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SC1437ISK-L42TR

Datasheet SC1437ISK-B42TR, SC1437ISK-B45TR, SC1437ISK-B47TR, SC1437ISK-H42TR, SC1437ISK-H45TR Datasheet (Semtech Corporation)

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Page 1
Programmable Trigger Voltage & Timer Delay
POWER MANAGEMENT
Description
The SC143 7 is a battery over voltage detection cir cuit with driver for external MOSFET . The trip point is adjustable with an e xternal resistor divider connected to the SENSE pin. The trip point is preset to a nominal trip voltage of 4.2V if no external divider is used. Other internal trip voltages of 4.5V and 4.7V are available, specified by different part numbers. An internal delay, with two selectable times or bypass, is on-board to suppress accidental over voltage conditions due to glitches on the battery supply volt­age, V+. The delay is externally adjustable by pulling the SEL pin high, low, or left floating. During an actual over voltage condition, the internal driver will pull the over voltage pin (OV) down to the voltage present at the V- pin. This insures the external N-Channel MOSFET will be completely off during an over voltage condition. Supply current during the monitoring mode of operation is ap­proximately 10µA. If an over voltage condition is detected, supply currents increase when the timer is started. A voltage comparator will engage at voltages greater than 6.8V, which bypasses the timer and open circuits the battery by turning off the external MOSFET. This im portant function protects the battery during the timer delay in the event of a charger failure. There are three functional options available. With the B option the OV pin is active low. With the L option the OV pin is active high. With the H option the OV pin is open drain, active high. All options are available in a 5 lead SOT-23 package.
SC1437
Precision Voltage Detector With
Features
! Low quiescent current, less than 10µA typical ! Input voltage range 1.8V to 6.8V ! Adjustable or preset voltage trip point ! Selectable timer delays of 0, 40 and 80ms without use of
external resistor
Applications
! Battery packs ! Portable electronics ! Lithium Ion protection circuits ! Programmable Fuse ! Power Monitoring ! CPU Reset Circuits
Typical Application Circuit
R1
BATTERY
R2
0.1uF
100
1
SEL
4
SENSE
3
OV
SC1437
5
V+
2
V-
0.1uF
VTRIP = 2.1(1+R2/R1)
+
100
-
Revision 01/10/2001
0.476 < (R2/R1) < 2
1
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Page 2
POWER MANAGEMENT
Absolute Maximum Rating
retemaraPlobmySmumixaMstinU
)-V(ottceleSLES7ot3.0-V )-V(otesneSESNES7ot3.0-V
SC1437
)-V(otegatloVylppuS+V+V03ot3.0-V
)-V(ottuptuOegatloVrevOVO8ot3.0-V
tneibmAotnoitcnuJecnatsiseRlamrehT θ egnaRerutarepmeTtneibmAgnitarepOT egnaRerutarepmeTnoitcnuJgnitarepOT
egnaRerutarepmeTegarotST
.ces01)gniredloS(erutarepmeTdaeLT
)ledoMydoBnamuH(gnitaRDSEDSE2Vk
AJ
A
J
GTS
DAEL
652W/C°
58+ot04-C°
521+ot04-C° 051+ot56-C°
003C°
Electrical Characteristics
Unless specified, TA = 25 OC, V+ = 1.8V to 6.3V . V alues in
retemaraPlobmySsnoitidnoCtseTNIMPYTXAMstinU
egatloVylppuStupnI+VegatlovtupniyrettaB 8.13.6 V
tnerruCylppuStupnI+IV7.4=+V;redividlanretnihtiW01 41 Aµ
dlohserhTegatloVrevO
V
-VottcepseRhtiw
tnerruCsaiBtupnII
sisretsyHdlohserhTVOtsyhnoitpOV2.4,-V=ESNES024Vm
tnerruCevirDVOVO
PIRT
NESB
I
LESB
VRD
boldbold
bold apply over the full operating temperature range.
