UCC5340
PRELIMINARY
11/95
BLOCK DIAGRAM
Micro Power, 90 A Typical
Operating Current
3.3V or 5V Operation
8-Pin SOIC Package
1 cm to 1 Meter IrDA Link
Compliance
Directly Interfaces to IrDA
Compatible UARTS and Super I/O
Chips
Supports Data Rates from 2400 to
115.2KBits/Second
CMOS/TTL Compatible Output
ASK Modulation Compatible
Drop in compatible with Irvine
Sensor SIR2
The UCC5340 is a dual voltage, micropower, IrDA (Infrared Data Associa-
tion) compliant receiver. It's high gain photodiode input amplifier incorpo-
rates a unique limiting circuit which permits operation over a very wide
dynamic input range. The integrated bandpass filter includes additional
limiting circuitry, further reducing device recovery time requirements, al-
lowing the UCC5340 to directly interface with IrDA compatible detector di-
odes.
The output is capable of driving a 40pF load at CMOS/TTL levels for direct
interfacing to IrDA compliant UARTs or Super I/O devices over a 2400BPS
to 115.2kBPS range.
A control pin is provided to allow operation with either 3.3V or 5V supplies.
The circuit requires only 90 A (nominal) operating current in either config-
uration. An internal 2k
resistor is provided for decoupling the detector
supply, to minimize the number of external components required.
IrDA Receiver
FEATURES
DESCRIPTION
UDG-95126
* Pins 3 and 6 MUST be connected to ground.
2
UCC5340
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNITS
Supply Current, I
DD
No Load, I
DETANODE
= 1
A
90
150
A
Detector Decoupling Resistance, R
DD
2.0
3.0
k
+5VSEL Input Leakage
-
10
10
A
Detector Amplifier
I
PDmax
VDD = 3V
3
4
mA
VDD = 5V
5
mA
Input Resistance, R
IN
I
DETECTOR
= 1
A
20
k
Detection Threshold
1
A DC Ambient Background Current
150
nA
Noise Current, I
N
(rti)
Bandwidth = 0 to 650kHz
6
nA(rms)
Signal to Noise Ratio
I
DETANODE
= 400nA
12
Lower Bandwidth
20
40
kHz
Upper Bandwidth
0.65
1
MHz
Digital Output
Output High, V
OH
I
LOAD
=
-
100
A
2.4
V
Output Low, V
OL
I
LOAD
= 0.8mA
0.4
V
AC Parameters
Rise Time, T
r
100
200
ns
Fall Time, T
f
100
200
ns
Pulse Width, T
w
Tw, Input = 1.6
s, I
DETANODE
= 400nA
2
s
Pulse Jitter, T
j
200
ns
Pulse Delay, T
d
2
s
ELECTRICAL CHARACTERISTICS
Unless otherwise specified, 3.0V
VDD
3.5V and +5VSEL = GND, or
4.5V
VDD
5.5V and +5VSEL = VDD, C
DETECTOR
< 56pF, C
LOAD
= 40pF, 0C < T
A
< 70C, T
A
= T
J
.
CONNECTION DIAGRAM
DIL-8, SOIC-8 (Top View)
N or D Packages
ABSOLUTE MAXIMUM RATINGS
VDD. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
-
0.3V TO +6V
Voltage at +5VSEL (r.t. GND) . . . . . . . . . . . . . . .
-
0.3V to VDD
Input Source Current to DETANODE . . . . . . . . . . . . . . . . 20mA
Package Power Dissipation . . . . . . . . . . . . . . . . . . . . . . . 25mW
Operating Temperature Range . . . . . . . . . . . . . . . 0C to +70C
Storage Temperature Range . . . . . . . . . . . . .
-
55C to +125C
Currents are positive into, negative out of the specified terminal.
Consult Packaging Section of Databook for thermal limitations
and considerations of packages.
RECOMMENDED OPERATING CONDITIONS
VCC Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.0V to 5.5V
+5VSEL: +5 volt selection, strap to DVSS for 3.3 Volt or
to +5 Volts for 5 Volt Operation.
AVSS: Analog Ground, VSS.
DETANODE: High side input of the transimpedance am-
plifier, Photodiode input.
DVSS: Digital Ground, VSS.
OUT: TTL compatible output to the IrDA Compliant
UART/Super I/O.
VCAPDET: Low side of the transimpedance amplifier in-
put, Photodiode input. It should be bypassed to AVSS
with a 10
F capacitor.
VDD: +5 or +3.3 Volts supply.
PIN DESCRIPTIONS
3
UCC5340
TYPICAL APPLICATION
UDG-95127-2
UDG-95128
APPLICATIONS INFORMATION
IrDA Character as it Relates to the UART Character
4
UCC5340
UNITRODE CORPORATION
7 CONTINENTAL BLVD. MERRIMACK, NH 03054
TEL. (603) 424-2410
FAX (603) 424-3460
The IrDA stream is a 1.6 microsecond or 3/16 th of a bit
time pulse for each zero or start bit. The IrDA receiver
must pick up the start bit to frame the character.
The start bit must be passed to the UART to start the
framing. This is critical to get the Start bit, the IR receiver
can not be in saturation from the last information
transfered from the system. This requires a fast receiver
AGC system, amplifiers, and filters that are not in satura-
tion.
The receiver has to work over a very wide ambient IR
level, from sunlit rooms to dark rooms. There is a wide
range of background noise and ambient levels that must
be filtered out.
The receiver sees the light from the transmit side which
can be at a much higher level than the received signal
from another unit. The receiver must come out of satura-
tion fast to recover to pick up the first start bit.
Units that are designed for low power will only use the
1.6 microsecond transmit pulse, others that are not con-
cerned with power may use the 3/16 th of the bit time
over the range of 2400, 9600, 19.2k, 38.4k, 57.6k, and
115.2k BPS. The shortest pulse width allowed is 1.41 mi-
croseconds, the longest pulse at 2400 BPS is 88.55 mi-
croseconds.
Bit Rate
Bit Rate Tolerance
Pulse Width Mini-
mum
Pulse width 3/16
Nominal
Pulse Width Maxi-
mum
Kbits/second
% of Bit Rate
microseconds
microseconds
microseconds
2.4
0.87
1.41
78.13
88.55
9.6
0.87
1.41
19.53
22.13
19.2
0.87
1.41
9.77
11.07
38.4
0.87
1.41
4.88
5.96
57.6
0.87
1.41
3.26
4.34
115.2
0.87
1.41
1.63
2.71
IrDA Standard for Speed and Tolerance
APPLICATIONS INFORMATION (cont.)
The UCC5340 low pass filter input should be bypassed
with a 10
F low ESR tantalum capacitor positioned as
close to VCAPDET as possible. Connections to the
photodiode input should be short, surrounded by ground,
and as direct as possible to reduce stray capacitance and
noise pickup. To obtain maximum performance, a sepa-
rate ground plane and metal EMI shield are recom-
mended. The optical port surface of the transmit LED
and photodiode should be positioned at least one centi-
meter away from an IR optical window and equipment
case to insure that direct sunlight does not impinge onto
the photodiode surface.
APPLICATIONS HINTS
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Copyright
2000, Texas Instruments Incorporated
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