MAX8934BETI+ [MAXIM]
Dual-Input Linear Chargers, Smart Power Selector with Advanced Battery Temperature Monitoring; 双输入线性充电器，智能电源选择器，提供高级电池温度监测
| 型号： | MAX8934BETI+ |
| 厂家： | 
MAXIM INTEGRATED PRODUCTS |
| 描述： | Dual-Input Linear Chargers, Smart Power Selector with Advanced Battery Temperature Monitoring |
| 文件： | 总31页 (文件大小：2669K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
Ordering Information
PART
MAX8934AETI+
TEMP RANGE
PIN-PACKAGE
-40NC to +85NC
28 Thin QFN-EP*
+Denotes a lead(Pb)-free/RoHS-compliant package.
*EP = Exposed pad.
Ordering Information continued and Selector Guide appears
at end of data sheet.
Typical Operating Circuit
LDO
3.3V ALWAYS-ON
LINEAR
REGULATOR
SYS
AC
ADAPTER
Q1
DC
CHARGE
CURRENT
LOAD
CURRENT
SYSTEM
LOAD
Q3
CHARGE
AND
SYS LOAD
SWITCH
USB Q2
BATT
GND
USB
BATTERY
MAX8934A−
MAX8934E
*Protected by U.S.Patent #6,507,172.
Smart Power Selector is a trademark of Maxim Integrated
Products, Inc.
Dual-Input Linear Chargers, Smart Power Selector
with Advanced Battery Temperature Monitoring
ABSOLUTE MAXIMUM RATINGS
DC, PEN1 to GND.................................................-0.3V to +16V
USB to GND ............................................................-0.3V to +9V
BATT Continuous Current (total in two pins).................2.4A
LDO Continuous Current.............................................50mA
RMS
RMS
V to GND ...............................................................-0.3V to +4V
L
LDO Short-Circuit Duration .........................................
Continuous
LDO to GND......... -0.3V to the lower of +4V and (V
THMEN, THMSW to GND..................... -0.3V to +(V
+ 0.3V)
+ 0.3V)
+ 0.3V)
Continuous Power Dissipation (T = +70NC)
Single-Layer Board
(derate 20.8mW/NC above +70NC)......................1666.7mW
Multilayer Board
SYS
LDO
A
THM to GND.......................................-0.3V to (V
THMSW
PSET, ISET, CT to GND............................... -0.3V to (V + 0.3V)
L
BATT, SYS, CEN, CHG, OT, DOK,
UOK, FLT, DONE, USUS, PEN2 to GND.............-0.3V to +6V
EP (Exposed Pad) to GND...................................-0.3V to +0.3V
DC Continuous Current (total in two pins) ....................2.4A
SYS Continuous Current (total in two pins)...................2.4A
USB Continuous Current (total in two pins) ..................2.0A
(derate 28.6mW/NC above +70NC)......................2285.7mW
Operating Temperature Range.......................... -40NC to +85NC
Junction Temperature ...................................... -40NC to +125NC
Storage Temperature ....................................... -65NC to +150NC
Lead Temperature (soldering, 10s) ................................+300NC
Soldering Temperature (reflow) ......................................+260NC
RMS
RMS
RMS
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
DC
= V
= V
= 5V, CEN = USUS = THMEN = GND, V
= 4V, V
= 1.65V, USB, THMSW, CHG, DONE, OT, DOK,
PEN1
PEN2
BATT
THM
UOK, FLT are unconnected, C = 0.068FF, T = -40NC to +85NC, unless otherwise noted. Typical values are at T = +25NC.) (Note 1)
CT
A
A
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
DC-to-SYS PREREGULATOR
DC Operating Voltage Range
DC Withstand Voltage
4.1
6.6
14
V
V
V
V
V
= V
= 0V
BATT
SYS
DC Undervoltage Threshold
DC Overvoltage Threshold
When V
When V
goes low, V
rising, 500mV hysteresis
3.95
6.8
4.0
6.9
1
4.05
7.0
2
DOK
DOK
BATT
BATT
DC
goes high, V
rising, 360mV hysteresis
DC
I
I
= I
= I
= 0mA, V
= 0mA, V
= 0V
SYS
SYS
CEN
CEN
DC Operating Supply Current
mA
= 5V
0.8
195
0.2
1.5
340
0.35
DC Suspend Current
V
DC
= V
= V
= 5V, V = 0V
PEN1
FA
I
CEN
USUS
DC-to-SYS On-Resistance
I
= 400mA, V
= 5V
CEN
SYS
When SYS regulation and charging stops, V
150mV hysteresis
falling,
DC
DC to BATT Dropout Voltage
DC Current Limit
10
50
90
mV
mA
R
R
R
= 1.5kI
= 3kI
1800
900
2000
1000
475
2200
1100
500
PSET
PSET
PSET
PEN1
V
= 6V, V
= +25NC
= 5V,
DC
SYS
T
A
= 6.3kI
450
(MAX8934A);
= 5V, V
V
DC
= 4V,
SYS
V
= 0V, V
= 5V
PEN2
450
80
475
95
500
100
T
= +25NC
A
(500mA USB mode)
(MAX8934B–
MAX8934E)
V
= V = 0V
PEN1
PEN2
(100mA USB mode)
PSET Resistance Range
SYS Regulation Voltage
1.5
5.2
6.3
5.4
4.4
kI
MAX8934A
5.3
4.35
1.5
V
= 6V, I
= 1mA
= 5V
DC
SYS
V
to 1.75A, V
CEN
MAX8934B–MAX8934E
4.29
Connecting DC with USB not present
Connecting DC with USB present
ms
Input Current Soft-Start Time
Thermal-Limit Temperature
50
Fs
Die temperature at when the charging current and input
current limits are reduced
100
NC
2
______________________________________________________________________________________
Dual-Input Linear Chargers, Smart Power Selector
with Advanced Battery Temperature Monitoring
ELECTRICAL CHARACTERISTICS (continued)
(V
DC
= V
= V
= 5V, CEN = USUS = THMEN = GND, V
= 4V, V
= 1.65V, USB, THMSW, CHG, DONE, OT, DOK,
PEN1
PEN2
BATT
THM
UOK, FLT are unconnected, C = 0.068FF, T = -40NC to +85NC, unless otherwise noted. Typical values are at T = +25NC.) (Note 1)
CT
A
A
PARAMETER
Thermal-Limit Gain
V Voltage
CONDITIONS
reduction with die temperature (above +100NC)
MIN
TYP
5
MAX
UNITS
%/C
V
I
I
SYS
= 0 to 5mA, USB = unconnected
VL
3
3.3
3.6
L
USB-TO-SYS PREREGULATOR
USB Operating Voltage Range
USB Withstand Voltage
4.1
6.6
8
V
V
V
V
V
= V
= 0V
BATT
SYS
USB Undervoltage Threshold
USB Overvoltage Threshold
When V
When V
goes low, V
rising, 500mV hysteresis
3.95
6.8
4.0
6.9
1
4.05
7.0
2
UOK
UOK
BATT
BATT
USB
goes high, V
rising, 360mV hysteresis
USB
I
I
= I
= I
= 0mA, V
= 0mA, V
= V
= 0V
SYS
SYS
CEN
CEN
PEN2
USB Operating Supply Current
mA
= 5V, V
= 0V
0.9
190
0.22
1.5
340
0.33
PEN2
USB Suspend Current
DC = unconnected, V
= V
= V = 5V
USUS
FA
I
USB
CEN
USB to SYS On-Resistance
DC unconnected, V
= V
= 5V, I
= 400mA
USB
CEN
SYS
When SYS regulation and charging stops, V
150mV hysteresis
falling,
USB
USB-to-BATT Dropout Voltage
10
50
90
mV
mA
MAX8934D only,
1350
1500
1650
USB Current Limit
(See Tables 2a and 2b for Input
Source Control)
R
= 2kI
PSET
PEN1
PEN1
DC unconnected,
= 5V, T = +25NC
V
USB
A
V
V
= 0V, V
= 5V
450
80
475
95
500
100
PEN2
= V
= 0V
PEN2
MAX8934A
5.2
5.3
5.4
4.4
DC unconnected, V
USB
= 6V, V
= 5V, I
=
PEN2
SYS
MAX8934B/MAX8934C/
MAX8934E
4.29
4.35
1mA to 400mA, V
= 5V
CEN
SYS Regulation Voltage
V
DC unconnected, V
USB
= 6V, V
= 5V, I
=
MAX8934D
4.29
4.35
4.4
PEN2
SYS
1mA to 1.2A, V
= 5V
CEN
Input Limiter Soft-Start Time
Thermal-Limit Temperature
Thermal-Limit Gain
Input current ramp time
50
Fs
NC
Die temperature at when the charging current and input
current limits are reduced
100
I
reduction with die temperature (above +100NC)
5
%/NC
SYS
V Voltage
L
DC unconnected, V
= 5V, I = 0 to 5mA
3
3.3
3.6
V
USB
USB
VL
LDO LINEAR REGULATOR
LDO Output Voltage
DC unconnected, V
= 5V, I
= 0mA
= 0mA
3.234
3.234
3.234
3.3
3.3
3.366
3.366
3.366
LDO
V
DC
= 5V, USB unconnected, I
V
LDO
DC and USB unconnected, V
= 4V, I
= 0mA
3.3
BATT
LDO
LDO Load Regulation
I
= 0 to 30mA
0.003
%/mA
LDO
_______________________________________________________________________________________
3
