Maxim MAX9547ESA+ Differential video interface chipset Datasheet

19-3873; Rev 3; 10/07
Differential Video Interface Chipset
The MAX9546/MAX9547 differential interface chipset
converts single-ended voltages to differential voltages for
transport and then converts back to single-ended voltages. These devices eliminate costly, bulky, singleended coaxial cables with inexpensive, readily available,
differential shielded (ScTP) or unshielded (UTP) twisted
pairs. The fault detection of the MAX9546 and loss-of-signal detection of the MAX9547 allow proactive and
speedy diagnosis, such as identifying failures in the manufacturing stage and troubleshooting equipment at repair
facilities. The MAX9546/MAX9547 are low-cost, convenient solutions for transporting CVBS/FBAS analog video
signals (PAL or NTSC) through hostile environments.
The MAX9546 driver converts the single-ended input into
a differential output with a 6dB fixed gain to drive a backterminated, DC-coupled differential video output to unity
gain. This DC connection allows the detection of a shortcircuit condition at the differential outputs. The FAULT
output indicates a short-circuit condition including a short
to a high battery condition (VBAT = +16V) or ground.
The MAX9547 receiver converts the differential signal
from the MAX9546 into a single-ended signal. Like the
MAX9546 output, the MAX9547 input survives a short to
a high battery condition or ground. The MAX9547 receiver loss-of-signal output (LOS) operates by detecting the
H-Sync and thus can support both monochrome and
color video signals. The MAX9547 gain is set with an
external impedance between ZT+ and ZT-.
The MAX9546/MAX9547 operate from a 7.5V to 10V
single supply. Both devices include ±15kV ESD Human
Body Model (HBM) protection. The MAX9546/MAX9547
are offered in a thermally enhanced 8-pin SO package
and specified over the -40°C to +85°C extended temperature range.
Features
♦ Fault Detection (MAX9546)
♦ Loss-of-Signal Detection (MAX9547)
♦ Tolerate ±2V Ground-Level Shift between Source
and Load
♦ ±15kV ESD Protection (Human Body Model)
♦ ±8kV—IEC 1000-4-2 Contact Discharge
♦ ±15kV—IEC 1000-4-2 Air-Gap Discharge
♦ Preset 6dB Gain (MAX9546)
♦ Variable Receiver Gain (MAX9547)
♦ 7.5V to 10V Single-Supply Operation
Ordering Information
PINPACKAGE
PART
PKG CODE
DESCRIPTION
MAX9546ESA+
8 SO-EP*
S8E-14
Driver
MAX9547ESA+
8 SO-EP*
S8E-14
Receiver
Note: These devices are specified for -40°C to +85°C temperature range.
+Denotes a lead-free package.
*EP = Exposed paddle.
Pin Configuration appears at end of data sheet.
Typical Operating Circuit
Applications
VCC
VCC
Automotive Video
Car Navigation
ZT+
In-Car Entertainment
Collision Avoidance/Rearview Cameras
ZTOUT+
IN+
OUT-
IN-
IN
Security/CCTV Video
Avionics/In-Flight Entertainment
MAX9547
MAX9546
IOUT
VOUT
CLAMP
FAULT
LOS
________________________________________________________________ Maxim Integrated Products
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.
1
MAX9546/MAX9547
General Description
MAX9546/MAX9547
Differential Video Interface Chipset
ABSOLUTE MAXIMUM RATINGS
IOUT, LOS Short-Circuit Duration to
VCC or GND (MAX9547) .........................................Continuous
Continuous Power Dissipation (TA = +70°C)
8-Pin SO-EP (derate 24.4mW/°C above +70°C) ......1951.2mW
θJC (Note 2).....................................................................7.0°C/W
θJA .................................................................................41.0°C/W
Operating Temperature Range ...........................-40°C to +85°C
Junction Temperature ..................................................... +150°C
Storage Temperature Range .............................-65°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°C
(Voltages are referenced GND.)