boldbold
noitpOV2.4,-V=ESNES 21.4 2.4 82.4 V noitpOV5.4,-V=ESNES 14.4 5.4 95.4 V noitpOV7.4,-V=ESNES 16.4 7.4 97.4 V
V,rediviDlanretxE
ESNES
V,V1.2+
ESNES
V2.4otV1=2% niPesneS1Aµ niPtceleS1Aµ
noitpOV5.4,-V=ESNES054 noitpOV7.4,-V=ESNES074
redividrotsiser=ESNESV
1.0*
PIRT
noisreVB051Au
V2.4=+V,K001=R;noisreVL&H24Au
yaleDt
egatloVpmalCV emiTffOnruTt emiTffO-nruTt
yaled
PMLC
ffo
tpbffo
+V=LEShtiW0sm
-V=LEShtiW 42 04 65 tcennocon=LEShtiW 84 08 211
V51otV3=egatloVpetS8.6V
Fn1=pacetaghtiwTEFlanretxefoemitffonruT 05 cesµ
rotarapmoCremiTssapyBV8.605cesµ
2 2000 Semtech Corp.
www.semtech.com
Page 3
POWER MANAGEMENT
SC1437
Pin Configuration
T op View
SEL
V-
OV
1
2
3
SOT-23-5L
Marking Information
Top Mark
5
4
V+
SENSE
Ordering Information
)1(
ECIVED
RTXXB-KSI7341CSL5-32-TOS RTXXH-KSI7341CSL5-32-TOS RTXXL-KSI7341CSL5-32-TOS
Notes: (1) Where XX = 42 (4.2V), 45 (4.5V), 47 (4.7V) Only available in tape and reel packaging. A reel contains 3,000 devices.
Bottom Mark
EGAKCAP
7B45
7 = SC143 7 Device Output Option: B = Output active low
L = Output active high H = Output active high, with open drain
Voltage Option: 42 = 4.2V; 45 = 4.5V; 47 = 4.7V
Pin Descriptions
#niPemaNniPnoitcnuFniP
1LES.)tcennoconrodng,+V(noitcelesyaledremitroftupnI 2-V.regrahcfolanimretevitageN 3VO .L&HsnoisrevrofhgihevitcA.BnoisrevrofwolevitcA.tuptuoegatlov-revO 4
5+V.nipylppustupnI
ESNES
yyww
yy = two-digit year of manufacture ww = two-digit week of manufacture
rotinomegatlovrof-VoteiT.tnioppirtegatlovrevognitsujdaroftupniredividegatloV
.noitarugifnoc
2000 Semtech Corp.
3
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Page 4
POWER MANAGEMENT
Block Diagram
V+
SC1437
V+
V+
COMPARATOR
6.8V
CLAMP
SENSE
* Based on version selected 4.2V , 4.5V , 4.7V t B option: Output active low L option: Output active high H option: Output active high, open drain
V+
DELAY TIMER
SEL V-
MUX
DRIVER
4.2V*
V+
OV
t
4 2000 Semtech Corp.
www.semtech.com
Page 5
POWER MANAGEMENT
Applications Information
The SC143 7 can be used as a battery over voltage det ection circuit with driver for an e xternal MOSFET . In this configuration the SC143 7 is capable of protecting the batt ery if the charger circuit fails. Because of its low cost, the SC14 3 7 is an excellent choice in cases when primary discharge protection is not required. The part is an excellent choice for secondary over voltage protection where the battery has primary fault and discharge protection, but could benefit by adding another line of defense against charger failure. The SC143 7 comes in three voltage trip options and three function options. The voltage options are 4.2V , 4.5V or 4.7V. In addition, the trip voltage levels can be adjusted with an external resistive divider .
The SC143 7 also has three separate functional options that affect the OV pin action: With the B option, the OV pin is active low and is used to drive an N-Channel MOSFET. With the H option, the OV pin is active high with open drain to drive a P-Channel MOSFET. Finally, the L option is active high and it's output is 5V logic high for specific use as a voltage detector flag.
SC1437
allows the trip delay to be set to 0S, 40mS or 80mS by applica­tion of a jumper JP2, JP3 or leaving the jumper off, respectively . Configuration of timing delays are shown in T able 1. Once the trip delay is set to the required value the SC1 43 7 will monit or the charger voltage. If the charger voltage equals or exceeds
5.5V the OV pin will transition from high to low (Version B) turning Q1 off, thereby breaking the circuit and protecting the battery from overvoltage. Figure 3 shows the trip delay of 80mS, while Figure 4 shows the trip delay set to 40mS and Figure 5 shows no delay set.
