place the switch in a
latchoff state where the switch turns off and remains off.
For the autoretry devices, the switch turns off and con-
tinuously checks after a 15ms (typ) retry time.
♦ Low-Current Undervoltage-Lockout Mode
♦ Short-Circuit Protection (Latchoff/Autoretry)
♦ Internal 15ms (typ) Startup Delay and Retry Times
♦ Input Voltage Power-Good Logic Output
♦ Thermal-Shutdown Protection
The overvoltage thresholds (OVLO) are preset to 7.4V,
6.35V, 5.8V, 4.56V, or 8.9V. The undervoltage-lockout
(UVLO) thresholds are preset to 2.45V and 4.15V.
When the input voltage drops below the undervoltage-
lockout (UVLO) threshold, the devices enter a low-
current standby mode. (See the Ordering Information/
Selector Guide for more details on UVLO/OVLO).
♦ Small, 8-Pin (2mm x 2mm) µDFN Package
Pin Configuration
TOP VIEW
+
All devices are offered in a small, 8-pin µDFN (2mm x
2mm) package and are specified for operation over the
-40°C to +85°C temperature range.
1
2
3
4
8
7
6
5
OUT
OUT
OUT
GND
IN
IN
MAX4943–
MAX4946/
MAX4944L/
MAX4945A/
MAX4945L/
MAX4949
GP
Applications
ACOK
Cell Phones
PDAs and Palmtop Devices
µDFN
2mm × 2mm
Digital Still Cameras MP3 Players
Ordering Information/Selector Guide
PART
PIN-PACKAGE
8 µDFN
8 µDFN
8 µDFN
8 µDFN
8 µDFN
8 µDFN
8 µDFN
8 µDFN
8 µDFN
8 µDFN
TOP MARK
ABA
PKG CODE
L822-1
L822-1
L822-1
L822-1
L822-1
L822-1
L822-1
L822-1
L822-1
L822-1
UVLO (V)
4.15
OVLO (V)
7.40
OVERCURRENT MODE
MAX4943ELA+T*
MAX4944ELA+T
MAX4944BELA+T*
MAX4944LELA+T
MAX4945ELA+T**
MAX4945AELA+T**
MAX4945BELA+T*
MAX4945LELA+T
MAX4946ELA+T
MAX4949ELA+T
Retry
Retry
ABB
4.15
6.35
ABC
4.15
6.35
Latchoff
Retry
ABD
2.45
6.35
ABE
4.15
5.80
Retry
ADW
ABF
4.15
5.80
Retry
4.15
5.80
Latchoff
Retry
ABG
2.45
5.80
ABH
2.45
4.56
Retry
ADT
2.45
8.90
Latchoff
Note: All devices are specified over the -40°C to +85°C operating temperature range.
+Denotes a lead-free/RoHS-compliant package.
T = Tape-and-reel package.
*Future product—contact factory for availability.
**The OVLO is 6.10V (max) for the MAX4945ELA+T and .6.0V (max) for the MAX4945AELA+T.
________________________________________________________________ Maxim Integrated Products
1
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.
Overvoltage-Protection Controllers with
Internal FET
ABSOLUTE MAXIMUM RATINGS
IN............................................................................-0.3V to +30V
OUT ...............................................................-0.3V to (IN + 0.3V)
GP...........................................................................-0.3V to +12V
IN to GP..................................................................-0.3V to +22V
ACOK .......................................................................-0.3V to +6V
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
Continuous Power Dissipation (T = +70°C)
A
8-Pin µDFN (derate 4.8mW/°C above +70°C) ..............381mW
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.
ELECTRICAL CHARACTERISTICS
(V = +5V (MAX4943/MAX4944_/MAX4945_/MAX4949), V = +3V (MAX4946), T = -40°C to +85°C, unless otherwise noted.