VCC to GND ............................................................-0.3V to +11V
IN and FAULT (MAX9546)......................... -0.3V to (VCC + 0.3V)
OUT+, OUT- (MAX9546) (Note 1) .............................-2V to +16V
FAULT Short-Circuit Duration to
VCC or GND (MAX9546) .........................................Continuous
IN+, IN- (MAX9547) (Note 1).....................................-2V to +16V
IOUT, LOS, ZT+, ZT- (MAX9547) ...............-0.3V to (VCC + 0.3V)
Differential Input Voltage (|VIN+ - VIN-|) (MAX9547)...............+5V
Note 1: The Absolute Maximum Ratings of OUT+/OUT- for the MAX9546 and IN+/IN- for the MAX9547 are based on a single-fault
condition, i.e. only one output of MAX9546 (or both outputs together) is shorted to the battery, VCC or GND. The devices will
not survive a double-fault condition, i.e. OUT+ and OUT- shorted to different supplies.
Note 2: Package thermal resistances were obtained using the method described in JEDEC specification JESD51-7, using a 4-layer
board. For detailed information on package thermal considerations see www.maxim-ic.com/thermal-tutorial.
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.
DC ELECTRICAL CHARACTERISTICS—MAX9546
(VCC = +8.5V, RL = 220Ω between OUT+ and OUT-, TA = -40°C to +85°C. Typical values are at TA = +25°C, unless otherwise
noted.) (Note 3)
PARAMETER
SYMBOL
CONDITIONS
Supply Voltage Range
VCC
Guaranteed by PSRR
Quiescent Supply Current
ICC
No load
Voltage Gain
AV
VIN = 1.2VP-P (Note 4)
Input-Voltage Swing
VIN
Guaranteed by AV
Input Clamp Voltage
VCLMP
(Note 5)
Input Clamp Current
ICLMP
(Note 5)
Input Resistance
RIN
Output Common-Mode Voltage
VCOM
Output Impedance
ROUT
Output Fault Current
IF(OUT)
MIN
TYP
MAX
7.5
8.5
10.0
V
64
112
mA
2
2.2
V/V
1.2
VP-P
1.8
3.46
7
(Notes 5, 6)
FAULT Output Logic Level
FAULT Output Leakage Current
2
PSRR
3.25
13
9
OUT+ and/or OUT- to + (VCC - 2V)
2
OUT+ and/or OUT- to +2V
4
OUT+ and/or OUT- to -2V
7
OUT+ and/or OUT- to +16V, VCC
unconnected
6
VCC from 7.5V to
10V (Note 7)
µA
kΩ
3.4
0.1
OUT+ and/or OUT- to +16V
OUT+ or OUT- to -2V, VCC unconnected
Power-Supply Rejection Ratio
V
500
3.0
UNITS
V
Ω
mA
24
Differential mode
45
62
Common mode
46
52
VOL, ISINK = 1.6mA (Note 8)
dB
0.4
0.01
_______________________________________________________________________________________
V
µA
Differential Video Interface Chipset
(VCC = +8.5V, RL = 220Ω across OUT+ and OUT-, TA = -40°C to +85°C. Typical values are at TA = +25°C, unless otherwise noted.)
