MAX1807EUB+T [MAXIM]

Power Supply Support Circuit, Fixed, 5 Channel, BICMOS, PDSO10, MICRO MAX PACKAGE-10;
MAX1807EUB+T
型号: MAX1807EUB+T
厂家: MAXIM INTEGRATED PRODUCTS    MAXIM INTEGRATED PRODUCTS
描述:

Power Supply Support Circuit, Fixed, 5 Channel, BICMOS, PDSO10, MICRO MAX PACKAGE-10

控制器
文件: 总10页 (文件大小:230K)
中文:  中文翻译
下载:  下载PDF数据表文档文件
19-1791; Rev 0; 10/00  
Micropower Adjustable Overvoltage  
Protection Controllers  
General Description  
Features  
The MAX1807/MAX1808 monitor up to five supply rails  
for an overvoltage condition and provide a latched out-  
put when any one of the five supplies exceeds the trip  
thresholds. The latched output drives an external P-  
channel load switch to remove power when an over-  
voltage condition is detected. The latch is reset when a  
logic low is input to ON or the power supply is cycled.  
o Five 3% Accurate Overvoltage Comparators  
o Series PFET Gate Driver with VGS Limiter  
o 21µA Quiescent Supply Current  
o 4µA Shutdown Current  
o 4.4V to 28V Operating Voltage Range  
The MAX1807 provides a 28V open-drain fault output  
that can be used to trigger an alert, trip a resetable  
fuse, or for other purposes. The MAX1808 includes a  
low-battery comparator with hysteresis to drive the DP  
output high, turning off the external P-channel switch  
when the input voltage is too low.  
o 3% Accurate Comparator with 10% Hysteresis for  
Low-Battery Detection (MAX1808)  
o 28V Open-Drain N-Channel Output (MAX1807)  
o Small 10-Pin µMAX Package  
The MAX1807/MAX1808 are available in a miniature 10-  
pin µMAX package.  
Ordering Information  
________________________Applications  
Notebook Computers  
PART  
TEMP. RANGE  
-40°C to +85°C  
-40°C to +85°C  
PIN-PACKAGE  
10 µMAX  
Power-Supply Modules  
MAX1807EUB  
MAX1808EUB  
Multi-Output Power Supplies  
10 µMAX  
Pin Configuration and Typical Operating Circuit appear at  
end of data sheet.  
Functional Diagram  
V
DD  
2.5V  
ON  
INTERNAL  
POWER-ON  
1V REF  
REF OK  
SUPPLY  
PMOS  
POWER  
DRIVER  
RESET  
DP  
(60µs)  
+
TH  
(MAX1808)  
_
+
IN1  
IN2  
_
R
S
Q
+
_
FAULT  
(MAX1807)  
IN3  
IN4  
IN5  
+
_
+
_
GND  
MAX1807  
MAX1808  
+
_
________________________________________________________________ Maxim Integrated Products  
1
For price, delivery, and to place orders, please contact Maxim Distribution at 1-888-629-4642,  
or visit Maxim’s website at www.maxim-ic.com.  
Micropower Adjustable Overvoltage  
Protection Controllers  
ABSOLUTE MAXIMUM RATINGS  
IN1_, TH to GND.......................................................-0.3V to +6V  
Operating Temperature Range ...........................-40°C to +85°C  
ON, V , FAULT to GND........................................-0.3V to +30V  
Junction Temperature......................................................+150°C  
Storage Temperature Range.............................-65°C to +150°C  
Lead Temperature (soldering, 10s) .................................+300°C  
DD  
DP to GND..................................................-0.3V to (V  
+ 0.3V)  
DD  
Continuous Power Dissipation  
10-Pin µMAX (derate 5.6mW/°C above +70°C)...........448mW  
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  
= V  
= 15V, V –V  
= 0.5V, V = 2.0V, C = 5nF, FAULT = open, T = 0°C to +85°C, unless otherwise noted.)  
