LTC1955
2
1955fd
pin conFiguraTion
absoluTe MaxiMuM raTings
VBATT, DVCC, CPO, FAULT,
UNDERV to GND ....................................... –0.3V to 6.0V
PRES A/PRES B, DATA, RIN, SYNC, ASYNC,
LD, DIN, SCLK to GND.................–0.3V to (DVCC + 0.3V)
I/O A............................................ –0.3V to (VCCA + 0.3V)
I/O B............................................ –0.3V to (VCCB + 0.3V)
IVCCA/IVCCB.............................................................80mA
VCCA/VCCB Short-Circuit Duration..................... Indefinite
Operating Temperature Range (Note 4).... –40°C to 85°C
Junction Temperature ........................................... 125°C
Storage Temperature Range................... –65°C to 125°C
(Note 1)
32
33
SGND
31 30 29 28 27 26 25
9 10 11 12
TOP VIEW
UH PACKAGE
32-LEAD (5mm
× 5mm) PLASTIC QFN
13 14 15 16
17
18
19
20
21
22
23
24
8
7
6
5
4
3
2
1
DVCC
PRES A
C8A
C4A
I/O A
RST A
CLK A
VCCA
FAULT
UNDERV
NC/NO
PRES B
I/O B
RST B
CLK B
VCCB
SYNC
ASYNC
R
IN
DATA
D
OUT
D
IN
SCLK
LD
SGND
PGND
C–
SV
BATT
PV
BATT
C+
CPO
NC
TJMAX = 125°C, θJA = 34°C/W
EXPOSED PAD (PIN 33) IS SGND, MUST BE SOLDERED TO PCB
orDer inForMaTion
LEAD FREE FINISH
TAPE AND REEL
PART MARKING*
PACKAGE DESCRIPTION
TEMPERATURE RANGE
LTC1955EUH#PBF
LTC1955EUH#TRPBF
1955
32-Lead (5mm
× 5mm) Plastic QFN
–40°C to 85°C
LTC1955IUH#PBF
LTC1955IUH#TRPBF
1955
32-Lead (5mm
× 5mm) Plastic QFN
–40°C to 85°C
LEAD BASED FINISH
TAPE AND REEL
PART MARKING*
PACKAGE DESCRIPTION
TEMPERATURE RANGE
LTC1955EUH
LTC1955EUH#TR
1955
32-Lead (5mm
× 5mm) Plastic QFN
–40°C to 85°C
LTC1955IUH
LTC1955IUH#TR
1955
32-Lead (5mm
× 5mm) Plastic QFN
–40°C to 85°C
Consult LTC Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container.
For more information on lead free part marking, go to: http://www.linear.com/leadfree/
For more information on tape and reel specifications, go to: http://www.linear.com/tapeandreel/
elecTrical characTerisTics
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
Input Power Supply
VBATT Operating Voltage
l
2.7
5.5
V
IPVBATT + ISVBATT Operating Current
VCCA = 5V, VCCB = 0V, ICCA = 0A
VCCA = VCCB = 5V, ICCA = ICCB = 0A
l
250
350
400
500
A
IPVBATT + ISVBATT Shutdown Current
No Cards Present. VCPO = 0V
l
0.75
1.75
A
DVCC Operating Voltage
l
1.7
5.5
V
The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. VPVBATT = VSVBATT = 3.3V, DVCC = 3.3V, unless otherwise noted.