Dual-Input Linear Chargers, Smart Power Selector
with Advanced Battery Temperature Monitoring
ELECTRICAL CHARACTERISTICS (continued)
(V
DC
= V
= V
= 5V, CEN = USUS = THMEN = GND, V
= 4V, V
= 1.65V, USB, THMSW, CHG, DONE, OT, DOK,
PEN1
PEN2
BATT
THM
UOK, FLT are unconnected, C = 0.068FF, T = -40NC to +85NC, unless otherwise noted. Typical values are at T = +25NC.) (Note 1)
CT
A
A
PARAMETER
BATTERY CHARGER
CONDITIONS
MIN
TYP
MAX
UNITS
I
BATT-to-SYS On-Resistance
V
V
= 0V, V
= 4.2V, I = 1A
0.04
75
0.08
105
DC
BATT
SYS
BATT-to-SYS Reverse
Regulation Voltage
= V
= 0V, I = 200mA
SYS
50
mV
PEN1
PEN2
T
V
= +25NC, V
THM_T3
< V
<
A
THM_T1
THM
4.175
4.158
4.05
4.2
4.2
4.225
4.242
4.1
T
V
= 0NC to +85NC, V
<
A
THM_T1
< V
THM_T3
THM
BATT Regulation Voltage—Safety
Region 1 (MAX8934A)
I
= 0mA
V
BATT
T
V
= +25NC, V
< V
<
A
THM_T3
THM
4.075
4.075
4.2
THM_T4
T
V
= 0NC to +85NC, V
<
A
THM_T3
4.034
4.175
4.158
4.1
< V
THM_T4
THM
T
V
= +25NC, V
< V
<
A
THM_T2
THM
4.225
4.242
THM_T3
T
V
= 0NC to +85NC, V
<
A
THM_T2
4.2
< V
THM_T3
THM
BATT Regulation Voltage—Safety
Region 2
T
V
V
= +25NC, V
< V
< V <
THM
<
A
THM_T1
THM
I
= 0mA
V
BATT
or V
4.05
4.075
4.1
THM_T2
THM_T4
THM_T3
T
V
V
= 0NC to +85NC, V
<
<
A
THM_T1
< V
< V
or V
4.034
-145
4.075
-104
4.1
-65
THM
THM
THM_T2
THM_T4
THM_T3
Change in V
from DONE to fast-
charge restart
BATT
V
< V
< V
THM_T1
THM
THM_T3
BATT Recharge Threshold—
Safety Region 1 (MAX8934A)
mV
V
V
< V
< V
< V
< V
-120
-145
-80
-40
-65
THM_T3
THM
THM_T4
-104
THM_T2
THM
THM_T3
Change in V
BATT
BATT Recharge Threshold—
Safety Region 2
from DONE to fast-
charge restart
mV
A
V
V
< V
< V
< V
< V
or
THM_T1
THM
THM_T2
-120
0.3
-80
-40
1.5
THM_T3
THM
THM_T4
BATT Fast-Charge
Current Range
R
ISET
= 10kIto 2kI
4
______________________________________________________________________________________
Dual-Input Linear Chargers, Smart Power Selector
with Advanced Battery Temperature Monitoring
ELECTRICAL CHARACTERISTICS (continued)
(V
DC
= V
= V
= 5V, CEN = USUS = THMEN = GND, V
= 4V, V
= 1.65V, USB, THMSW, CHG, DONE, OT, DOK,
PEN1
PEN2
BATT
THM
UOK, FLT are unconnected, C = 0.068FF, T = -40NC to +85NC, unless otherwise noted. Typical values are at T = +25NC.) (Note 1)
CT
A
A
PARAMETER
CONDITIONS
MIN
1350
675
TYP
1500
750
MAX
1650
825
UNITS
R
ISET
R
ISET
R
ISET
R
ISET
= 2kI
= 4kI
V
V
< V
region 1) or V
< V
= 5.5V,
SYS
= 10kI
270
300
330
< V
THM_T2
THM
= 2kI, V
= 2.5V
= 2.5V
BATT
BATT
130
50
150
75
170
100
(safety
THM_T4
(prequal)
THM_T1
< V
THM_T4
R
ISET
= 4kI, V
THM
(prequal)
(safety region 2)
R
= 10kI, V
= 2.5V
BATT
ISET
30
(prequal)
BATT Charge Current Accuracy
mA
R
R
R
R
= 2kI
675
337.5
130
750
375
150
825
412.5
170
ISET
ISET
ISET
ISET
= 4kI
= 10kI
V
V
< V
= 5.5V,
SYS
= 2kI, V
= 2.5V
= 2.5V
BATT
BATT
100
50
150
75
30
1
200
100
< V
THM_T1
THM
(prequal)
(safety
THM_T2
R
ISET
= 4kI, V
region 1)
(prequal)
R
ISET
= 10kI, V
= 2.5V
BATT
(prequal)
R
= 4kI, I
= 500mA (V
THM_T2
= 1.5V at full
ISET
ISET
BATT
ISET Output Voltage
0.9
2.9
1.1
V
charge current) V
< V
< V
THM THM_T4
Charger Soft-Start Time
BATT Prequal Threshold
Charge-current ramp time
1.5
3
ms
V
V
rising, 180mV hysteresis
3.1
12
BATT
No DC or USB power
connected, THMEN = low,
5
V
CEN
= 5V
No DC or USB power
connected, THMEN = high,
V
= 4.2V,
= 0
BATT
BATT Input Current
FA
12
25
2
I
I
LDO
V
= 5V
CEN
DC or USB power connected,
= 5V
0.003
V
CEN
DONE Threshold as a
Percentage of Fast-Charge
Current
decreasing
10
%
BATT
_______________________________________________________________________________________
5
Dual-Input Linear Chargers, Smart Power Selector
with Advanced Battery Temperature Monitoring
ELECTRICAL CHARACTERISTICS (continued)
(V
DC
= V
= V
= 5V, CEN = USUS = THMEN = GND, V
= 4V, V
= 1.65V, USB, THMSW, CHG, DONE, OT, DOK,
PEN1
PEN2
BATT
THM
UOK, FLT are unconnected, C = 0.068FF, T = -40NC to +85NC, unless otherwise noted. Typical values are at T = +25NC.) (Note 1)
CT
A
A
PARAMETER
Maximum Prequal Time
Maximum Fast-Charge Time
CONDITIONS
MIN
TYP
30
MAX
UNITS
min
min
s
From CEN falling to end of prequal charge, V
From CEN falling to FLT falling
MAX8934A/MAX8934C/MAX8934E
MAX8934B/MAX8934D
= 2.5V
BATT
300
15
Maximum Top-Off Time
Timer Accuracy
60
min
%
-20
+20
Percentage of fast-charge current below where the timer
clock operates at half-speed
Timer Extend Threshold
50
20
%
%
Percentage of fast-charge current below where timer
clock pauses
Timer Suspend Threshold
THERMISTOR MONITOR (Beta = 3477) (Note 2)
-2.2
73.9
8
0
+2.4
75.1
12
NC
THM Cold No-Charge Threshold
(T1)
I
= 0A, when charging is suspended, 2NC hysteresis
CHG
% of
THMSW
74.4
10
NC
I
reduced (safety region 1 only), V
CHG
BATT_REG
THM Cold Threshold (T2)
% of
THMSW
reduced (safety region 2 only), 2NC hysteresis
64.5
42.8
32.1
57
65
65.5
47.5
32.8
63.5
23
45
NC
THM Hot Threshold (T3)
V
reduced (safety region 1), 2.5NC hysteresis
BATT_REG
% of
THMSW
32.4
60
NC
THM Hot No-Charge Threshold
(T4)
I
= 0mA, when charging is suspended, 3NC
CHG
% of
THMSW
hysteresis
22.4
71
22.7
75
80
NC
THM Hot Overtemperature
OT asserts low, 5NC hysteresis
% of
THMSW
Threshold (T )
OT
15.5
15.8
16
THERMISTOR MONITOR (Beta = 3964) (Note 3)
-2.1
76.4
8.2
0
77.2
10
+2.4
77.9
12
NC
THM Cold No-Charge Threshold
(T1)
I
= 0A, when charging is suspended, 2NC hysteresis
CHG
% of
THMSW
NC
I
reduced (safety region 1 only), V
CHG
BATT_REG
THM Cold Threshold (T2)
% of
THMSW
reduced (safety region 2), 2NC hysteresis
66.2
67
67.6
6
______________________________________________________________________________________
Dual-Input Linear Chargers, Smart Power Selector
with Advanced Battery Temperature Monitoring
ELECTRICAL CHARACTERISTICS (continued)
(V
DC
= V
= V
= 5V, CEN = USUS = THMEN = GND, V
= 4V, V
= 1.65V, USB, THMSW, CHG, DONE, OT, DOK,
PEN1
PEN2
BATT
THM
UOK, FLT are unconnected, C = 0.068FF, T = -40NC to +85NC, unless otherwise noted. Typical values are at T = +25NC.) (Note 1)
CT
A
A
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
42.8
45
47.5
NC
THM Hot Threshold (T3)
V
reduced, safety region 1, 2.5NC hysteresis
BATT_REG
% of
THMSW
29.8
57
30
60
30.6
63.5
20.1
80
NC
THM Hot No-Charge Threshold
(T4)
I
= 0mA, when charging is suspended, 3NC
CHG
% of
THMSW
hysteresis
19.5
71
19.8
75
NC
THM Hot Discharge Threshold
OT asserts low, 5NC hysteresis
% of
THMSW
(T
OT
)
12.6
-1
12.9
13.1
+1
T
A
T
A
T
A
T
A
= +25NC
= +85NC
= +25NC
= +85NC
+0.001
0.01
THM Input leakage
THM = GND or LDO
THMSW = GND
Sourcing 1mA
FA
FA
V
-0.2
+0.001
0.01
+1
THMSW Output Leakage
THMSW Output Voltage High
V
LDO
0.05
-
LOGIC I/O: PEN1, PEN2, CHG, FLT, DONE, DOK, UOK, USUS, THMEN)
High level
1.3
V
Logic-Input Thresholds
Low level
0.4
1
Hysteresis
50
0.001
0.01
25
mV
FA
mV
FA
T
T
= +25NC
= +85NC
A
Logic-Input Leakage Current
Logic-Low Output Voltage
V
IN
= 0 to 5.5V
A
Sinking 1mA
= 5.5V
100
1
T
T
= +25NC
= +85NC
0.001
0.01
Logic-High Output Leakage
Current
A
V
OUT
A
Note 1: Limits are 100% production tested at T = +25NC. Limits over the operating temperature range are guaranteed by design.