DD  
ON  
IN1 IN5 TH DP A  
PARAMETER  
GENERAL  
SYMBOL  
CONDITIONS  
MIN  
TYP  
MAX  
UNITS  
V
V
V
Input Voltage Range  
DP and FAULT in correct state (Table 1)  
2
28  
28  
V
V
DD  
DD  
Operating Voltage Range  
4.4  
Undervoltage Lockout  
Rising trip level, typical 2% hysteresis; when V  
is below this level, DP = Hi and FAU LT = Hi-Z  
DD  
DD  
2
2.7  
4.0  
V
Threshold  
Supply Current  
V
V
= 2V or 0.5V  
21  
4
45  
µA  
µA  
TH  
Shutdown Current  
= 15V, V = GND, V V = V = GND  
8.5  
DD  
ON  
IN1 IN5  
TH  
COMPARATORS (IN1IN5, TH)  
Rising edge, typical 1% hysteresis,  
IN1IN5 Input Trip Level  
0.97  
1
1.03  
V
V
V
V
= 4.4V to 28V  
DD  
DD  
DD  
TH Input Trip Level, Falling  
TH Input Trip Level, Rising  
IN1IN5 Propagation Delay  
= 4.4V to 28V (MAX1808 only)  
= 4.4V to 28V (MAX1808 only)  
0.97  
1
1.03  
V
V
1.045  
1.1  
40  
1.155  
IN1IN5 rising, 10mV overdrive, V  
= 4.4V  
µs  
DD  
TH rising, 10mV overdrive, V = 4.4V  
DD  
(MAX1808 only)  
11  
40  
TH Propagation Delay  
µs  
TH falling, 10mV overdrive, V  
(MAX1808 only)  
= 4.4V  
DD  
IN1IN5 Input Leakage Current  
TH Input Leakage Current  
ON Input High Logic Level  
ON Input Low Logic Level  
V
V
V
V
V
V
= 1.5V  
0.5  
0.5  
50  
50  
nA  
nA  
V
IN  
= 1.5V (MAX1808 only)  
TH  
DD  
DD  
ON  
ON  
= 4.4V to 28V  
= 4.4V to 28V  
= 5V  
1.6  
0.5  
1.2  
10  
V
0.03  
0.01  
ON Input Leakage Current  
µA  
= 28V  
FAULT Output High Leakage  
Current  
V
= 28V (MAX1807 only)  
2
µA  
FAULT  
FAULT Output Low Voltage  
I
= 4mA (MAX1807 only)  
0.4  
V
SINK  
2
_______________________________________________________________________________________  
Micropower Adjustable Overvoltage  
Protection Controllers  
ELECTRICAL CHARACTERISTICS (continued)  
(V  
= V  
= 15V, V V  
= 0.5V, V = 2.0V, C = 5nF, FAULT = open, T = 0°C to +85°C, unless otherwise noted.)  