IN
IN
A
Typical values are at T = +25°C.) (Note 1)
A
PARAMETER
Input Voltage Range
SYMBOL
CONDITIONS
MIN
TYP
MAX
28.0
150
150
30
UNITS
V
2.2
V
IN
V
V
V
= 3V (MAX4946)
= 5V, all remaining parts
= 2.2V
50
50
IN
IN
IN
Input Supply Current
UVLO Supply Current
I
IN
µA
µA
I
UVLO
MAX4943/MAX4944/
MAX4944B/MAX4945/
MAX4945A/ MAX4945B
3.90
2.30
4.15
4.40
2.60
IN Undervoltage Lockout
V
(V falling)
IN
V
UVLO
MAX4944L/MAX4945L/
MAX4946/MAX4949
2.45
1
IN Undervoltage-Lockout
Hysteresis
%
MAX4943
7.00
6.00
5.50
5.50
4.30
8.20
7.4
6.35
5.80
5.80
4.56
8.90
1
7.80
6.70
6.10
6.00
4.82
9.60
MAX4944_
MAX4945/MAX4945B/L
MAX4945A
Overvoltage Trip Level
V
(V rising)
IN
V
OVLO
MAX4946
MAX4949
IN Overvoltage Hysteresis
Switch On-Resistance
%
V
V
= 3V (MAX4946), I
= 1A
OUT
80
200
200
4.0
4.0
5.0
5.0
19
IN
IN
R
mΩ
ON
= 5V, all remaining parts, I
= 1A
80
OUT
T
A
T
A
T
A
T
A
= +25°C
1.2
1.2
2.0
2.0
13
1.7
1.7
3.5
3.0
16
MAX4943–MAX4946
MAX4949
= T
to T
MAX
MIN
Overcurrent Protection Threshold
I
A
LIM
= +25°C
= T to T
MIN
MAX
GP Clamp Voltage
I
(V - V ), V = 28V
V
GPD
IN
GP
IN
GP Pulldown Resistor
R
GPD
50
kΩ
3–65L/MAX49
2
_______________________________________________________________________________________
Overvoltage-Protection Controllers with
Internal FET
3–65L/MAX49
ELECTRICAL CHARACTERISTICS (continued)
(V = +5V (MAX4943/MAX4944_/MAX4945_/MAX4949), V = +3V (MAX4946), T = -40°C to +85°C, unless otherwise noted.
IN
IN
A
Typical values are at T = +25°C.) (Note 1)
A
PARAMETER
ACOK Output-Low Voltage
ACOK High-Leakage Current
Thermal Shutdown
SYMBOL
CONDITIONS
MIN
TYP
MAX
0.4
1
UNITS
V
V
I
= 1mA
OL
SINK
V
= 5.5V
µA
ACOK
+175
40
°C
Thermal-Shutdown Hysteresis
Load Capacitor
°C
300
µF
TIMING CHARACTERISTICS (Figure 2)
Time from V
pump enable
< V < V to charge-
OVLO
UVLO
IN
Debounce Time
t
15
6
ms
ms
INDBC
V
< V < V
, R
= 100Ω,
UVLO
IN
OVLO LOAD
Switch Turn-On Time
t
C
= 300µF, V
= from 10% of V
OUT OUT
ON
LOAD
to 80% of V
OUT
ACOK Assertion Time
t
V
< V < V , to ACOK low
OVLO
30
2
ms
µs
ACOK
UVLO
IN
V
< V
or V > V
IN
, to internal
OVLO
IN
UVLO
20
switch off
Switch Turn-Off Time
Autoretry Time
t
OFF
Overcurrent fault to internal switch turn-off
10
15
µs
From overcurrent fault to internal switch
turn-on
t
ms
RETRY
Note 1: All specifications are 100% production tested at T = +25°C, unless otherwise noted. Specifications are over -40°C to +85°C
A
and are guaranteed by design.
Typical Operating Characteristics
(T = +25°C, unless otherwise noted.)
A
SUPPLY CURRENT
vs. SUPPLY VOLTAGE
R
NORMALIZED UVLO THRESHOLD
vs. TEMPERATURE
ON
vs. TEMPERATURE
300
140
120
1.010
1.008
1.006
1.004
1.002
1.000
0.998
0.996
0.994
0.992
0.990
MAX4944
270
240
210
180
150
120
90
100
80
60
40
20
0
60
30
0
2
6
10
14
18
22
26
-40
-15
10
35
60
85
-40
-15
10
35
60
85
SUPPLY VOLTAGE (V)
TEMPERATURE (°C)
TEMPERATURE (°C)
_______________________________________________________________________________________
3
Overvoltage-Protection Controllers with
Internal FET
Typical Operating Characteristics (continued)
(T = +25°C, unless otherwise noted.)