(Note 3)
PARAMETER
SYMBOL
Large-Signal Bandwidth
Large-Signal Flatness
Slew Rate
SR
Settling Time (0.1%)
CONDITIONS
MIN
PSRR
Common-Mode Balance (Note 9)
CMB
Droop
MAX
UNITS
18
MHz
VIN = 1VP-P, ±0.5dB
15
MHz
OUT+ - OUT-
70
V/µs
tSETTLING VIN = 1VP-P
Power-Supply Rejection Ratio
TYP
VIN = 1VP-P, -3dB
400
ns
f = 100kHz, 100mVP-P ripple
63
dB
f = 100kHz
55
f = 3.58MHz
39
Guaranteed by input current
1
dB
%
Differential Gain
DG
(Note 10)
1.37
%
Differential Phase
DP
(Note 10)
0.14
degrees
SNR
(Note 10)
-62
dB
2T Pulse to Bar Rating
(Note 10)
-0.22
%KF
2T Pulse Response
(Note 10)
0.30
%KF
At 3.58MHz (Note 10)
2.20
ns
SNR (dBRMS)
Group Delay
D/dt
Horizontal Tilt
(Notes 10, 15)
0
%
Vertical Tilt
(Notes 10, 15)
6.62
%
DC ELECTRICAL CHARACTERISTICS—MAX9547
(VCC = +8.5V, GND = 0V, RL = 75Ω, ZZT = 75Ω, TA = -40°C to +85°C. Typical values are at TA = +25°C.) (Note 3)
PARAMETER
SYMBOL
Supply Voltage Range
VCC
Supply Current
ICC
Differential Input Voltage Range
|IN+ - IN-|
Common-Mode Input Voltage
Range
Input Current
CONDITIONS
Guaranteed by PSRR
VIN(P-P)
Guaranteed by CMRR (Note 11)
VCOM
Guaranteed by CMRR (Note 11)
MIN
TYP
MAX
UNITS
7.5
8.5
10.0
V
70
110
mA
1.2
VP-P
5.4
V
6
30
µA
1
4.2
1.0
IIN
Input Offset Current
∆IIN
Input Resistance
RIN
Differential
Voltage Gain
AV
VIN(P-P) = 1.2V, defined as IOUT x (RL / VIN)
80
0.90
Output Voltage
VOB
Output Voltage Swing
VOUT
Maximum Output Current
IOUT
VIN = 1V, ZZT = 0
Power-Supply Rejection Ratio
PSRR
VCC from 7.5V to 10V
1V ≤ VCOM ≤ 5.4V
2V ≤ VCOM ≤ 4.4V
46
70
Common-Mode Rejection Ratio
CMRR
IN+ = IN- = 3.2V
1
µA
kΩ
1.15
V/V
1.2
VP-P
1
V
21
mA
26
34
dB
42
54
dB
_______________________________________________________________________________________
3
MAX9546/MAX9547
AC ELECTRICAL CHARACTERISTICS—MAX9546
MAX9546/MAX9547
Differential Video Interface Chipset
DC ELECTRICAL CHARACTERISTICS—MAX9547 (continued)
(VCC = +8.5V, GND = 0V, RL = 75Ω, ZZT = 75Ω, TA = -40°C to +85°C. Typical values are at TA = +25°C.) (Note 3)
PARAMETER
SYMBOL
LOS Logic Level
CONDITIONS
MIN
LOS Leakage Current
Input Fault Current
TYP
VOL, ISINK = 1.6mA (Note 12)
MAX
UNITS
0.4
V
0.01
IF
IN+ and/or IN- to +16V, RT1 + RT2 = 110Ω
50
IN+ and/or IN- to -2V, RT1 + RT2 = 110Ω
10
IN+ and/or IN- to +16V, VCC unconnected,
RT1 + RT2 = 110Ω
72
IN+ and/or IN- to -2V, VCC unconnected,
RT1 + RT2 = 110Ω
10
µA
mA
AC ELECTRICAL CHARACTERISTICS—MAX9547
(VCC = +8.5V, GND = 0V, RL = 75Ω, ZZT = 75Ω, CL = 50pF, TA = -40°C to +85°C, Typical values are at TA = +25°C.) (Note 3)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
Large-Signal Bandwidth
VIN = 1VP-P, -3dB
20
MHz
Large-Signal Flatness
VIN = 1VP-P, ±0.5dB
15
MHz
SR
50
V/µs
tSETTLING
400
ns
30
dB
Slew Rate
Settling Time (0.1%)
Power-Supply Rejection Ratio
PSRR
f = 100kHz, 100mVP-P ripple
Common-Mode Rejection Ratio
CMRR
f = 100kHz, 100mVP-P ripple
53
dB
760
µs
(Notes 13, 14)
2.65
%
DP
(Notes 13, 14)
0.57
degrees
SNR
(Notes 13, 14)
-72
dB
(Notes 13, 14)
-0.06
%KF
(Notes 13, 14)
0.40
%KF
0
ns
LOS Timeout Period
tLOS
Differential Gain
DG