DD  
ON  
IN1 IN5 TH DP A  
PARAMETER  
SYMBOL  
CONDITIONS  
MIN  
1
TYP  
50  
MAX  
UNITS  
µA  
V
V
= V  
- 0.4V  
- 2V  
DP  
DP  
DD  
DD  
DP Source Current  
(PMOS Turn-Off)  
V
V
= V  
= 1.5V  
,
DD  
ON  
IN1  
= V  
5
20  
mA  
DP Sink Current (PMOS Turn-On)  
V
= V  
- 5V  
4
50  
mA  
DP  
DD  
V
= V  
- 2V, V  
= GND,  
DP  
DD  
ON  
DP Pullup Current (PMOS Off)  
25  
µA  
in shutdown state  
V
V
= 8.5V to 28V  
= 4.4V  
7.5  
3.4  
9.5  
4.1  
11.5  
4.4  
DD  
DD  
DP Turn-On Clamp Voltage  
V
= V  
,
DD  
ON  
V
(V  
DD  
- V  
DP  
)
I
= 10µA  
DPSINK  
ELECTRICAL CHARACTERISTICS  
(V  
= V  
= 15V, V V  
= 0.5V, V = 2.0V, C = 5nF, FAULT = open, T = -40°C to +85°C, unless otherwise noted.) (Note 1)  
DD  
ON  
IN1 IN5 TH DP A  
PARAMETER  
GENERAL  
SYMBOL  
CONDITIONS  
MIN  
TYP  
MAX  
UNITS  
V
V
Input Voltage Range  
DP and FAULT in correct state (Table 1)  
2
28  
28  
V
V
DD  
DD  
Operating Voltage Range  
4.4  
Rising trip level, typical 2% hysteresis; when  
V
Undervoltage Lockout  
DD  
V
DD  
is below this level, DP = Hi and FAU LT =  
2
4.0  
V
Threshold  
Hi-Z  
Supply Current  
V
= 2V or 0.5V  
45  
µA  
µA  
TH  
DD  
Shutdown Current  
V
= 15V, V = GND, V V = V = GND  
8.5  
ON  
IN1 IN5  
TH  
COMPARATORS (IN1IN5, TH)  
IN1IN5 Input Trip Level  
TH Input Trip Level, Falling  
TH Input Trip Level, Rising  
IN1IN5 Input Leakage Current  
TH Input Leakage Current  
ON Input High Logic Level  
ON Input Low Logic Level  
Rising edge, typical 1% hysteresis  
0.95  
0.95  
1.05  
1.05  
1.155  
50  
V
V
V
V
V
V
V
V
V
V
= 4.4V to 28V (MAX1808 only)  
= 4.4V to 28V (MAX1808 only)  
DD  
DD  
1.045  
V
= 1.5V  
nA  
nA  
V
IN  
= 1.5V (MAX1808 only)  
50  
TH  
DD  
DD  
ON  
ON  
= 4.4V to 28V  
= 4.4V to 28V  
= 5V  
1.8  
0.4  
1.2  
10  
V
ON Input Leakage Current  
µA  
µA  
= 28V  
FAULT Output High Leakage  
Current  
V
= 28V (MAX1807 only)  
2
FAULT  
FAULT Output Low Voltage  
I
= 4mA (MAX1807 only)  
0.4  
V
SINK  
V
V
= V  
= V  
- 0.4V  
- 2V  
1
4
µA  
mA  
mA  
DP  
DP  
DD  
DD  
DP Source Current  
(PMOS Turn-Off)  
V
V
= V  
= 1.5V  
,
DD  
ON  
IN1  
DP Sink Current (PMOS Turn-On)  
DP Turn-On Clamp Voltage  
V
V
= V - 5V  
2
DP  
DD  
V
V
= 8.5V to 28V  
= 4.4V  
7.5  
3.4  
11.5  
4.4  
DD  
DD  
= V  
,
DD  
ON  
V
(V  
DD  
- V  
DP  
)
I
= 10µA  
DPSINK  
Note 1: Specifications to -40°C are guaranteed by design, not production tested.  
_______________________________________________________________________________________  
3
Micropower Adjustable Overvoltage  
Protection Controllers  
Typical Operating Characteristics  
(Typical Operating Circuit, V  
= 15V, T = +25°C, unless otherwise noted.)  