A
DEBOUNCE TIME
vs. TEMPERATURE
ACOK ASSERTION TIME
vs. TEMPERATURE
NORMALIZED OVLO THRESHOLD
vs. TEMPERATURE
1.010
25
23
40
38
1.008
1.006
1.004
1.002
1.000
0.998
0.996
0.994
0.992
0.990
21
36
34
32
19
17
15
30
-40
-15
10
35
60
85
-40
-15
10
35
60
85
-40
-15
10
35
60
85
TEMPERATURE (°C)
TEMPERATURE (°C)
TEMPERATURE (°C)
POWER-UP RESPONSE
UNDERVOLTAGE FAULT RESPONSE
MAX4943 toc07
MAX4943 toc08
5V
3V
ADAPTER
5V/div
ADAPTER
2V/div
5V
3V
V
IN
V
IN
2V/div
5V/div
V
OUT
V
OUT
5V/div
5V/div
0
V
ACOK
V
ACOK
5V/div
5V/div
0
0
I
OUT
I
OUT
1A/div
2A/div
10ms/div
4μs/div
OVERCURRENT DURATION TIME
(DURING AUTORETRY)
SHORT-CIRCUIT FAULT RESPONSE
MAX4943 toc09
MAX4943 toc10
R
LOAD
= 1Ω
C
OUT
= 0.1μF
ADAPTER
2V/div
V
OUT
1V/div
V
IN
5V/div
V
OUT
5V/div
V
ACOK
5V/div
I
OUT
1A/div
I
OUT
10A/div
C
IN
= 1000μF
1μs/div
10μs/div
3–65L/MAX49
4
_______________________________________________________________________________________
Overvoltage-Protection Controllers with
Internal FET
3–65L/MAX49
Pin Description
PIN
NAME
FUNCTION
Voltage Input. IN powers the charge pump required to turn on the internal switch. When the correct
adapter is plugged in, a 15ms (typ) debouncer prevents false turn-on of the internal switch. Bypass
IN to GND with a 1µF ceramic capacitor as close as possible to the device to enable 15kV (HBM)
ESD protection on IN.
1, 2
IN
3
4
GP
pFET Gate-Drive Output. GP pulls the external pFET gate down when the input is above ground.
Active-Low Open-Drain Adapter-Voltage Indicator Output. ACOK is driven low after the adapter
ACOK
voltage is stable between V
and V
for 30ms (typ). Connect a pullup resistor from ACOK to
OVLO
UVLO
the logic I/O voltage of the host system.
5
GND
OUT
Ground
6, 7, 8
Output Voltage. Output of internal switch. Short all pins together for proper operation.
OUT
IN
CHARGE
PUMP
GP
CHARGE-PUMP
ENABLED
15ms (typ)
OVERCURRENT
OR
THERMAL
FAULTS
DEBOUNCE
TIMER AND
RETRY TIME
RESET
GND
+
-
V
OVLO
OSCILLATOR
V
UVLO
+
RESET
30ms (typ)
TIMER
-
ACOK
MAX4943–MAX4946/MAX4944L/
MAX4945L/MAX4949
Figure 1. Functional Diagram
optional external pFET to protect down to -28V. If the
adapter voltage drops below ground, the pFET turns off
to prevent damage to the protected components due to
negative voltage exposure. The internal charge pump’s
15ms (typ) debounce time prevents false turn-on of the
internal switch during startup. An open-drain, active-low
logic output is available to signal that a successful
power-up has occurred.
Detailed Description
The MAX4943–MAX4946/MAX4949 overvoltage-protec-
tion devices feature a low R
internal FET and protect
ON
low-voltage systems against voltage faults up to +28V. If
the input voltage exceeds the overvoltage threshold, the
internal MOSFET is turned off to prevent damage to the
protected components. These devices also drive an
_______________________________________________________________________________________
5
Overvoltage-Protection Controllers with
Internal FET
OVLO
UVLO
t
OFF
IN
t
OFF
t
ON
80% V
IN
10% V
IN
OUT
t
INDBC
t
t
INDBC
INDBC
t
ACOK
t
ACOK
ACOK
Figure 2. Timing Diagram
voltage above the input voltage. The internal switch is
equipped with 1.2A (min) current-limit protection that
turns off the switch within 10µs (typ) during an overcur-
rent fault condition.
Device Operation
The MAX4943–MAX4946/MAX4949 have an internal
oscillator and charge pump that control the turn-on
of the internal switch. The internal oscillator controls
the timers that enable the turn-on of the charge pump
and controls the state of the open-drain ACOK
Autoretry
The MAX4943–MAX4946 have an overcurrent autoretry
function that turns on the switch again after a 15ms (typ)
retry time (see Figure 3). If the faulty load condition is still
present after the blanking time, the switch turns off again
and the cycle is repeated. The fast turn-off time and
15ms retry time result in a very low duty cycle to keep
power consumption low. If the faulty load condition is not
present, the switch remains on.
output. If V < V
or if V >V
, the internal
OVLO
IN
UVLO
IN
oscillator remains off, thus disabling the charge pump.
If V < V < V , the internal charge pump is
UVLO
IN
OVLO
enabled. The charge-pump startup, after a 15ms (typ)
internal delay, turns on the internal switch (see Figure 2).
ACOK is held high during startup until the ACOK 30ms
(typ) blanking period expires. At this point, the device is
in its on state.