VTRIP
C2
0.1uF
R4 100
FIGURE 1
U1
1
SEL
V+
2
V-
3
OV
SENSE
SC1437
R3
R1
100
5
4
C1
R2
0.1uF
VSENSE+
VSENSE-
Any part can be configured as a voltage detector as shown in Figure 1. A programmable trip delay can be set as indicated by Table 1. In Figure 1, the trip v oltage is set externally b y R1 & R2. while the trip delay is set to 0 seconds plus any propagation delay of the SC14 37 t o allow the MOSFET to turn off, specified by parameter toff.
TT
ABLE 1ABLE 1
T
ABLE 1
TT
ABLE 1ABLE 1
NOITCENNOCLESYALED
+VYALEDON
-VSm04 NEPOSm08
CHARCHAR
CHAR
CHARCHAR
GER OGER O
GER O
GER OGER O
VERVER
VER
VERVER
VV
OLOL
TT
AA
OL
OLOL
GE PRGE PR
T
A
GE PR
TT
AA
GE PRGE PR
V
VV
OO
TECTIONTECTION
O
TECTION
OO
TECTIONTECTION
The SC143 7 configuration for secondary overvoltage protection is shown in Figure 2. This is the Evaluation Board schematic. The Evaluation Board is set up to work with either internal trip voltage or external trip voltage via R1 and R2. It also can set the trip delay to all three values through jumper selection of JP2 and JP3. With CHARGER+ and CHARGER- input applied, the charger voltage will be filtered by R3 and C1. The filtered voltage will then be sensed by the V+ input. In this case the trip voltage can be set to a value other than the internal setting of 4.2V . This is done by using the on-board external resistor divider and removing JP1 shunt jumper that will allow the resistors R1 and R2 to program a trip voltage of 5.75V . The Evaluation Boar d also
VOLTAGE DETECTOR: TRIP DELAY = 0
VTRIP = 2.1(1+R2/R1)
0.476 < (R2/R1) < 2
When using the program resistors R1 & R2, Figure 2, to set an alternate trip voltage, be sure these resistors are placed across the battery on the drain side of the MOSFET. This will eliminat e any voltage drop errors caused by the MOSFET on resistance. Figure 6 and Figure 7 shows the normalized trip voltage variation with respect to temperature. Note that in all cases the trip voltage remains within its 2% specified range. This is true for both the internal trip voltage and externally set trip voltage, however when using an e xternal resistor divider , the tolerance and temperature coefficient of the resistors will add to the overall device err or . Choice of the resistor tolerance and temperature coefficient will depend on your error budget. We also recommend using high value resistors to limit battery current drain. Values between 100K and 1M should suffice without introducing excessive noise into the IC.
CHOOSING THE EXTERNAL MOSFETCHOOSING THE EXTERNAL MOSFET
CHOOSING THE EXTERNAL MOSFET
CHOOSING THE EXTERNAL MOSFETCHOOSING THE EXTERNAL MOSFET
The external switch must be a logic lev el MOSFET. Most logic level MOSFET s ha ve threshold voltages in the 1V range and can handle a gate to source voltage (VGS) of 12V which is well above the clamp voltage of the SC1 43 7. In addition, the selection should be able to handle the charging current of the battery over all temperature ranges. Whether to use a P-Channel or N-Channel MOSFET depends upon the option chosen. The B option requires the use of a N-Channel MOSFET while the H option uses a P-Channel MOSFET .
2000 Semtech Corp.
5
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Page 6
POWER MANAGEMENT
Applications Information Continued
SC1437
1
VBAT+
1
VTRIP
JUMPER IN = I NTERN AL VTRIP SELECT JUMPER OUT = ADJU STABLE VTRIP SELECT
1
VBAT-
JP1
NO JUMPER = 80ms DELAY
R1 576K
R2
12
1M
4
5
1 26 3
7 8
Q1
IRF7805
JP3
0 DELAY
1 2
JP2
40ms D ELAY
1 2
R4 100
C2
0.1uF
1 4 3
U2
SEL SENSE OV
SC1437
5
V+
2
V-
R3 100
C1
0.1uF
1
CHARGER+
1
CHARGER-
FIGURE 2
FIGURE 3: TFIGURE 3: T
FIGURE 3: T
FIGURE 3: TFIGURE 3: T
rip Delarip Dela
rip Dela
rip Delarip Dela
y sey se
y se
y sey se
t tt t
t t
t tt t
Top T race: Charger V oltage, 5V/div Bottom T race: VTRIP , 5V/div Timebase: 20ms/div
o 80mS, JP3 & JP2 Open.o 80mS, JP3 & JP2 Open.
o 80mS, JP3 & JP2 Open.
o 80mS, JP3 & JP2 Open.o 80mS, JP3 & JP2 Open.