A
Note 2: NC includes external NTC thermistor error. % of THMSW excludes thermistor beta error and external pullup error. NTC
thermistor assumed to be 10kI nominal, part number Vishay NTHS0603N02N1002FF, external pullup resistor = 10kI.
Note 3: NC includes external NTC thermistor error. % of THMSW excludes thermistor beta error and external pullup error. NTC
thermistor assumed to be 100kI Q1% nominal, part number Vishay NTHS0603N01N1003FF, external pullup resistor =
100kI Q1%.
_______________________________________________________________________________________
7
Dual-Input Linear Chargers, Smart Power Selector
with Advanced Battery Temperature Monitoring
Typical Operating Characteristics
(MAX8934A, T = +25NC, circuit of Figure 2, V
= 6V, V
= 3.6V, thermistor Beta = 3964, unless otherwise noted. Negative bat-
A
DC
BATT
tery current indicates charging.)
USB OPERATING SUPPLY CURRENT
vs. USB VOLTAGE (CHARGER ENABLED)
1200
USB OPERATING SUPPLY CURRENT
vs. USB VOLTAGE (CHARGER DISABLED)
USB SUSPEND CURRENT
vs. USB VOLTAGE
900
250
200
150
100
50
V
V
= 4.2V,
= 0V
V
= 4.2V,
USUS = 1
V
V
= 4.2V,
= 0V
BATT
USUS
BATT
BATT
USUS
800
700
600
500
400
300
200
100
0
1000
800
600
400
200
0
CEN = 1
= 0A
CHARGER IN
DONE MODE
I
SYS
PEN1 = X, PEN2 = 1
I
= 0A
SYS
V
V
RISING
FALLING
USB
USB
V
USB
V
USB
RISING
FALLING
ENTERING OVLO
ENTERING OVLO
0
0
1
2
3
4
5
6
7
8
0
1
2
3
4
5
6
7
8
0
1
2
3
4
5
6
7
8
USB VOLTAGE (V)
USB VOLTAGE (V)
USB VOLTAGE (V)
BATTERY INPUT CURRENT
vs. BATTERY VOLTAGE
(USB DISCONNECTED)
BATTERY INPUT CURRENT
vs. TEMPERATURE
CHARGE CURRENT vs.
BATTERY VOLTAGE (100mA USB)
5.0
4.9
4.8
4.7
4.6
4.5
4.4
4.3
4.2
4.1
4.0
14
12
10
8
100
90
80
70
60
50
40
30
20
10
0
V
= 4V, THMEN = 0, I = 0
LDO
BATT
USB AND DC UNCONNECTED
V
= 5V
USB
THMEN = 1
PEN1 = X, PEN2 = 0
V
BATT
V
BATT
RISING
FALLING
6
4
THMEN = 0
2
0
-40
-15
10
35
60
85
0
1
2
3
4
5
0
1
2
3
4
5
TEMPERATURE (°C)
BATTERY VOLTAGE (V)
BATTERY VOLTAGE (V)
CHARGE CURRENT vs.
BATTERY VOLTAGE (500mA USB)
CHARGE CURRENT vs.
BATTERY VOLTAGE (1A DC)
500
450
400
350
300
250
200
150
100
50
1200
V
= 5V
USB
V
= 5V
DC
PEN1 = X, PEN2 = 1
1000
800
600
400
200
0
PEN1 = 1, PEN2 = X
V
BATT
V
BATT
RISING
FALLING
V
BATT
V
BATT
RISING
FALLING
0
0
1
2
3
4
5
0
1
2
3
4
5
BATTERY VOLTAGE (V)
BATTERY VOLTAGE (V)
8
______________________________________________________________________________________
Dual-Input Linear Chargers, Smart Power Selector
with Advanced Battery Temperature Monitoring
Typical Operating Characteristics (continued)
(MAX8934A, T = +25NC, circuit of Figure 2, V
= 6V, V = 3.6V, thermistor Beta = 3964, unless otherwise noted. Negative bat-
BATT
A
DC
tery current indicates charging.)
NORMALIZED CHARGE CURRENT
vs. AMBIENT TEMPERATURE
(LOW IC POWER DISSIPATION)
BATTERY REGULATION VOLTAGE
vs. TEMPERATURE
1.0100
1.0075
1.0050
1.0025
1.0000
0.9975
0.9950
0.9925
0.9900
4.220
V
= 5V, V
= 4V
BATT
USB
4.215
4.210
4.205
4.200
4.195
4.190
4.185
4.180
4.175
4.170
-40
-15
10
35
60
85
-40
-15
10
35
60
85
AMBIENT TEMPERATURE (°C)
BATTERY VOLTAGE (V)
SYS OUTPUT VOLTAGE
vs. USB VOLTAGE
SYS OUTPUT VOLTAGE
vs. DC VOLTAGE
5.4
5.2
5.0
4.8
4.6
4.4
4.2
4.0
5.4
5.2
5.0
4.8
4.6
4.4
4.2
4.0
V
= 4.0V
V
= 4.0V
BATT
BATT
NO SYS LOAD
NO SYS LOAD
MAX8934A
MAX8934A
MAX8934B–
MAX8934E
MAX8934B–
MAX8934E
0
1
2
3
4
5
6
7
8
0
2
4
6
8
10
12
14
USB VOLTAGE (V)
DC VOLTAGE (V)
SYS OUTPUT VOLTAGE vs. SYS OUTPUT
CURRENT (USB AND DC DISCONNECTED)
SYS OUTPUT VOLTAGE
vs. SYS OUTPUT CURRENT (DC)
4.5
4.4
4.3
4.2
4.1
4.0
3.9
3.8
3.7
3.6
5.5
5.1
4.7
4.3
3.9
3.5
V
= 4.0V
BATT
V
= 6V
DC
THE SLOPE OF THIS LINE
SHOWS THAT THE BATT-TO-SYS
RESISTANCE IS 40mI.
MAX8934A
V
= 5V
DC
V
= 6V
DC
MAX8934B–
MAX8934E
V
= 5V
DC
V
= 4V,
BATT
PEN1 = 1, PEN2 = X
CEN = 1
0
0.5
1.0
1.5
2.0
0
0.5
1.0
1.5
2.0
2.5
3.0
SYS OUTPUT CURRENT (A)
SYS OUTPUT CURRENT (A)
_______________________________________________________________________________________
9
Dual-Input Linear Chargers, Smart Power Selector
with Advanced Battery Temperature Monitoring
Typical Operating Characteristics (continued)
(MAX8934A, T = +25NC, circuit of Figure 2, V
= 6V, V = 3.6V, thermistor Beta = 3964, unless otherwise noted. Negative bat-
BATT
A
DC
3.0
14
tery current indicates charging.)
SYS OUTPUT VOLTAGE vs.
SYS OUTPUT CURRENT (USB)
5.5
SYS OUTPUT VOLTAGE vs.
SYS OUTPUT CURRENT (USB)
5.5
V
V
= 4.0V,
= 5.0V
BATT
USB
5.3
5.1
4.9
4.7
4.5
4.3
4.1
3.9
3.7
3.5
V
V
= 4.0V,
= 5.0V
5.3
5.1
4.9
4.7
4.5
4.3
4.1
3.9
3.7
3.5
BATT
USB
CEN = 1
CEN = 1
0.14A, MAX8934B/MAX8934C/
MAX8934D PEN1 = 0, PEN2 = 0
0.5A, MAX8934B/MAX8934C/
MAX8934D PEN1 = 0, PEN2 = 0
0.5A, MAX8934A,
PEN1 = 0, PEN2 = 1
1.5A, MAX8934D
PEN1 = 1, PEN2 = 1
0.1A, MAX8934A, PEN1 = 0, PEN2 = 0
0
0.5
1.0
1.5
2.0
2.5
0
0.5
1.0
1.5
2.0
2.5
3.0
SYS OUTPUT CURRENT (A)
SYS OUTPUT CURRENT (A)
V OUTPUT VOLTAGE vs.
L
CHARGE PROFILE—820mAh BATTERY
DC VOLTAGE
USB INPUT—500mA CHARGE
MAX8934A toc17
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0
500
450
400
350
300
250
200
150
100
50
4.5
4.0
3.5
3.0
2.5
2.0
V
BATT
I
BATT
I
VL
= 5mA
I
= 0mA
6
VL
0
0
2
4
8
10
12
0
20
40
60
80 100 120 140
DC VOLTAGE (V)
TIME (min)
CHARGE PROFILE—820mAh BATTERY
ADAPTER INPUT—1A CHARGE
DC CONNECT WITH USB
CONNECTED (R = 22I)
SYS
MAX8934A/B/C toc19
1.2
1.0
0.8
0.6
0.4
0.2
0
4.5
4.0
3.5
3.0
2.5
2.0
1.5
4.2V
CHARGING
5.3V
C
V
SYS
5V/div
1A/div
CHARGING
SYS
C
DC
V
1.24A
BATT
I
DC
0A
500mA/div
1A/div
I
USB
475mA
I
BATT
BATTERY CHARGER SOFT-START
0A
-190mA
I
BATT
-1A
0
10 20 30 40 50 60 70 80
TIME (min)
400Fs/div
10 _____________________________________________________________________________________
Dual-Input Linear Chargers, Smart Power Selector
with Advanced Battery Temperature Monitoring
Typical Operating Characteristics (continued)
(MAX8934A, T = +25NC, circuit of Figure 2, V
= 6V, V = 3.6V, thermistor Beta = 3964, unless otherwise noted. Negative bat-
BATT
A
DC
tery current indicates charging.)