A
DD  
SHUTDOWN SUPPLY CURRENT  
vs. SUPPLY VOLTAGE  
FAULT OUTPUT VOLTAGE LOW  
vs. FAULT OUTPUT SINK CURRENT  
SUPPLY CURRENT vs. SUPPLY VOLTAGE  
5.0  
4.5  
4.0  
3.5  
3.0  
2.5  
2.0  
1.5  
1.0  
0.5  
0
700  
600  
500  
400  
300  
200  
100  
0
25  
20  
15  
10  
5
T = +85°C  
A
T
= +85°C  
A
T
= +85°C  
A
T
= +25°C  
A
T
= +25°C  
T
= +25°C  
A
A
T
= -40°C  
A
T
= -40°C  
A
T
= -40°C  
A
0
0
5
10  
15  
20  
25  
30  
0
5
10  
15  
20  
25  
30  
0
4
8
12  
16  
20  
SUPPLY VOLTAGE (V)  
SUPPLY VOLTAGE (V)  
FAULT OUTPUT SINK CURRENT (mA)  
NORMALIZED TH TRIP THRESHOLD  
ERROR vs. SUPPLY VOLTAGE (TH FALLING)  
NORMALIZED IN_ TRIP THRESHOLD  
ERROR vs. SUPPLY VOLTAGE  
NORMALIZED IN_ TRIP THRESHOLD  
ERROR vs. TEMPERATURE  
0.25  
0.20  
0.15  
0.10  
0.05  
0
0.3  
0.2  
0.02  
0.01  
0
0.1  
28V  
0
T
= +25°C  
T
= +25°C  
T
= +85°C  
A
A
A
15V  
-0.1  
-0.2  
-0.3  
-0.4  
-0.05  
-0.10  
-0.15  
-0.20  
-0.25  
4.4V  
T
= -40°C  
A
-0.01  
-0.02  
T
= -40°C  
A
T
= +85°C  
A
0
10  
20  
30  
0
5
10  
15  
20  
25  
30  
-50  
0
50  
100  
SUPPLY VOLTAGE (V)  
SUPPLY VOLTAGE (V)  
TEMPERATURE (°C)  
NORMALIZED TH TRIP THRESHOLD  
ERROR vs. TEMPERATURE (TH FALLING)  
NORMALIZED TH TRIP THRESHOLD  
ERROR vs. SUPPLY VOLTAGE (TH RISING)  
NORMALIZED TH TRIP THRESHOLD  
ERROR vs. TEMPERATURE (TH RISING)  
0.15  
0.10  
0.05  
0
0.20  
0.15  
0.10  
0.05  
0
0.3  
0.2  
0.1  
0
28V  
4.4V  
28V  
T
= +25°C  
= -40°C  
A
T
A
-0.05  
-0.10  
-0.15  
-0.20  
-0.05  
-0.10  
-0.15  
-0.1  
-0.2  
-0.3  
T
= +85°C  
A
4.4V  
-50  
0
50  
100  
0
5
10  
15  
20  
25  
30  
-50  
0
50  
100  
TEMPERATURE (°C)  
SUPPLY VOLTAGE (V)  
TEMPERATURE (°C)  
4
_______________________________________________________________________________________  
Micropower Adjustable Overvoltage  
Protection Controllers  
Typical Operating Characteristics (continued)  
= 15V, T = +25°C, unless otherwise noted.)  
A
(Typical Operating Circuit, V  
DD  
TH PROPAGATION DELAY  
vs. SUPPLY VOLTAGE (TH RISING)  
IN_ PROPAGATION DELAY  
vs. SUPPLY VOLTAGE  
TH PROPAGATION DELAY  
vs. SUPPLY VOLTAGE (TH FALLING)  
16  
14  
12  
10  
8
60  
50  
40  
30  
20  
10  
0
60  
50  
40  
30  
20  
10  
0
T
= +85°C  
A
T
T
= +85°C  
= +25°C  
A
T
= +85°C  
=+25°C  
= -40°C  
A
T
= +25°C  
= -40°C  
A
T
A
A
T
A
T
A
6
T
= -40°C  
A
4
10mV  
OVERDRIVE  
2
10mV  
10mV  
OVERDRIVE  
OVERDRIVE  
0
0
5
10  
15  
20  
25 30  
0
5
10  
15  
20  
25  
30  
0
5
10  
15  
20  
25 30  
SUPPLY VOLTAGE (V)  
SUPPLY VOLTAGE (V)  
SUPPLY VOLTAGE (V)  
DP SINK CURRENT  
DP SOURCE CURRENT  
DP SOURCE CURRENT  
vs. (V - V ) VOLTAGE  
vs. (V - V ) VOLTAGE  
DD  
DP  
vs. (V - V ) VOLTAGE  
DD  
DP  
DD  
DP  
0.10  
0.09  
0.08  
0.07  
0.06  
0.05  
0.04  
0.03  
0.02  
0.01  
0
60  
50  
40  
30  
20  
10  
0
25  
20  
15  
10  
5
0
0
2
4
6
8
10  
12  
0
0.15  
0.30  
0.45  
0.60  
0
2
4
6
8
10  
12  
(V - V ) VOLTAGE (V)  
(V - V ) VOLTAGE (V)  
DD  
DP  
(V - V ) VOLTAGE (V)  