At any time, if V drops below V
OVLO
is disabled.
or rises above
UVLO
Latch
The MAX4944B/MAX4945B/MAX4949 do not have the
autoretry function, and the switch latches off after an
overcurrent fault. The switch remains off until the over-
current fault has been removed. The switch turns back
IN
V
, ACOK is pulled high and the charge pump
Internal Switch
The MAX4943–MAX4946/MAX4949 incorporate an
on when the adapter voltage goes below V
then returns to the valid operating range.
and
UVLO
internal nFET with a 80mΩ (typ) R . The switch is
ON
internally driven by a charge pump that generates a 5V
3–65L/MAX49
6
_______________________________________________________________________________________
Overvoltage-Protection Controllers with
Internal FET
3–65L/MAX49
GP GATE Drive
When the input voltage goes above ground, GP pulls
t
OFF
SWITCH ON
low and turns on the pFET. An internal clamp protects
the pFET by ensuring that the GP to IN voltage does not
exceed 19V (max) when the input (IN) rises to +28V.
SWITCH ON
Undervoltage Lockout (UVLO)
The MAX4944L/MAX4945L/MAX4946/MAX4949 have a
2.45V (typ) undervoltage-lockout threshold (V
),
UVLO
UVLO
while the remaining devices have a 4.15V (typ) V
t
RETRY
SWITCH OFF
threshold. When V is less than V
IN
, ACOK is high
UVLO
impedance.
Overvoltage-Lockout Thresholds (OVLO)
CURRENT
THROUGH
SWITCH
The MAX4943 has a 7.4V (typ) overvoltage threshold
I
LIM
(V
), the MAX4944_ has a 6.35V (typ) V
threshold, the MAX4945_ has a 5.80V (typ) V
threshold, the MAX4946 has a 4.56V (typ) V
threshold, and the MAX4949 has a 8.90V (typ) V
threshold. When V is greater than OVLO, ACOK is
OVLO
OVLO
OVLO
OVLO
OVLO
IN
high impedance.
Figure 3. Autoretry Timing Diagram
ACOK
ACOK is an active-low, open-drain output that asserts
R
1MΩ
R
D
1.5kΩ
C
low when V
< V < V
for the 30ms (typ) peri-
UVLO
IN
OVLO
od. Connect a pullup resistor from ACOK to the logic
I/O voltage of the host system. During a short-circuit
DISCHARGE
RESISTANCE
CHARGE-CURRENT-
LIMIT RESISTOR
fault, ACOK may deassert due to V not being in the
IN
valid operating voltage range.
HIGH-
VOLTAGE
DC
DEVICE
UNDER
TEST
C
s
STORAGE
CAPACITOR
Thermal-Shutdown Protection
The MAX4943–MAX4946/MAX4949 feature thermal-shut-
down circuitry. The internal switch turns off when the junc-
tion temperature exceeds +175°C (typ) and immediately
goes into a fault mode. The device exits thermal shut-
down after the junction temperature cools by 40°C (typ).
100pF
SOURCE
Applications Information
Figure 4. Human Body ESD Test Model
IN Bypass Capacitor
For most applications, bypass IN to GND with a 1µF
ceramic capacitor as close as possible to the device to
enable 15kV (HBM) ESD protection on the pin. If
15kV is not required, there is no capacitor required at
IN. If the power source has significant inductance due
to long lead length, take care to prevent overshoots
due to the LC tank circuit and provide protection if nec-
essary to prevent exceeding the +30V absolute maxi-
mum rating on IN.
I 100%
P
90%
PEAK-TO-PEAK RINGING
(NOT DRAWN TO SCALE)
I
r
AMPERES
36.8%
10%
0
TIME
0
Reverse Polarity Protection
The optional external pFET can provide reverse polarity
protection down to -28V (for a 30V pFET), if the protect-
t
RL
t
DL
CURRENT WAVEFORM
Figure 5. Human Body Current Waveform
_______________________________________________________________________________________
7
Overvoltage-Protection Controllers with
Internal FET
ed device does not allow current to flow into OUT. The
pFET is turned off when the voltage between GP and IN
is less than the pFET gate threshold voltage.
R
R
D
330Ω
C
50MΩ TO 100MΩ
DISCHARGE
RESISTANCE
CHARGE-CURRENT-
LIMIT RESISTOR
ESD Test Conditions
ESD performance depends on a number of conditions.
The MAX4943–MAX4946/MAX4949 are specified for
15kV (HBM) typical ESD resistance on IN when IN is
bypassed to ground with a 1µF ceramic capacitor.