DC CONNECT WITH NO
DC DISCONNECT WITH NO
USB (R
= 22I)
USB (R
= 22I)
SYS
SYS
MAX8934A/B/C toc20
MAX8934A/B/C toc21
V
V
BATT
BATT
5V/div
5V/div
5V/div
3.6V
3.5V
3.6V
V
V
SYS
SYS
5V/div
5V
3.5V
1.2A
1A
1A/div
I
DC
C
CHARGING
1A/div
DC
I
DC
0A
0A
160mA
160mA
0mA
I
BATT
I
BATT
1A/div
-1A
1A/div
BATTERY CHARGER
SOFT-START
-820mA
-I
BATT
= CHARGING
400Fs/div
400Fs/div
USB CONNECT WITH NO
USB DISCONNECT WITH NO
DC (R
= 22I)
DC (R
= 22I)
SYS
SYS
MAX8934A/B/C toc22
MAX8934A/B/C toc23
V
USB
USB
5V/div
5V/div
V
USB
USB
5V
C
CHARGING
5V
SYS
500mA/div
3V
500mA/div
I
I
475mA
4.2V
475mA
0A
0mA
C
CHARGING
USB
5V
V
V
5V/div
SYS
3.6V
3.9V
V
V
3.6V
SYS
5V/div
5V/div
5V/div
UOK
CHG
3.3V
3.3V
UOK
CHG
5V/div
5V/div
3.3V
V
V
I
3.3V
I
BATT
-260mA
+160mA
-260mA
500mA/div
BATT
+160mA
500mA/div
BATTERY
CHARGER SOFT-START
200Fs/div
200Fs/div
USB RESUME (R
= 22I)
MAX8934A/B/C toc25
USB SUSPEND (R
= 22I)
MAX8934A/B/C toc24
SYS
SYS
5V/div
0V
0V
V
5V/div
USUS
3V
V
USUS
3V
I
USB
500mA/div
5V/div
475mA
4.2V
475mA
4.2V
I
0A
500mA/div
5V/div
USB
0A
4.6V
3.3V
3.2V
V
SYS
V
SYS
5V/div
5V/div
3.3V
0A
V
3.3V
0A
V
CHG
CHG
3.3V
I
BATT
500mA/div
I
500mA/div
BATT
BATTERY
CHARGER SOFT-START
V
= 5V
V
USB
= 5V
USB
200Fs/div
200Fs/div
______________________________________________________________________________________ 11
Dual-Input Linear Chargers, Smart Power Selector
with Advanced Battery Temperature Monitoring
Typical Operating Characteristics (continued)
(MAX8934A, T = +25NC, circuit of Figure 2, V
= 6V, V = 3.6V, thermistor Beta = 3964, unless otherwise noted. Negative bat-
BATT
A
DC
tery current indicates charging.)
LDO OUTPUT VOLTAGE vs. LDO OUTPUT
CURRENT (USB DISCONNECTED)
LDO STARTUP WAVEFORMS
MAX8934A/B/C toc27
3.35
3.30
3.25
3.20
3.15
3.10
3.05
3.00
2.95
I
= 0
V
= 4.0V
LDO
BATT
3.6V
3.3V
2V/div
2V/div
V
BATT
DC UNCONNECTED
= 5.0V
V
LDO
V
DC
50mA/div
I
BATT
400Fs/div
0
25
50
75 100 125 150 175
LDO OUTPUT CURRENT (mA)
LDO OUTPUT VOLTAGE vs.
BATTERY VOLTAGE
ALWAYS-ON LDO POWER-SUPPLY
REJECTION RATIO vs. FREQUENCY
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0
0
V
= 3.6V
SYS
-5
-10
-15
-20
-25
-30
-35
-40
-45
-50
I
= 10mA
LDO
RESISTIVE LOAD
V
FALLING
RISING
BATT
V
BATT
0
0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0
BATTERY VOLTAGE (V)
0.1
1
10
100
FREQUENCY (kHz)
LDO NOISE DENSITY
vs. FREQUENCY
THM NORMAL TO THM COLD
(< T2) TRANSITION
MAX8934A/B/C toc31
900
800
700
600
500
400
300
200
100
0
V
= 3.8V,
BATT
= 10mA
I
LDO
500mV/div
2V/div
V
THM
RESISTIVE LOAD
2.2V
3.6V
V
BATT
1A
I
BATT
500mA
500mA/div
0.01
0.1
1
10
100 1000 10,000
10ms/div
FREQUENCY (kHz)
12 _____________________________________________________________________________________
Dual-Input Linear Chargers, Smart Power Selector
with Advanced Battery Temperature Monitoring
Typical Operating Characteristics (continued)
(MAX8934A, T = +25NC, circuit of Figure 2, V
= 6V, V = 3.6V, thermistor Beta = 3964, unless otherwise noted. Negative bat-
BATT
A
DC
tery current indicates charging.)
THM NORMAL TO THM HOT
(> T3) TRANSITION
THM NORMAL TO THM HOT NO
CHARGE (> T4) TRANSITION
MAX8934A/B/C toc32
MAX8934A/B/C toc33
0.65V
500mV/div
500mV/div
2V/div
V
V
THM
THM
1.0V
4.2V
4.075V
4.2V
V
I
V
I
0V
BATT
BATT
4.075V
200mV/div
500mA/div
100mA
BATT
940mA
BATT
100mA/div
0mA
HP6060B ELECTRONIC LOAD
SET TO CC MODE
HP6060B ELECTRONIC
LOAD SET TO CC MODE
10ms/div
20ms/div
THM NORMAL TO THM HOT
THM NORMAL TO THM COLD NO
CHARGE (< T1) TRANSITION
THRESHOLD DISCHARGE T
OT
MAX8934A/B/C toc35
MAX8934A toc34
V
THM
2V/div
2V/div
500mV/div
2V/div
V
THM
BATT
BATT
4.025V
2.54V
V
OT
3V
2.2V
3.6V
V
I
V
2V/div
2V/div
BATT
1A
3.6V
3.6V
500mA
500mA/div
V
SYS
0mA
10ms/div
4ms/div
______________________________________________________________________________________ 13
Dual-Input Linear Chargers, Smart Power Selector
with Advanced Battery Temperature Monitoring
Pin Description
PIN
NAME
FUNCTION
Charge Complete Output. The DONE active-low, open-drain output pulls low when the charger enters
the DONE state. The charger current = 0mA when DONE is low. See Figure 8.
1
DONE
DC Power Input. DC is capable of delivering up to 2A to SYS. DC supports both AC adapter and USB
inputs. The DC current limit is set with PEN1, PEN2, and R
connected together externally. Connect a 10FF ceramic capacitor from DC to GND. The DC inputs should
. See Table 2. Both DC pins must be
PSET
2, 3
DC
be grounded if not used.
Active-Low Charger Enable Input. Connect CEN to GND or drive low with a logic signal to enable
battery charging when a valid source is connected at DC or USB. Drive high with a logic signal to
disable battery charging.
4
5
CEN
Input Limit Control 1. See Table 2a for complete information (MAX8934A/MAX8934B/MAX8934C/
MAX8934E).
PEN1
Input Limit Control 1. See Table 2b for complete information (MAX8934D).
Input Limit Control 2. See Table 2a for complete information (MAX8934A/MAX8934B/MAX8934C/
MAX8934E).
6
7
8
PEN2
PSET
Input Limit Control 2. See Table 2b for complete information (MAX8934D).
DC Input Current-Limit Setting. Connect a resistor from PSET to GND to program the DC current limit up
to 2A (3000/R ).
PSET
Internal Logic LDO Output Bypass Pin. Provides 3.3V when DC or USB is present. Connect a 0.1FF
ceramic capacitor from V to GND. V powers the internal circuitry and provides up to 5mA to an
V
L
L
L
external load.
9, 13
10
GND
CT
Ground. Both GND pins must be connected together externally.
Charge Timer Program Input. A capacitor from CT to GND sets the maximum prequal and fast-charge
timers. Connect CT to GND to disable the timer.
Charge Current-Limit Setting. A resistor (R ) from ISET to GND programs the fast-charge charge
ISET
11
12
ISET
current up to 1.5A (3000/R
current.
). The prequal charge current is 10% of the set fast-charge charge
ISET
USB Suspend Digital Input. As shown in Table 2a, driving USUS high suspends the DC or USB inputs if
they are configured as a USB power input (MAX8934A/MAX8934B/MAX8934C/MAX8934E).
USUS
USB Suspend Digital Input. As shown in Table 2b, driving USUS high suspends the DC or USB inputs if
they are configured as a USB power input (MAX8934D).
Thermistor Input. Connect a negative temperature coefficient (NTC) thermistor with good thermal
contact with the battery from THM to GND. Use a thermistor with Beta = 3964. Connect a resistor
of equal resistance to the thermistor resistance at +25°C from THM to THMSW so that the battery
temperature can be monitored, and the fast-charge current and/or the charge termination voltage is
automatically adjusted, in accordance with safety region 1 or safety region 2 of the JEITA specification.
14
15
THM
Thermistor Enable Input. THMEN controls THMSW by connecting the external thermistor pullup resistor
and the thermistor monitoring circuit to LDO. Drive THMEN high to enable the thermistor circuit in
discharge mode and to connect the external thermistor pullup resistor. Drive THMEN low to disconnect
the external thermistor pullup resistor and to disable the thermistor monitoring circuit to conserve
battery energy when not charging.
THMEN
14 _____________________________________________________________________________________
Dual-Input Linear Chargers, Smart Power Selector
with Advanced Battery Temperature Monitoring
Pin Description (continued)
PIN
NAME
FUNCTION
Thermistor Pullup Supply Switch. Drive THMEN high to enable the THMSW, shorting the THMSW output
to LDO. Drive THMEN low to open the THMSW switch. THMSW is always on when a valid input source
is present and the battery is being charged. When no input source is present, THMSW is controlled by
THMEN. THMSW is also active when the battery is being discharged, so that the battery temperature
can be monitored for an overtemperature condition.