DD DP  
DD  
DP  
IN_ AND TH BIAS CURRENT  
vs. TEMPERATURE  
IN_ MAXIMUM TRANSIENT PULSE  
DURATION vs. PULSE OVERDRIVE VOLTAGE  
100  
TH MAXIMUM TRANSIENT PULSE  
DURATION vs. PULSE OVERDRIVE VOLTAGE  
100  
1.6  
1.4  
1.2  
1.0  
0.8  
0.6  
0.4  
0.2  
0
DP LATCHES (HIGH)  
ABOVE THE CURVE  
DP GOES  
HIGH MOMENTARILY  
ABOVE THE CURVE  
90  
80  
70  
60  
50  
40  
30  
20  
10  
0
90  
80  
70  
60  
50  
40  
30  
20  
10  
0
NEGATIVE-  
GOING  
TRANSIENT  
-40  
-15  
10  
35  
60  
85  
0.001  
0.01  
0.1  
1
0.001  
0.01  
0.1  
1
TEMPERATURE (°C)  
OVERDRIVE VOLTAGE (V)  
OVERDRIVE VOLTAGE (V)  
_______________________________________________________________________________________  
5
Micropower Adjustable Overvoltage  
Protection Controllers  
Pin Description  
PIN  
15  
6
NAME  
IN1IN5  
GND  
FUNCTION  
Overvoltage Detect Comparator Input. When any input exceeds 1V, the fault latch is set. Connect  
unused inputs to GND.  
Ground  
Logic Input. ON turns on internal reference when high. Logic trip level is approximately 1.2V with 15%  
7
ON  
DP  
hysteresis. When ON is low, the fault latch is reset. ON can be connected directly to V at the  
DD  
expense of supply current.  
External P-Channel MOSFET Gate Driver Output. The output high level is V . The output low level is  
DD  
8
9
V
- 9.5V or GND, whichever is higher. This output is latched high when an overvoltage condition is  
DD  
detected.  
Analog Supply Input. Use an external RC filter to eliminate excessive switching noise on V . When  
DD  
V
DD  
V
is less than 2.7V, the fault latch is reset.  
DD  
Signal Overvoltage Condition Output. This open-drain N-channel output is latched low when an over-  
voltage condition is detected. (MAX1807 only)  
FAULT  
10  
Input Monitor Comparator. When TH is below 1V, DP goes high to turn off the external P-channel  
switch. When TH exceeds 1.1V, DP goes low if there is no fault. Between 1V and 1.1V is the hysteresis  
band where the output state of the TH comparator remains unchanged. (MAX1808 only)  
TH  
The MAX1808 has a TH input that turns off the P-chan-  
nel switch if TH goes below 1V without affecting the  
Detailed Description  
The MAX1807/MAX1808 provide overvoltage protection  
for systems with multiple supply rails. Very low output  
voltage supplies can have an overvoltage before the  
power-supply controller has sufficient supply voltage to  
activate protection circuitry. The MAX1807/MAX1808  
offer a system-wide approach to effectively protect the  
loads and prevent catastrophic events.  
fault latch. TH output is designed for low-battery detec-  
tion. The comparator has 10% hysteresis, allowing the  
battery voltage to rise when the load is removed without  
reenabling the external P-channel switch.  
The MAX1807 has a fault alert output (FAULT) instead  
of the TH input. FAULT is an open-drain output, rated  
for up to 28V, that directly reflects the state of the inter-  
nal fault latch.  