Differential Phase
SNR (dBRMS)
2T Pulse to Bar Rating
2T Pulse Response
Group Delay
D/dt
At 3.58MHz (Notes 13, 14)
Horizontal Tilt
(Notes 13, 14, 15)
0.10
%
Vertical Tilt
(Notes 13, 14, 15)
1.16
%
4
_______________________________________________________________________________________
Differential Video Interface Chipset
(VCC = +8.5V, RL = 220Ω across OUT+ and OUT-, RL = 75Ω (MAX9547), ZZT = 75Ω, TA = -40°C to +85°C. Typical values are at TA =
+25°C, unless otherwise noted.) (Note 3)
PARAMETER
SYMBOL
Differential Gain
DG
Differential Phase
DP
Signal-to-Noise Ratio
SNR
2T Pulse-to-Bar Rating
2T Pulse Response
Group Delay
D/dt
CONDITIONS
MIN
TYP
MAX
UNITS
3.8
%
0.6
degrees
5MHz lowpass, 100kHz highpass,
VIN = 1VP-P
80
dB
2T = 250ns, bar time is 18µs, the beginning
3.5% and the ending 3.5% of the bar time is
ignored
0.2
%
2T = 250ns
0.25
%
At 3.58MHz
10
ns
Horizontal Tilt
(Note 15)
0.12
%
Vertical Tilt
(Note 15)
0.26
%
Note 3:
Note 4:
Note 5:
Note 6:
Note 7:
Note 8:
Note 9:
Note 10:
Note 11:
Note 12:
Note 13:
Note 14:
Note 15:
All devices are 100% production tested at TA = +25°C. All temperature limits are guaranteed by design.
Defined as differential output to single-ended input.
Input is AC-coupled.
The RC time constant (3Hz) formed by the source resistance (RS) and coupling capacitor (CIN) is usually used for lead
compensation of the active clamp. The source resistance is 400Ω max. The clamp should remain stable in this condition.
Differential mode is measured as (OUT+ - OUT-). Common mode is measured as OUT+ + OUT2
A fault is when the outputs both sink and source current and the amount of extra current sink or source is greater than 3mA.
Common-mode balance is measured as 20log((OUT+ - OUT-) / (OUT+ + OUT-)).
2
These results were measured with a MAX4144 receiver, other receivers may affect results.
Ground between MAX9546 and MAX9547 can be a ±2V difference.
A loss-of-signal is when the input video signal of the MAX9547 does not change (cross 100mV level from sync tip) for 10
video lines.
These results were measured with a MAX4447 transmitter and a MAX4012 buffer amplifier with a gain of 4. Using other
devices may affect results.
MAX9547 topology shown in Figure 3.
Input capacitor for this test is 0.33µF.
_______________________________________________________________________________________
5
MAX9546/MAX9547
AC ELECTRICAL CHARACTERISTICS—MAX9546 Driving MAX9547
Typical Operating Characteristics
(VCC = +8.5V, RL = 220Ω between OUT+ and OUT-, RL = 75Ω (MAX9547), ZZT = 75Ω, TA = +25°C, unless otherwise noted.)
MAX9547 IOUT CURRENT vs. TEMPERATURE
GAIN vs. TEMPERATURE
MAX9546
10
VIN = 1VP-P
7
25
MAX9546 toc02
MAX9546 toc01
8
6
MAX9546 toc03
GAIN vs. FREQUENCY
20
23
MAX9547
-10
MAX9546
4
IIOUT (mA)
0
GAIN (dB)
GAIN (dB)
5
3
MAX9547
2
21
19
1
-20
17
0
-1
-30
0.001
0.1
10
1
-40
-15
-10
35
-15
10
35
60
TEMPERATURE (°C)
TEMPERATURE (°C)
MAX9547 COMMON-MODE REJECTION
RATIO vs. FREQUENCY
MAX9547 COMMON-MODE REJECTION
RATIO vs. TEMPERATURE
MAX9546 INPUT CLAMP CURRENT
vs. TEMPERATURE
-30
-30