16
THMSW
Always-On Linear Regulator Output. LDO is the output of an internal always-on 3.3V LDO that provides
power to external circuitry. The LDO output provides up to 30mA of current for indicator LEDs or other
loads. LDO remains active even when only a battery is present, so that the thermistor monitor circuitry
can be activated when the battery is being discharged, and other circuitry can remain powered.
Connect a 1FF ceramic capacitor from LDO to GND.
17
LDO
USB
USB Power Input. USB is capable of delivering up to 0.5A to SYS in the MAX8934A/MAX8934B/
MAX8934C/MAX8934E. The USB current limit is set with PEN2 and USUS. See Table 2a. In the
MAX8934D, USB is capable of delivering up to 1.5A to SYS. Both USB pins must be connected together
externally. Connect a 4.7FF ceramic capacitor from USB to GND.
18, 19
Battery Connection. Connect the positive terminal of a single-cell Li+ battery to BATT. The battery
charges from SYS when a valid source is present at DC or USB. BATT powers SYS when neither DC nor
USB power is present, or when the SYS load exceeds the input current limit. Both BATT pins must be
connected together externally.
20, 21
22
BATT
Charger Status Output. The CHG active-low, open-drain output pulls low when the battery is in fast
charge or prequal. Otherwise, CHG is high impedance.
CHG
System Supply Output. SYS is connected to BATT through an internal 40mIsystem load switch when
DC or USB are invalid, or when the SYS load is greater than the input current limit.
When a valid voltage is present at DC or USB, SYS is limited to 5.3V (MAX8934A) or 4.35V (MAX8934B/
23, 24
SYS
MAX8934C/MAX8934D/MAX8934E). When the system load (I ) exceeds the DC or USB current limit,
SYS
SYS is regulated to 68mV below V
and both the input and the battery service the SYS load.
BATT
Bypass SYS to GND with a 10FF ceramic capacitor. Both SYS pins must be connected together
externally.
Battery Overtemperature Flag. The OT active-low, open-drain output pulls low when THMEN is high and
the battery temperature is R+75NC.
25
26
27
28
—
OT
DOK
UOK
FLT
EP
DC Power-OK Output. The DOK active-low, open-drain output pulls low when a valid input is detected
at DC.
USB Power-OK Output. The UOK active-low, open-drain output pulls low when a valid input is detected
at USB.
Fault Output. The FLT active-low, open-drain output pulls low when the battery timer expires before
prequal or fast charge complete.
Exposed Pad. Connect the exposed pad to GND. Connecting the exposed pad does not remove the
requirement for proper ground connections to the appropriate pins.
______________________________________________________________________________________ 15
Dual-Input Linear Chargers, Smart Power Selector
with Advanced Battery Temperature Monitoring
OT
LDO
DC POWER MANAGEMENT
DC
DC
SYS
SYS
Li+ BATTERY CHARGER
AND SYS LOAD SWITCH
PWR OK
3.3V ALWAYS-ON
LOW-I LDO
Q
CHARGER
CURRENT AND
VOLTAGE
CURRENT-
LIMITED VOLTAGE
REGULATOR
DOK
ISET
CONTROL
BATT
BATT
SET INPUT
LIMIT
V
L
V LDO FOR
L
IC POWER
THERMISTOR
MONITOR
(SEE FIGURE 5)
USB POWER MANAGEMENT
T
THM
USB
UOK
THMSW
PWR OK
THMEN
CHG
CURRENT-
LIMITED VOLTAGE
REGULATOR
THERMAL
REGULATION
CHG
CHARGE
TERMINATION
AND MONITOR
DONE
SET INPUT
LIMIT
FLT
CT
CHARGE
TIMER
PEN1
INPUT AND
CHARGER
CURRENT-LIMIT
LOGIC CONTROL
PEN2
USUS
PSET
MAX8934A–
MAX8934E
CEN
GND
EP
Figure 1. Block Diagram
16 _____________________________________________________________________________________
Dual-Input Linear Chargers, Smart Power Selector
with Advanced Battery Temperature Monitoring
TO LDO
R
1MI
PU
R
PU
4x 1MI
1
CHARGE
DONE
ADAPTER
25
28
27
26
DONE
OT
FLT
OVERTEMPERATURE
MAX8934A–
MAX8934E
FAULT OUTPUT
USB PWR OK
DC PWR OK
2
3
DC
DC
UOK
DOK
C
DC
10FF
5
4
PEN1
OFF
CHARGE ON
500mA
100mA
TO
SYSTEM
LOAD
23
SYS
CEN
C
10FF
SYS
SYS 24
6
7
PEN2
PSET
1MI
LDO
22
CHARGE
INDICATOR
R
PSET
CHG
1.5kI
11
8
BATT 20
BATT 21
ISET
R
3kI
ISET
1-CELL
Li+
C
4.7FF
BATT
V
L
C
VL
0.1FF
9, 13
USB 18
USB 19
GND
1
VBUS
D-
C
CT
2
3
C
4.7FF
USB
0.068FF
10
15
16
CT
D+
THMSW
ACTIVE
4
5
ID
THMEN
GND
17
DISABLED
LDO
THMSW
THM
C
1FF
LDO
14
100kI
NTC
100kI
25C
USB SUSPEND
12
USUS
EP
Figure 2. Typical Application Circuit Using Separate DC and USB Connector
______________________________________________________________________________________ 17
Dual-Input Linear Chargers, Smart Power Selector
with Advanced Battery Temperature Monitoring
TO LDO
R
1MI
PU
R
PU
4x 1MI
5-PIN USB
CONNECTOR
CHARGE
DONE
1
2
3
25
28
27
26
DONE
DC
OT
FLT
OVERTEMPERATURE
MAX8934A–
MAX8934E
1
FAULT OUTPUT
USB PWR OK
VBUS
D-
2
3
UOK
DOK
C
10FF
DC
DC
D+
DC PWR OK
4
5
ID
GND
OFF
CHARGE ON
DC
TO
SYSTEM
LOAD
4
SYS 23
SYS 24
CEN
C
10FF
SYS
5
PEN1
1MI
USB
V
LDO
22
CHARGE
INDICATOR
500mA
6
7
CHG
PEN2
100mA
PSET
BATT 20
BATT 21
R
PSET
1-CELL
Li+
C
BATT
1.5kI
4.7FF
11
8
ISET
R
3kI
ISET
USB 18
USB 19
V
L
C
VL
0.1FF
9, 13
GND
C
CT
0.068FF
10
15
16
17
CT
LDO
THMSW
ACTIVE
C
1FF
LDO
THMEN
DISABLED
THMSW
THM
USB SUSPEND
12
USUS
14
100kI
NTC
100kI
25C
EP
Figure 3. Typical Application Circuit Using a 5-Pin USB Connector or Other DC/USB Common Connector
18 _____________________________________________________________________________________
Dual-Input Linear Chargers, Smart Power Selector
with Advanced Battery Temperature Monitoring
Table 1. External Components List for Figures 2 and 3
COMPONENT
(Figures 2 and 3)
FUNCTION
PART NUMBER
10FF ±10%, 16V X5R ceramic capacitor (0805)
Taiyo Yuden EMK212BJ106KG
C
DC
DC filter capacitor
0.1FF ±10%, 10V X5R ceramic capacitor (0402)
Taiyo Yuden LMK105BJ104KV
C
VL
V filter capacitor
L
10FF ±10%, 6.3V X5R ceramic capacitor (0805)
Taiyo Yuden JMK212BJ106KD
C
SYS output bypass capacitors
Battery bypass capacitor
Charger timing capacitor
LDO output capacitor
SYS
4.7FF ±10%, 6.3V X5R ceramic capacitor (0805)
Taiyo Yuden JMK212BJ475KD
C
BATT
0.068FF ±10%, 16V X5R ceramic capacitor (0402)
Taiyo Yuden EMK105BJ683KV
C
CT
1FF ±10%, 6.3V X5R ceramic capacitor (0402)
Taiyo Yuden JMK105BJ105KV
C
LDO
R
(x5)
Logic-output pullup resistors
Negative TC thermistor
1MI ±5% resistor
PU
THM
Vishay NTC Thermistor P/N NTHS0603N01N1003FF
100kI
R
THM pullup resistor
THMSW
R
DC input current-limit programming resistor
Fast-charge current programming resistor
1.5kI ±1% for 2A limit
PSET
R
3kI ±1% for 1A charging
ISET
input pin. If both the DC and USB sources are con-
nected, DC takes precedence.
Detailed Description
The MAX8934_ is a dual-input linear charger with
Smart Power Selector that safely charges a single Li+/
Li-Poly cell in accordance with JEITA specifications.
The MAX8934_ integrates power MOSFETs and control
circuitry to manage power flow in portable devices. See
Figure 1. The charger has two power inputs, DC and
USB. These can be separately connected to an AC
adapter output and a USB port, or the DC input could be
a single power input that connects to either an adapter
or USB. Logic inputs, PEN1 and PEN2, select the cor-
rect current limits for two-input or single-input operation.
Figure 2 is the typical application circuit using separate
DC and USB connectors. Figure 3 is the typical applica-
tion circuit using a 5-pin USB connector or another DC/
USB common connector.
In some instances, there may not be enough adapter
current or USB current to supply peak system loads. The
MAX8934_ Smart Power Selector circuitry offers flexible
power distribution from an AC adapter or USB source
to the battery and system load. The battery is charged
with any available power not used by the system load.
If a system load peak exceeds the input current limit,
supplemental current is taken from the battery. Thermal
limiting prevents overheating by reducing power drawn
from the input source.
The MAX8934_ features an overvoltage limiter at SYS. If
the DC or USB input voltage exceeds the SYS regulation
voltage, V
does not follow V
or V , but remains
USB
SYS
DC
at its regulation voltage. The MAX8934_ has numerous
other charging and power-management features that are
detailed in the following sections.