The MAX1807/MAX1808 are powered directly by the  
main system input supply. A low output voltage from  
DP activates a P-channel switch to supply power to the  
rest of the system. As the rest of the system supplies  
come up, the MAX1807/MAX1808 monitor each of them  
for overvoltage conditions and safely disconnect the  
input from the rest of the system if any supply malfunc-  
tions occur due to a shorted MOSFET, shorted copper  
trace, or malfunctioning supply. Built-in overvoltage  
detectors in individual power supplies provide redun-  
dancy.  
IN1–IN5 Overvoltage Comparators  
The overvoltage comparators have a 1V trip level. The  
fault latch is set if any one of the five overvoltage com-  
parators goes above the trip level. A limited input band-  
width ensures that small glitches will not trigger an  
overvoltage event (see IN_ Maximum Transient Pulse  
Duration vs. Pulse Overdrive Voltage in the Typical  
Operating Characteristics).  
DP PFET Driver Output  
The MAX1807/MAX1808 have a totem driver (DP) with  
an active clamp that simplifies driving the external P-  
The MAX1807/MAX1808 drive the main P-channel load  
switch that powers the system. The driver includes  
active clamping to safely drive a 12V P-channel MOS-  
FET gate. If overvoltage is detected, the P-channel load  
switch is turned off and the state is latched. The internal  
channel load switch. The -9.5V V clamp eliminates  
gs  
complexity in circuits where V  
exceeds the P-chan-  
DD  
nel FETs maximum gate voltage. DP goes high and  
turns off the P-channel switch during undervoltage  
lockout, when ON is low, when TH is less than 1V, or if  
an overvoltage fault occurs.  
fault latch resets when V  
is less than 2.7V (power  
DD  
cycled) or ON is pulled low (manual reset). When ON  
is logic low, the P-channel switch is turned off (Table 1).  
6
_______________________________________________________________________________________  
Micropower Adjustable Overvoltage  
Protection Controllers  
The DP driver can sink and source significant current  
disconnected from the battery. The comparator has a  
limited bandwidth to ensure that small transients will not  
shut down the system supplies.  
and achieves fast turn-on and turn-off times even with  
large P-channel switches. Adding a resistor in series  
with DP can increase turn-on and turn-off times. To slow  
the turn-on time without affecting the turn-off time, add  
a diode in parallel with the resistor (Figure 1). The turn-  
on time will be the product of the series resistor and the  
gate-to-source capacitance of the P-channel FET:  
Increase TH hysteresis by adding a resistor from TH to  
one of the voltage rails disconnected by the P-channel  
load switch, such as the 1.8V supply (Figure 2). Use  
one of the lower voltage supplies to eliminate the  
necessity of extremely large resistors to obtain reason-  
able hysteresis. When the MAX1714 is on, the trip  
threshold is lower than when the MAX1714 is off, pro-  
t
= C R  
gs  
ON  
The turn-off time will be the product of the gate-to-  
source capacitance of the P-channel FET and the DP  
source current of the MAX1807/MAX1808 (see DP  
Source Current vs. (V  
- V ) Voltage in the Typical  
DP  
DD  
1N4148  
Operating Characteristics).  
V
DD  
For very slow turn-off times, adding an external capaci-  
tor between the gate and the source of the P-channel  
FET eliminates the need for resistors with extremely  
high values.  