CMRR (dB)
-20
10
9
ICLMP (µA)
-10
-20
-40
VRIPPLE = 100mVP-P
fRIPPLE = 10kHz
VCOM = 2V
-40
-50
-60
-60
-70
-70
-80
0.0001
-80
0.001
0.01
0.1
10
1
7
VCOM = 5.4V
-15
FREQUENCY (MHz)
10
35
5
-40
85
60
-15
TEMPERATURE (°C)
140
120
100
80
60
180
160
140
120
100
80
60
40
40
20
20
0
MAX9546 toc08
200
DIFFERENTIAL ROUT (mΩ)
160
35
MAX9546 DIFFERENTIAL OUTPUT
RESISTANCE vs. TEMPERATURE
MAX9546 toc07
180
10
TEMPERATURE (°C)
MAX9547 DIFFERENTIAL INPUT
RESISTANCE vs. TEMPERATURE
DIFFERENTIAL RIN (kΩ)
8
6
-40
200
0
-40
-15
10
35
TEMPERATURE (°C)
60
85
MAX9546 toc06
0
MAX9546 toc05
VRIPPLE = 100mVP-P
-50
6
-40
85
60
FREQUENCY (MHz)
MAX9546 toc04
-10
15
-2
0.01
0
CMRR (dB)
MAX9546/MAX9547
Differential Video Interface Chipset
85
-40
-15
10
35
60
TEMPERATURE (°C)
_______________________________________________________________________________________
85
60
85
Differential Video Interface Chipset
POWER-SUPPLY REJECTION RATIO
vs. TEMPERATURE
POWER-SUPPLY REJECTION RATIO
vs. FREQUENCY
VRIPPLE = 100mVP-P
-10
-20
PSRR (dB)
MAX9547
-30
-40
-50
-50
-70
-70
-80
0.001
0.01
0.1
1
-40
10
-15
10
35
85
60
TEMPERATURE (°C)
FREQUENCY (MHz)
GROUP DELAY vs. FREQUENCY
(MAX9546 DRIVING MAX9547)
DIFFERENTIAL GAIN (MAX9546 DRIVING MAX9547)
MAX9546 toc12
50
MAX9546 toc13
5
4
3
2
1
0
-1
-2
-3
40
1
2
3
4
5
6
DIFFERENTIAL PHASE (MAX9546 DRIVING MAX9547)
1.0
GROUP DELAY (ns)
30
20
10
0.6
0
0.2
-0.2
-10
0.1
-0.6
-1.0
1
10
FREQUENCY (MHz)
1
2
3
4
5
6
OUTPUT RESPONSE TO NTC-7
VIDEO TEST SIGNAL (MAX9546 DRIVING MAX9547)
SIGNAL-TO-NOISE RATIO vs. FREQUENCY
(MAX9546 DRIVING MAX9547)
MAX9546 toc14
0
-10
-20
-30
MAX9546
INPUT
500mV/div
MAX9546 toc15
DIFFERENTIAL GAIN (%)
-40
SNR (dB)
-80
0.0001
MAX9546
-60
MAX9546
DIFFERENTIAL PHASE (deg)
PSRR (dB)
MAX9547
-40
-60
VRIPPLE = 100mVP-P
fRIPPLE = 100kHz
-10
-20
-30
MAX9546 toc10
0
MAX9546 toc09
0
MAX9547
OUTPUT
500mV/div
10µs/div
-50
-60
-70
-80
-90
-100
110
-120
0.1
1
10
FREQUENCY (MHz)
_______________________________________________________________________________________
7
MAX9546/MAX9547
Typical Operating Characteristics (continued)
(VCC = +8.5V, RL = 220Ω between OUT+ and OUT-, RL = 75Ω (MAX9547), ZZT = 75Ω, TA = +25°C, unless otherwise noted.)
Differential Video Interface Chipset
MAX9546/MAX9547
Pin Description (MAX9546)
PIN
NAME
1, 8
VCC
2
IN
3
FAULT
FUNCTION
Power Supply. Connect together and bypass with a 0.1µF in parallel with a 4.7µF capacitor to
GND.
Video Input
Fault Indicator. Active-low, open-drain output. FAULT = low when fault is detected at the output.
FAULT = high when no fault is detected at the output.
4, 5
GND
Ground
6
OUT-
Negative Differential Output
7
OUT+
EP
EP
Positive Differential Output
Exposed Paddle. Connect to GND.
Pin Description (MAX9547)
PIN
NAME
1
IN+
FUNCTION
2
ZT+
Positive Transconductance Terminal
3
ZT-
Negative Transconductance Terminal
4
IN-
Negative Differential Input
5
GND
Ground
6
LOS
Loss-of-Signal Indicator. Active-low, open-drain output. LOS = low when no signal is detected at
the input. LOS = high when signal is present at the input.