In addition to charging the battery, the MAX8934_ also
supplies power to the system through the SYS output.
The charging current is also provided from SYS so that
the set input current limit controls the total SYS current,
where total SYS current is the sum of the system load
current and the battery-charging current. SYS is pow-
ered from either the DC input pin or the USB sources
A 3.3V ultra-low quiescent current, always-on LDO pro-
vides up to 30mA for indicator LEDs and for backup
power to the system. This LDO powers the thermistor
monitor circuitry and provides bias to the external pullup
resistor for the thermistor.
*JEITA (Japan Electronics and Information Technology Industries Association) Standard, A Guide to the Safe Use of Secondary
Lithium Ion Batteries on Notebook–Type Personal Computers, April 20, 2007.
______________________________________________________________________________________ 19
Dual-Input Linear Chargers, Smart Power Selector
with Advanced Battery Temperature Monitoring
and charger loads at SYS, it performs several additional
functions to optimize use of available power.
Smart Power Selector
The MAX8934_ Smart Power Selector seamlessly distrib-
utes power among the external inputs, the battery, and
the system load (see the Typical Operating Circuit). The
basic functions performed are:
Input Voltage Limiting
If an input voltage is above the overvoltage threshold
(6.9V typ), the MAX8934_ enters overvoltage lockout
(OVLO). OVLO protects the MAX8934_ and downstream
circuitry from high-voltage stress up to 14V at DC and
U With both an external power supply (USB or adapter)
and battery connected:
8V at USB. In OVLO, V remains on, the input switch that
L
U When the system load requirements are less than
the input current limit, the battery is charged with
residual power from the input.
sees overvoltage (Q1, Q2, Typical Operating Circuit)
opens, and the appropriate power-monitor output (DOK,
UOK) is high impedance, and CHG is high impedance.
If both DC and USB see overvoltage, both input switches
(Q1 and Q2, Typical Operating Circuit) open and the
charger turns off. The BATT-to-SYS switch (Q3, Typical
Operating Circuit) closes, allowing the battery to power
SYS. An input is also invalid if it is less than BATT, or less
than the DC undervoltage threshold of 3.5V (falling). With
an invalid input voltage, SYS connects to BATT through a
40mI switch (Q3, Typical Operating Circuit).
U When the system load requirements exceed the
input current limit, the battery supplies supplemen-
tal current to the load.
U When the battery is connected and there is no external
power input, the system is powered from the battery.
U When an external power input is connected and there
is no battery, the system is powered from the external
power input.
Input Overcurrent Protection
The current at DC and USB is limited to prevent input
overload. This current limit can be selected to match the
capabilities of the source, whether it is a 100mA or 500mA
USB source, or an AC adapter. When the load exceeds
the input current limit, SYS drops to 75mV below BATT
and the battery supplies supplemental load current.
A thermal-limiting circuit reduces the battery charge
rate and external power-source current to prevent the
MAX8934_ from overheating.
System Load Switch
An internal 40mI MOSFET connects SYS to BATT (Q3
in the Typical Operating Circuit) when no voltage source
is available at DC or USB. When an external source is
detected at DC or USB, this switch is opened and SYS
is powered from the valid input source through the input
limiter.
Thermal Limiting
The MAX8934_ reduces input limiter current by 5%/NC
when its die temperature exceeds +100NC. The system
load (SYS) has priority over the charger current, so low-
ering the charge current first reduces the input current. If
the junction temperature still reaches +120NC in spite of
charge current reduction, no input (DC or USB) current
is drawn, the battery supplies the entire system load,
and SYS is regulated at 75mV below BATT. Note that
this on-chip thermal-limiting circuitry is not related to and
operates independently from the thermistor input.
The SYS-BATT switch also holds up SYS when the system
load exceeds the input current limit. If that should happen,
the SYS-BATT switch turns on so that the battery supplies
additional SYS load current. If the system load continu-
ously exceeds the input current limit, the battery does not
charge, even though external power is connected. This is
not expected to occur in most cases, since high loads usu-
ally occur only in short peaks. During these peaks, battery
energy is used, but at all other times the battery charges.
Adaptive Battery Charging
While the system is powered from DC, the charger
draws power from SYS to charge the battery. If the
charger load plus system load exceeds the input current
limit, an adaptive charger control loop reduces charge
current to prevent the SYS voltage from collapsing.
Maintaining a higher SYS voltage improves efficiency
and reduces power dissipation in the input limiter. The
total current through the switch (Q1 or Q2 in the Typical
Operating Circuit) is the sum of the load current at SYS
and the battery charging current. The MAX8934A limiter
clamps at 5.3V (4.35V for the MAX8934B/MAX8934C/
Input Limiter
The input voltage limiter is essentially an LDO regula-
tor. While in dropout, the regulator dissipates a small
I2R loss through the 0.2I MOSFET (Q1 in the Typical
Operating Circuit) between DC and SYS. With an AC
adapter or USB source connected, the input limiter
distributes power from the external power source to the
system load and battery charger. In addition to the input
limiter’s primary function of passing power to the system
20 _____________________________________________________________________________________
Dual-Input Linear Chargers, Smart Power Selector
with Advanced Battery Temperature Monitoring
MAX9834D), so input voltages greater than 5.3V (4.35V
for the MAX8934B/MAX8934C/MAX8934E) can increase
power dissipation in the limiter. The MAX8934_ input
USB or AC adapter output. Input and charger current
limit are controlled by PEN1, PEN2, R
as shown in Tables 2a and 2b.
, and R
PSET
,
ISET
limiter power loss is (V
be as high as 5.3V for the MAX8934A or 4.35V for the
MAX8934B–MAX8934E. The input limiter power loss is
– V
) x I , where V
may
DC
SYS
DC
SYS
Separate Adapter and USB Connectors
When the AC adapter and USB have separate connec-
tors, the adapter output connects to DC and the USB
source connects to USB. PEN1 is permanently connected
not less than 0.2I x I
. Also note that the MAX8934_
DC2
turns off when any input exceeds 6.9V (typ).
high (to DC or V ). The DC current limit is set by R
,
L
PSET
DC and USB Connections and
while the USB current limit is set by PEN2 and USUS.
Current-Limit Options
Single Common Connector
for USB or Adapter
When a single common connector is used for both AC
adapter and USB sources, the DC input is used for
both input sources. The unused USB inputs should be
grounded when an AC adapter is connected at DC,
PEN1 should be pulled high to select the current limit
Input Current Limit
The input and charger current limits are set as shown in
Tables 2a and 2b. It is often preferable to change the
input current limit as the input power source is changed.
The MAX8934_ facilitates this by allowing different input
current limits for DC and USB as shown in Tables 2a
and 2b.
set by R
. When a USB source is connected, PEN1
PSET
When the input current limit is reached, the first action
taken by the MAX8934_ is to reduce the battery charge
current. This allows the regulator to stay in dropout, or
at 5.3V (MAX8934A), during heavy loads, thus reducing
power dissipation. If, after the charge current is reduced
to 0mA, the load at SYS still exceeds the input current
limit, SYS voltage begins to fall. When the SYS voltage
drops to BATT, the SYS-to-BATT switch turns on, using
battery power to support the system load during the load
peak. The MAX8934_ features flexible input connections
(at the DC and USB input pins) and current-limit settings
(set by PEN1, PEN2, PSET, and ISET) to accommodate
nearly any input power configuration. However, it is
expected that most systems use one of two external
power schemes: separate connections for USB and an
AC adapter, or a single connector that accepts either
should be low to select 500mA, 100mA, or USB suspend
(further selected by PEN2 and USUS). PEN1 can be
pulled up by the AC adapter power to implement hard-
ware adapter/USB selection.
USB Suspend
Driving USUS high when PEN1 is low turns off charging,
as well as the SYS output and reduces input current to
190FA to accommodate USB suspend mode.
Power Monitor Outputs (UOK, DOK)
DOK is an open-drain output that pulls low when the DC
input has valid power. UOK is an open-drain output that
pulls low when the USB input has valid power. A valid
input for DC or USB is between 4.1V and 6.6V. If a single
power-OK output is preferred, DOK and UOK can be
Table 2a. Input Limiter Control Logic (MAX8934A/MAX8934B/MAX8934C/MAX8934E)
POWER
SOURCE
DC INPUT
CURRENT LIMIT CURRENT LIMIT
USB INPUT
MAXIMUM CHARGE
PEN1
PEN2
USUS
DOK
UOK
CURRENT*
AC adapter at
DC input
L
X
H
X
X
3000V/R
3000V/R
ISET
PSET
USB input off;
DC input has
priority
L
L
X
X
X
L
L
L
L
L
L
X
X
X
H
L
L
L
475mA
95mA
475mA
95mA
0
USB power at
DC input
L
X
H
L
H
L
USB suspend
H
H
H
475mA
95mA
USB power at
USB input; DC
unconnected
3000V/R
ISET
L
No DC input
X
H
USB suspend
0
0
DC and USB
unconnected
H
H
X
X
X
No USB input
*Charge current cannot exceed the input current limit. Charge may be less than the maximum charge current if the total SYS load
exceeds the input current limit.
______________________________________________________________________________________ 21
Dual-Input Linear Chargers, Smart Power Selector
with Advanced Battery Temperature Monitoring
Table 2b. Input Limiter Control Logic (MAX8934D)
FEATURE
DC INPUT
USB INPUT
NOTES
Absolute Maximum Rating
16V
9V
—
Set by R
, PEN1, PEN2, and
USUS;
2A (max)
Set by R
PEN2, and USUS;
1.5A (max)
, PEN1,
PSET sets the same input
current limit for DC and USB
paths.