FIGURE 4: TFIGURE 4: T
FIGURE 4: T
FIGURE 4: TFIGURE 4: T
rip delarip dela
rip dela
rip delarip dela
y Sey Se
y Se
y Sey Se
t tt t
o 40mS, JP2 Shoro 40mS, JP2 Shor
t t
o 40mS, JP2 Shor
t tt t
o 40mS, JP2 Shoro 40mS, JP2 Shor
Top T race: Charger V oltage, 5V/div Bottom T race: VTRIP , 5V/div
Timebase: 20ms/div
tt
t
tt
ed.ed.
ed.
ed.ed.
6 2000 Semtech Corp.
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Page 7
POWER MANAGEMENT
)
Applications Information Continued
FIGURE 5: TFIGURE 5: T
FIGURE 5: T
FIGURE 5: TFIGURE 5: T
rip delarip dela
rip dela
rip delarip dela
y Sey Se
y Se
y Sey Se
t tt t
o 0mS, JP3 Shoro 0mS, JP3 Shor
t t
o 0mS, JP3 Shor
t tt t
o 0mS, JP3 Shoro 0mS, JP3 Shor
tt
t
tt
ed.ed.
ed.
ed.ed.
FIGURE 6: IntFIGURE 6: Int
FIGURE 6: Int
FIGURE 6: IntFIGURE 6: Int
INTERNAL TRIP VO LTA GE DEVIA TIO N O VER
0.4
0.2 0
-0.2
-0.4
-0.6
DEVIATION (%
-0.8
-1
-40-20020406080100120
ernal Ternal T
ernal T
ernal Ternal T
PloPlo
tttt
ed Aed A
Plo
tt
ed A
PloPlo
tttt
ed Aed A
TEMPERATURE (Degrees C)
rip Vrip V
oltage (4.7V) Deoltage (4.7V) De
rip V
oltage (4.7V) De
rip Vrip V
oltage (4.7V) Deoltage (4.7V) De
gainst Tgainst T
gainst T
gainst Tgainst T
TEMPERATURE
emem
em
emem
perature.perature.
perature.
perature.perature.
SC1437
viationviation
viation
viationviation
4.7V Internal
Top T race: Charger V oltage, 5V/div Bottom T race: VTRIP , 5V/div Timebase: 20ms/div
FIGURE 7FIGURE 7
FIGURE 7
FIGURE 7FIGURE 7
0.2
0.1 0
-0.1
-0.2
-0.3
DEVIATION (%)
-0.4
-0.5
-0.6
: Int: Int
ernal Ternal T
: Int
ernal T
: Int: Int
ernal Ternal T
PloPlo
tttt
ed Aed A
Plo
tt
ed A
PloPlo
tttt
ed Aed A
INTERNA L TRI P VOLTA G E DEVI ATI O N O VER
-40 -20 0 20 40 60 80 100 120
TEMP ERATURE (Degr ees C)
rip Vrip V
oltage (4.2V) Deoltage (4.2V) De
rip V
oltage (4.2V) De
rip Vrip V
oltage (4.2V) Deoltage (4.2V) De
gainst Tgainst T
gainst T
gainst Tgainst T
TEMPERATURE
emem
em
emem
perature.perature.
perature.
perature.perature.
viationviation
viation
viationviation
4.2V Internal
2000 Semtech Corp.
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Page 8
POWER MANAGEMENT
Outline Drawing - SOT23-5
SC1437
Land Pattern - SOT23-5
Contact Information
Semtech Corporation
Power Management Products Division
652 Mitchell Rd., Newbury Park, CA 91320
Phone: (805)498-211 1 F AX (805)498-3804
8 2000 Semtech Corp.
www.semtech.com
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