Datasheet

23
LTC1325
Information furnished by Linear Technology Corporation is believed to be accurate and reliable.
However, no responsibility is assumed for its use. Linear Technology Corporation makes no represen-
tation that the interconnection of its circuits as described herein will not infringe on existing patent rights.
LABEL MNEMONIC OPERAND COMMENTS
LDAA #$51 Write control byte to the SPCR
STAA $1028
LDAA #$39 Setup Port D DDRD
STAA $1009 Port D Bit 0 is CS
LDX #$1000 Load port base ADDR
CSLOW BCLR $08,X,#$01 Take CS low
LDAA #$02 Send Byte #1 (MSB) with
STAA $102A START bit
LOOP1 TST $1029 Check for SPI transfer
BPL LOOP1 complete bit
LDAA #$24 Send Byte 2
STAA $102A
LOOP2 TST $1029 Check for SPI transfer
BPL LOOP2 complete bit
LDAA #$03 Send Byte 3
STAA $102A
LOOP3 TST $1029 Check for SPI transfer
BPL LOOP3 complete bit
LDAA #$C0 Send Byte 4
STAA $102A
TYPICAL APPLICATION
U
LABEL MNEMONIC OPERAND COMMENTS
LOOP4 TST $1029 Check for SPI transfer
BPL LOOP4 complete bit
LDAA $102A Get A/D high byte
ANDA #$03 Mask off unwanted bits
STAA HIDATA Store in user memory
LDAA #$00 Send dummy Byte #1
STAA $102A
LOOP5 TST $1029 Check for SPI transfer
BPL LOOP5 complete bit
LDAA $102A Get A/D low byte
STAA LODATA Store in user memory
LDAA #$00 Send dummy Byte #2
STAA $102A
LOOP6 TST $1029 Check for SPI transfer
BPL LOOP6 complete bit
LDAA $102A Get STATUS byte
STAA STATUS Store in user memory
BSET $08,X,#$01 Raise CS high
BRA CSLOW Loop for continuous readings
APPLICATIONS INFORMATION
WUU
U
Wide Voltage Battery Charger
NOTE 1: NEEDED WHEN V
DC
> 16V OR MAXIMUM 
BATTERY VOLTAGE, V
BAT
> 16V.
NOTE 2: REGULATOR. OMIT THIS BLOCK AND SHORT 
VDD TO V
DC
WHEN V
DC
< 16V.
NOTE 3: LEVEL SHIFTER. OMIT THIS BLOCK AND SHORT 
PGATE TO P1 GATE WHEN V
DC
< 16V.

1325 TA02
NOTE 7: OPTIONAL DIODE TO PREVENT BATTERY
DRAIN WHEN THE CHARGING SUPPLY IS POWERED
DOWN (SEE SECTION 2, HARDWARE DESIGN
PROCEDURE).

R
SENSE
P1
IRF9Z30
V
DC
25V
R8
100Ω
C
F

1µF
V
DD

PGATE
DIS
V
BAT

T
BAT

T
AMB

V
IN

SENSE
FILTER
REG
D
OUT

D
IN

CS
CLK
LTF
MCV
HTF
GND
R1
R11
220Ω
1/2W
R2
R3
R4
+
C
REG

4.7µF
MPU
(e.g. 8051)
p1.4
p1.3
p1.2
+
C1
1µF
C2
0.1µF
R13
R6
R
TRK
V
BAT
R
DIS
N1
IRF830
C3
500pF

THERM 2
R5
LTC1325
THERM 1
R7
L1
62µH
R9
NOTE 5
NOTE 3
NOTE 1
NOTE 1
NOTE 2
R10
D1
1N5818

D3
1N4740A
D4
1N4744A
15V
R12
100k
NOTE 1
NOTE 4
D2
1N4744A
15V
NOTE 6
+
C4
22µF
R14
100Ω
MBR320
NOTE 7
C5

0.1µF
NOTE 4: ZENER TO CLAMP V
BAT
TO BELOW V
DD
. 
OMIT WHEN V
DC
< 16V.
NOTE 5: EXTERNAL BATTERY DIVIDER. NEEDED WHEN
MAXIMUM BATTERY VOLTAGE, V
BAT
> 16V.
NOTE 6: V
IN
IS AN UNCOMMITTED A/D CHANNEL.