PSET
PSET
Input Current Limit
DC INPUT
CURRENT
LIMIT
USB INPUT
CURRENT
LIMIT
MAXIMUM
CHARGE
CURRENT
POWER
DOK
UOK
PEN1
PEN2
USUS
SOURCE
AC Adapter
L
X
H
X
X
3000V/R
3000V/R
3000V/R
3000V/R
PSET
ISET
at DC
USB Input
Off; DC input
has priority
L
X
X
X
X
L
L
L
L
H
L
X
H
L
X
L
L
H
L
L
L
L
PSET
ISET
L
L
475mA
95mA
475mA
95mA
0
USB Power
at DC
L
L
L
X
H
L
USB suspend
H
H
H
H
H
H
L
3000V/R
3000V/R
3000V/R
PSET
ISET
ISET
600V/R
PSET
USB Power
at USB;
DC Open
H
L
475mA
475mA
95mA
L
95mA
No DC input
H
H
L
X
X
X
X
H
X
USB suspend
0
0
DC and
USB Open
H
No USB input
wire-ORed together. The combined output then pulls low
if either USB or DC is valid.
support the load during input power transitions. When
the charger is turned on, charge current ramps from
zero to the ISET current value in typically 1.5ms. Charge
current also ramps when transitioning to fast-charge
from prequal and when changing the USB charge cur-
rent from 100mA to 500mA with PEN2. There is no dI/dt
limiting, however, if ISET is changed suddenly using a
Soft-Start
To prevent input transients that can cause instability in
the USB or AC adapter power source, the rate of change
of input current and charge current is limited. When a
valid DC or USB input is connected, the input current
limit is ramped from zero to the set current-limit value
(as shown in Tables 2a and 2b). If DC is connected with
no USB power present, input current ramps in 1.5ms. If
DC is connected with USB already present, input current
ramps in 50Fs. When USB is connected with no DC pres-
ent, input current also ramps in 50Fs. If USB is connect-
ed with DC already present, the USB input is ignored.
switch at R
.
ISET
Battery Charger
The battery charger state diagram is illustrated in Figure
8. With a valid DC or USB input, the battery charger
initiates a charge cycle when the charger is enabled. It
first detects the battery voltage. If the battery voltage is
less than the BATT prequal threshold (3.0V), the charger
enters prequal mode and charges the battery at 10% of
the maximum fast-charge current. This reduced charge
rate ensures that the maximum fast-charge current set-
ting does not damage a deeply discharged battery.
Once the battery voltage rises to 3.0V, the charger tran-
sitions to fast-charge mode and applies the maximum
charge current. As charging continues, the battery volt-
age rises until it approaches the battery regulation volt-
If an adapter is plugged into DC while USB is already
powered, the input current limit reramps from zero back
up to the DC current limit so that the AC adapter does
not see a load step. During this transition, if the input
current limit is below the SYS load current, the battery
supplies the additional current needed to support the
load. Additionally, capacitance can be added to SYS to
22 _____________________________________________________________________________________
Dual-Input Linear Chargers, Smart Power Selector
with Advanced Battery Temperature Monitoring
age where charge current starts tapering down. When
charge current decreases to 10% of the fast-charge
MONITORING THE BATTERY
CHARGE CURRENT WITH V
ISET
current, the charger enters a brief 15s top-off, (60min
for the MAX8934B and MAX8934D) and then charging
stops. If the battery voltage subsequently drops below
the recharge threshold, charging restarts and the timers
reset.
1.5
Charge Enable (CEN)
When CEN is low, the charger is on. When CEN is high,
the charger turns off. CEN does not affect the SYS out-
put. In many systems, there is no need for the system
controller (typically a microprocessor) to disable the
charger, because the MAX8934_ Smart Power Selector
circuitry independently manages charging and adapter/
battery power hand-off. In these situations, CEN can be
connected to ground.
V
ISET
0
Setting the Charge Current
ISET adjusts charge current to match the capacity of the
battery. A resistor from ISET to ground sets the maximum
fast-charge current:
2000 (1.5V/R )
ISET
DISCHARGING
0
BATTERY CHARGING CURRENT (A)
Figure 4. Monitoring the Battery Charge Current with V
ISET
I
= 2000 x 1.5V/R = 3000V/R
ISET ISET
CHGMAX
reduces charge current. This prevents the charger from
overloading the input source or overheating the system.
Determine the I
value by considering the char-
CHGMAX
acteristics of the battery. It is not necessary to limit the
charge current based on the capabilities of the expected
AC adapter/USB charging input, the system load, or
thermal limitations of the PCB. The MAX8934_ automati-
cally adjusts the charging algorithm to accommodate
these factors.
Charge Termination
When the charge current falls to the termination thresh-
old and the charger is in voltage mode, charging is
complete. Charging continues for a brief 15s top-off
period (60min for the MAX8934B and MAX8934D) and
then enters the DONE state where charging stops. The
) is set to 10% of the fast-
charge current setting. Note that if charge current falls
to I as a result of the input or thermal limiter, the
Monitoring the Charge Current
In addition to setting the charge current, ISET can also
be used to monitor the actual current charging the bat-
tery. See Figure 4. The ISET output voltage is:
DONE current threshold (I
DONE
DONE
charger does not enter the DONE state. For the charger
to enter the DONE state, the charge current must be
V
ISET
= I
x 1.5V/I
= I
x R /2000
ISET
CHG
CHGMAX
CHG
less than I
, the charger must be in voltage mode,
TERM
where I
is the set fast-charge current and I
CHG
CHGMAX
and the input or thermal limiter must not be reducing the
charge current. The charger exits the DONE state, and
fast-charge resumes if the battery voltage subsequently
drops 104mV or if CEN is cycled.
is the actual battery charge current. A 1.5V output indi-
cates the battery is being charged at the maximum set
fast charge current; 0V indicates no charging. This volt-
age is also used by the charger control circuitry to set
and monitor the battery current. Avoid adding more than
10pF capacitance directly to the ISET pin. If filtering of
the charge-current monitor is necessary, add a resistor
of 100kI or more between ISET and the filter capacitor
to preserve charger stability.
Charge Status Outputs
Charge Output (CHG)
CHG is an open-drain, active-low output that is low dur-
ing charging. CHG is low when the battery charger is in
its prequalification and fast-charge states. When charge
current falls to the charge termination threshold and the
charger is in voltage mode, CHG goes high impedance.
CHG goes high impedance if the thermistor causes the
charger to enter temperature suspend mode.
Note that the actual charge current can be less than the
set fast-charge current when the charger enters voltage
mode or when the input current limiter or thermal limiter
______________________________________________________________________________________ 23
Dual-Input Linear Chargers, Smart Power Selector
with Advanced Battery Temperature Monitoring
When the MAX8934_ is used with a microprocessor (FP),
connect a pullup resistor between CHG and the logic I/O
voltage to indicate charge status to the FP. Alternatively,
CHG can sink up to 20mA for an LED indicator.
Thermistor Monitor
The MAX8934_ thermistor monitor is configured to
execute JEITA recommendations regarding Li+/Li-Poly
battery charging by adjusting the fast charge current
and/or the charge termination voltage accordingly (see
Figures 6 and 7). Connect the THM input to an external
negative temperature coefficient (NTC) thermistor to
monitor battery or system temperature. Since the therm-
istor monitoring circuit employs an external bias resistor
from THM to THMSW, the thermistor is not limited only
to 10kI (at +25NC). Any thermistor resistance can be
Charge DONE Output (DONE)
DONE is an open-drain, active-low output that goes low
when charging is complete. The charger enters its DONE
state 15s (60min for the MAX8934B and MAX8934D)
after the charge current falls to the charge-termination
threshold and the charger is in voltage mode. The char-
ger exits the DONE state, and fast-charge resumes, if the
battery voltage subsequently drops 104mV, or if input
power or CEN is cycled. When the MAX8934_ is used in
conjunction with a FP, connect a pullup resistor between
DONE and the logic I/O voltage to indicate charge status
to the FP. Alternatively, DONE can sink up to 20mA for
an LED indicator.
used as long as the value of R
is equivalent to
THMSW
the thermistor’s +25NC resistance. The MAX8934_ THM
thresholds are optimized for a thermistor Beta of 3964
or 3477 (see the Selector Guide). The general relation
of thermistor resistance to temperature is defined by the
following equation:
1
1
β
-
Fault Output (FLT) and Charge Timer
FLT is an open-drain, active-low output that goes low
during a battery fault. The fault state occurs when either
the prequal or fast-charge timer expires. The prequal
T+273°C 298°C
R
= R × e
25
T
where:
and fast-charge fault timers are set by C
:
R
T
= The resistance in ohms of the thermistor at
temperature T in Celsius
CT
C
CT
PREQUAL: t
= 30min ×
PQ
R
25
= The resistance in ohms of the thermistor at
+25NC
0.068FF
C
CT
0.068FF
A = The material constant of the thermistor
T = The temperature of the thermistor in NC
FAST CHARGE:t
= 300min ×
FC
Charging is suspended when the thermistor tempera-
TOP− OFF:t
=15s (60 minutes for the
TO
ture is out of range (V
> V
> V
). The
THM_T4
THM_T1
THM
MAX8934B and MAX8934D)
charge timers are also suspended and hold their state
but no fault is indicated. When the thermistor comes
back into range, charging resumes and the charge timer
continues from where it left off.
While in fast-charge mode, a large system load or device
self-heating can cause the MAX8934_ to reduce charge
current. Under these circumstances, the fast-charge
timer adjusts to ensure that adequate charge time is still
allowed. Consequently, the fast-charge timer is slowed
by 2x if charge current is reduced below 50% of the pro-
grammed fast-charge level. If charge current is reduced
to below 20% of the programmed level, the fast-charge
timer is paused. The fast-charge timer is not adjusted
if the charger is in voltage mode where charge current
reduces due to current tapering under normal charging.
The THMEN input controls THMSW and the thermistor
monitor circuitry when the battery charger is disabled,
providing the user with the means to minimize the bat-
tery current drain caused by the thermistor monitor. The
THMEN input is ignored while the battery is charging,
since the thermistor must be monitored at all times.