DP  
R
MAX1807  
MAX1808  
SYSTEM  
POWER  
SUPPLIES  
TH Input Comparator (MAX1808 Only)  
TH input comparator can disconnect the load from the  
battery when the battery voltage is too low. The falling  
trip level is 1V, and the rising trip level is 1.1V. The  
100mV hysteresis can prevent the load switch from  
turning on when the battery voltage rises as the load is  
Figure 1. External FET Gate Control  
2V TO 28V  
6.5M  
2V TO 28V  
6.5M  
1M  
V
V
DD  
DD  
TH  
DP  
DP  
TH  
1M  
MAX1808  
MAX1808  
MAX1714  
1.8V OR 0  
GND  
GND  
10M  
DEFAULT 10% HYSTERESIS  
ADDING HYSTERESIS  
V
= 1V + [1µA (1.8V - 1.0V) / 10M] 6.5MΩ  
V
V
= 1V + (1µA × 6.5M) = 7.5V  
TRIP  
TRIP  
= 1V + (1µA - 0.08µA) 6.5MΩ  
= 1V + (920nA 6.5M) = 6.98V  
= 1.1V + (1.1µA × 6.5M) = 8.25V  
UNTRIP  
V
= 1.1V + [1.1µA - (0 - 1.1V) / 10M] 6.5MΩ  
UNTRIP  
= 1.1V + (1.1µA + 0.11µA) 6.5MΩ  
= 1.1V + (1.21µA 6.5M) = 8.97V  
Figure 2. Adding Hysteresis  
_______________________________________________________________________________________  
7
Micropower Adjustable Overvoltage  
Protection Controllers  
Table 1. MAX1807/MAX1808 State Table  
V
ON  
X
TH  
X
IN1IN5  
DP  
FAULT  
COMMENT  
DD  
<2V  
< 4.0V  
X
Undefined Undefined  
2 < V  
X
X
X
X
HI  
HI  
Hi-Z  
Hi-Z  
DD  
>4.0V  
>4.0V  
>4.0V  
>4.0V  
0
X
1
<1V  
>1.1V  
>1.1V  
X
HI  
Note that TH has 0.1V hysteresis (MAX1808 only)  
1
All <1V  
Any >1V  
LO  
HI  
Hi-Z  
LO  
Only condition for PFET to be turned on  
1
viding additional hysteresis. Turning off the chosen  
supply will change the undervoltage trip levels.  
Pin Configuration  
FAULT Open-Drain N-Channel  
Flag Output (MAX1807 Only)  
TOP VIEW  
The MAX1807 has an open-drain N-channel FAULT  
output. The FAULT output directly reflects the state of  
the internal fault latch, going low when an overvoltage  
event occurs. The FAULT output can be used to signal  
the system power-management microcontroller, trip a  
resetable fuse, drive an external high-side driver, or for  
other purposes.  
IN1  
IN2  
IN3  
IN4  
IN5  
1
2
3
4
5
10 FAULT (TH)  
9
8
7
6
V
DD  
MAX1807  
MAX1808  
DP  
ON  
GND  
Undervoltage Lockout and Power-On  
Reset (POR) Period  
Undervoltage lockout holds DP high and FAULT in high  
µMAX  
( ) MAX1808 0NLY  
impedance until V  
exceeds the V  
undervoltage  
DD  
DD  
lockout threshold. When V  
exceeds the undervoltage  
DD  
threshold, the DP and FAULT outputs remain un-  
changed during the power-on reset period (60µs),  
allowing the reference and comparators to settle.  
Normal operation resumes after the POR period.  
Chip Information  
TRANSISTOR COUNT: 955  
PROCESS: BiCMOS  
8
_______________________________________________________________________________________  
Micropower Adjustable Overvoltage  
Protection Controllers  
Typical Operating Circuit  
5V  
2.5V  
1.8V  
6.5M  
V
3.3V  
CORE  
DD  
1M  
DP  
IN1  
IN2  
TH  
402k  
150k  
0.01µF  
1M  
MAX1808  
IN3  
IN4  
682k  
150k  
ON  
IN5  
GND  
121k  
150k  
150k  
150k  
261k  
150k  
THRESHOLDS: 1) 3.63V  
2) 5.5V  
3) 1.85V  
4) 2.0V  
5) 2.75V  
_______________________________________________________________________________________  
9
Micropower Adjustable Overvoltage  
Protection Controllers  
Package Information  
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.  
10 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600  
© 2000 Maxim Integrated Products  
Printed USA  
is a registered trademark of Maxim Integrated Products.  

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