HIGH-
VOLTAGE
DC
DEVICE
UNDER
TEST
C
s
150pF
STORAGE
CAPACITOR
SOURCE
Human Body Model
Figure 4 shows the Human Body Model and Figure 5
shows the current waveform it generates when dis-
charged into a low impedance. This model consists of a
100pF capacitor charged to the ESD voltage of interest,
which is then discharged into the device through a
1.5kΩ resistor.
Figure 6. IEC 61000-4-2 ESD Test Model
Hence, the ESD withstand voltage measured to IEC
61000-4-2 generally is lower than that measured using the
Human Body Model. Figure 6 shows the IEC 61000-4-2
model. The Contact Discharge method connects the
probe to the device before the probe is charged. The
Air-Gap Discharge test involves approaching the device
with a charged probe.
IEC 61000-4-2
The IEC 61000-4-2 standard covers ESD testing and
performance of finished equipment. It does not specifi-
cally refer to integrated circuits. The MAX4943–
MAX4946/MAX4949 are specified for 15kV Air-Gap
Discharge and 8kV Contact Discharge IEC 61000-4-2
on the IN pin when IN is bypassed to ground with a 1µF
ceramic capacitor.
Chip Information
The major difference between tests done using the
Human Body Model and IEC 61000-4-2 is a higher peak
current in IEC 61000-4-2, due to lower series resistance.
PROCESS: BiCMOS
Typical Operating Circuit
5V AC
ADAPTER
1μF
IN
GP
V
I/0
OUT
CHARGER
DC-DC
CONVERTER
15ms (typ)
DEBOUNCE
ACOK
CHARGE
PUMP
TO μC
30ms (typ)
TIMER
MAX4943–MAX4946/MAX4944L/
MAX4945L/MAX4949
GND
3–65L/MAX49
8
_______________________________________________________________________________________
Overvoltage-Protection Controllers with
Internal FET
3–65L/MAX49
Package Information
For the latest package outline information and land patterns, go to www.maxim-ic.com/packages.
PACKAGE TYPE
PACKAGE CODE
DOCUMENT NO.
21-0164
8 µDFN
L822-1
_______________________________________________________________________________________
9
Overvoltage-Protection Controllers with
Internal FET
Revision History
REVISION
NUMBER
REVISION
DATE
PAGES
CHANGED
DESCRIPTION
2
7/07
—
1, 2, 3
Added MAX4945A to the Ordering Information/Selector Guide and Electrical
Characterstics tables
3
6/08
1, 2
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are
implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.
3–65L/MAX49
10 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600
© 2008 Maxim Integrated Products
is a registered trademark of Maxim Integrated Products, Inc.
相关型号：
MAX4944LELA+
Buffer/Inverter Based Peripheral Driver, BICMOS, PDSO8, 2 X 2 MM, ROHS COMPLIANT, UDFN-8
MAXIM
MAX4944LELA+T
Buffer/Inverter Based Peripheral Driver, BICMOS, PDSO8, 2 X 2 MM, ROHS COMPLIANT, UDFN-8
MAXIM
MAX4945AELA+
Buffer/Inverter Based Peripheral Driver, BICMOS, PDSO8, 2 X 2 MM, ROHS COMPLIANT, UDFN-8
MAXIM
MAX4945AELA+T
Buffer/Inverter Based Peripheral Driver, BICMOS, PDSO8, 2 X 2 MM, ROHS COMPLIANT, UDFN-8
MAXIM
MAX4945BELA+T
Buffer/Inverter Based Peripheral Driver, BICMOS, PDSO8, 2 X 2 MM, ROHS COMPLIANT, UDFN-8
MAXIM
MAX4945ELA+T
Buffer/Inverter Based Peripheral Driver, BICMOS, PDSO8, 2 X 2 MM, ROHS COMPLIANT, UDFN-8
MAXIM
MAX4945LELA+
Buffer/Inverter Based Peripheral Driver, BICMOS, PDSO8, 2 X 2 MM, ROHS COMPLIANT, UDFN-8
MAXIM
MAX4945LELA+T
Buffer/Inverter Based Peripheral Driver, BICMOS, PDSO8, 2 X 2 MM, ROHS COMPLIANT, UDFN-8
MAXIM
MAX4946ELA+
Buffer/Inverter Based Peripheral Driver, BICMOS, PDSO8, 2 X 2 MM, ROHS COMPLIANT, UDFN-8
MAXIM
MAX4946ELA+T
Buffer/Inverter Based Peripheral Driver, BICMOS, PDSO8, 2 X 2 MM, ROHS COMPLIANT, UDFN-8
MAXIM
©2020 ICPDF网 联系我们和版权申明