While charging, the thermistor monitor is used to auto-
matically adjust the charge termination voltage and/or
the fast-charge current, depending on the sensed bat-
tery temperature and the safety region set at the factory.
If the battery temperature exceeds the THM hot overtem-
perature threshold and THMEN is high, the OT flag pulls
low. Typical systems connect OT to a FP input so that the
system can safely shut down.
To exit a fault state, toggle CEN or remove and reconnect
the input source(s). Note also that thermistor out of range
or on-chip thermal-limit conditions are not considered
faults. When the MAX8934_ is used in conjunction with a
FP, connect a pullup resistor between FLT and the logic
I/O voltage to indicate fault status to the FP. Alternatively,
FLT can sink up to 20mA for an LED indicator.
24 _____________________________________________________________________________________
Dual-Input Linear Chargers, Smart Power Selector
with Advanced Battery Temperature Monitoring
SYS
LOW-I , ALWAYS-ON 3.3V LDO
Q
TRACKS SYS WHEN DC AND USB ARE NOT
PRESENT, THE BATTERY IS BEING
LDO
DISCHARGED, AND V
P 3.3V.
BATT
CHG
VINT
THMEN
THMSW
CHG
CHG
CHARGER
CONTROL
R
THMSW
T4
(60NC)
THM
-
VINT
+
VINT
VINT
T
OT
CHG
T3
(45NC)
-
THERMISTOR
MONITOR
+
CHG
VINT
VINT
T2
(10NC)
+
-
CHG
VINT
VINT
T
OT
-
(75NC)
+
CHG
THMEN
VINT
VINT
T1
+
-
(0NC)
CHG
Figure 5. Thermistor Monitor Details
______________________________________________________________________________________ 25
Dual-Input Linear Chargers, Smart Power Selector
with Advanced Battery Temperature Monitoring
T1
T2
T3
T4
T1
T2
T3
T4
4.2
4.2
4.1
4.075
4.1
4.075
4.0
4.0
0
10
T2
25
45
60
T4
85
0
10
T2
25
45
60
T4
85
TEMPERATURE (NC)
TEMPERATURE (NC)
T1
T3
T1
T3
C
C
0.5C
0.5C
0
10
25
45
60
85
0
10
25
45
60
85
TEMPERATURE (NC)
TEMPERATURE (NC)
Figure 6. Safety Region 1: Fast-Charge Currents and Charge
Termination Voltages
Figure 7. Safety Region 2: Fast-Charge Currents and Charge
Termination Voltages
26 _____________________________________________________________________________________
Dual-Input Linear Chargers, Smart Power Selector
with Advanced Battery Temperature Monitoring
CEN = HIGH
OR
NOT READY
REMOVE AND RECONNECT
UOK AND DOK = HIGH-Z
THE INPUT SOURCE(S)
CHG = HIGH-Z
FLT = HIGH-Z
DONE = HIGH-Z
ANY STATE
I
= 0mA
CHG
TOGGLE CEN
OR REMOVE AND RECONNECT
THE INPUT SOURCE(S)
UOK OR DOK = LOW
CEN = 0
RESET TIMER
STATE DIAGRAM IS FOR 10NC < TEMP < +45NC,
OUTSIDE OF THIS RANGE SEE FIGURE 7
PREQUAL
UOK OR DOK = LOW
CHG = LOW
TIMER > t
PQ
FLT = HIGH-Z
DONE = HIGH-Z
0V P V
P 3V
BATT
I
= I
10
CHG CHGMAX
FAULT
V
> 3V,
BATT
V
< 2.82V,
BATT
UOK AND DOK = LOW
CHG = HIGH-Z
FLT = LOW
RESET TIMER
RESET TIMER
DONE = HIGH-Z
FAST-CHARGE
I
= 0mA
CHG
UOK OR DOK = LOW
CHG = LOW
FLT = HIGH-Z
DONE = HIGH-Z
V
< 2.82V
BATT
RESET TIMER
3V P V
P 4.2V
BATT
I
= I
CHG CHGMAX
TIMER > t
FC
I
< I
BATT
CHG DONE
(TIMER SLOWED BY 2X IF
< I /2, AND
AND V
= 4.2V
I
CHG CHGMAX
AND THERMAL
OR OUTPUT LIMIT
NOT EXCEEDED
RESET TIMER
PAUSED IF I
< I
/5
CHG CHGMAX
I
> I
CHG DONE
WHILE BATT < 4.2V)
RESET TIMER
TOP-OFF
(PQ, FC, TOP-OFF)
ANY CHARGING
STATE
UOK OR DOK = LOW
CHG = HIGH-Z
FLT = HIGH-Z
V
< 4.1V
BATT
V
< V
< V
V
> V
> V
DONE = HIGH-Z
BATT = 4.2V
THM_T1
THM
THM_T4
THMT1
THM THMT4
RESET TIMER
TIMER RESUME
TIMER SUSPEND
I
= I
CHG DONE
TEMPERATURE
SUSPEND
= 0mA
TIMER > 15s (MAX8934A/MAX8934C
/MAX8934E)
TIMER > 60min (MAX8934B/MAX8934D)
I
CHG
UOK OR DOK = PREVIOUS STATE
CHG = HIGH-Z
FLT = HIGH-Z
DONE
DONE = HIGH-Z
UOK OR DOK = LOW
CHG = HIGH-Z
FLT = HIGH-Z
V
THM
< V
THM_OT
V
> V
THM_OT
THM
DONE = LOW
4.1V < V
< 4.2V
= 0mA
BATT
OVERTEMP
OT = LOW
I
CHG
Figure 8. Charger State Diagram
______________________________________________________________________________________ 27
Dual-Input Linear Chargers, Smart Power Selector
with Advanced Battery Temperature Monitoring
Always-On LDO
The ultra-low quiescent current LDO is always on and is
preset to an output voltage of 3.3V. The LDO provides
up to 30mA output current. When DC and USB are inval-
id and the battery is discharging, the LDO output volt-
Power Dissipation
PCB Layout and Routing
Good design minimizes ground bounce and voltage
gradients in the ground plane. GND should connect to
the power-ground plane at only one point to minimize the
effects of power-ground currents. Battery ground should
connect directly to the power-ground plane. Connect
GND to the exposed pad directly under the IC. Use mul-
tiple tightly spaced vias to the ground plane under the
exposed pad to help cool the IC. Position input capaci-
tors from DC, SYS, BATT, and USB to the power-ground
plane as close as possible to the IC. Keep high current
traces such as those to DC, SYS, and BATT as short and
wide as possible. Refer to the MAX8934 Evaluation Kit
for a suitable PCB layout example.
age tracks V
as it drops below 3.3V. A 1FF ceramic
SYS
capacitor connected from LDO to GND is recommended
for most applications.
Table 3. Package Thermal Characteristics
28-PIN 4mm x 4mm THIN QFN
SINGLE-LAYER PCB
Continuous 1666.7mW
Power (derate 20.8mW/NC
Dissipation above +70NC)
MULTILAYER PCB
2286mW
(derate 28.6mW/NC
above +70NC)
B
48NC/W
3NC/W
35NC/W
3NC/W
JA
JC
Chip Information
B
PROCESS: BiCMOS
Pin Configuration
Ordering Information
TOP VIEW
PART
TEMP RANGE
-40NC to +85NC
-40NC to +85NC
-40NC to +85NC
-40NC to +85NC
PIN-PACKAGE
28 Thin QFN-EP*
28 Thin QFN-EP*
28 Thin QFN-EP*
28 Thin QFN-EP*
MAX8934BETI+
MAX8934CETI+
MAX8934DETI+
MAX8934EETI+
21 20 19 18 17 16 15
14
13
CHG 22
SYS 23
THM
GND
12 USUS
24
25
26
27
28
SYS
OT
+Denotes a lead(Pb)-free/RoHS-compliant package.
*EP = Exposed pad.
MAX8934A–
MAX8934E
ISET
CT
11
10
9
DOK
UOK
FLT
GND
*EP
6
8
V
L
1
2
3
4
5
7
THIN QFN
*EXPOSED PAD
Selector Guide
USB INPUT CURRENT
SAFETY
REGION**
THERMISTOR
PART
SYS VOLTAGE (V)
TOP-OFF TIMER
LIMIT (max)
BETA†
500mA
500mA
500mA
1.5A
MAX8934AETI+
MAX8934BETI+
MAX8934CETI+
MAX8934DETI+
MAX8934EETI+
1
1
1
1
1
5.3
3964
3477
3964
3477
3477
15s
60min
15s
4.35
4.35
4.35
4.35
60min
15s
500mA
**For safety region 2, contact factory.
†For thermistor Beta = 3477, contact factory.
28 _____________________________________________________________________________________
Dual-Input Linear Chargers, Smart Power Selector
with Advanced Battery Temperature Monitoring
Package Information
For the latest package outline information and land patterns, go to www.maxim-ic.com/packages. Note that a “+”, “#”, or “-” in the
package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing pertains to the
package regardless of RoHS status.
PACKAGE TYPE
PACKAGE CODE
DOCUMENT NO.
21-0139
28 TQFN-EP
T2844+1
______________________________________________________________________________________ 29
Dual-Input Linear Chargers, Smart Power Selector
with Advanced Battery Temperature Monitoring
Package Information (continued)
For the latest package outline information and land patterns, go to www.maxim-ic.com/packages. Note that a “+”, “#”, or “-” in the
package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing pertains to the
package regardless of RoHS status.
30 _____________________________________________________________________________________
Dual-Input Linear Chargers, Smart Power Selector
with Advanced Battery Temperature Monitoring
Revision History
REVISION
NUMBER
REVISION
DATE
PAGES
CHANGED
DESCRIPTION DATE
0
1
2/10
3/10
Initial release
Added lead temperature and tightened BATT regulation voltage specs
—
2, 4
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.
Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600
31
©
2010 Maxim Integrated Products
Maxim is a registered trademark of Maxim Integrated Products, Inc.
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