7
IOUT
Current Output
8
VCC
Power Supply. Bypass with a 0.1µF capacitor in parallel with a 4.7µF capacitor to GND.
EP
EP
Positive Differential Input
Exposed Paddle. Connect to GND.
Detailed Description
The MAX9546/MAX9547 differential interface chipset
converts single-ended voltages to differential voltages
for transport and then converts back to single-ended
voltages. The chipset is optimized for transporting
CVBS/FBAS analog video signals (PAL or NTSC)
through hostile automotive environments. The
MAX9546 driver includes a fault output (FAULT) that
indicates shorted transmission cables. The MAX9547
receiver loss-of-signal output (LOS) indicates an
absence of input signal.
The MAX9546/MAX9547 operate from a 7.5V to 10V single supply. The differential interface is immune to shortcircuit conditions to an automotive battery (VBAT = 16V),
8
supply (VCC), or ground. These devices include ±15kV
ESD (Human Body Model) protection.
MAX9546
Driver
The MAX9546 driver converts a single-ended video
input into a differential output for transport across a
twisted pair of wires. The input is AC-coupled and the
video signal sync tip is clamped at 3.46V to set the
voltage of the input. The output common-mode voltage
is optimized to reject ground differences between the
MAX9546 and MAX9547 up to ±2V. The differential
gain is internally set to 2V/V to drive a back-terminated
output to unity gain. The maximum input resistance
should not exceed 400Ω to ensure device stability.
_______________________________________________________________________________________
Differential Video Interface Chipset
Common-mode balance is dominated by the gain-bandwidth product at high frequencies and the output resistance at low frequencies; therefore, it is important to
specify CMB over a frequency range. The receiver-side
balance is determined by the common-mode rejection
ratio (CMRR). The CMRR is usually quite large compared
to the CMB; therefore, the CMB is the limiting factor.
Fault Protection and Detection
The MAX9546 fault protection insures the driver outputs
survive a short to any voltage from -2V to +16V and are
ESD-protected to ±15kV HBM. Faults are indicated by
an open-drain fault output (FAULT) being asserted low
and requires a pullup resistor from FAULT to VCC.
MAX9547
Receiver
The MAX9547 receiver is a differential-to-single-ended
converter that removes any common-mode input. The
unique architecture allows the signal gain to be set by
a ratio of two impedances: the user-selected transconductance element or network (ZZT), and an output load
resistance, RL. The gain is set by a fixed internal current gain (K) and the ratio of ZZT and RL. The ZT terminals can be bridged with a complex impedance to
provide lead-lag compensation.
The output is essentially a voltage-controlled current
source as shown in Figure 1. The MAX9547 output is a
current proportional to the differential input voltage, and
inversely proportional to the impedance of the userselected transconductance network, ZZT. The current
output provides inherent short-circuit protection for the
output terminal. A differential input voltage applied to the
input terminals causes current to flow in the transconductance element (ZZT), which is equal to VIN / ZZT. This current in the transconductance element is multiplied by the
preset current gain (K) and appears on the output terminal as a current equal to (K) x (VIN / ZZT). This current
flows through the load impedance to produce an output
voltage according to the following equation:
IN+
1
+
IOUT
7
VIN
IN-
4
VIN
K
ZZT
Figure 1. Operational Mode
⎛ V ⎞
VOUT = K⎜ IN ⎟ RL
⎝ Z ZT ⎠
where K = current-gain ratio (K = 1 for MAX9547), RL =
output load impedance, ZZT = transconductance element impedance, VIN = differential input voltage.
Loss-of-Signal
The receiver includes an LOS output to indicate a signal by detecting the presence of H-Sync. This allows
the MAX9547 to be used with monochrome or color
video. LOS is an open-drain output and requires a
pullup resistor from LOS to VCC.
Setting the Circuit Gain
The MAX9547 produces an output current by multiplying the differential input voltage, VIN, by the transconductance ratio, K (RL / ZZT), where K = 1. The voltage
gain (AV) is set by the impedance of the transconductance network (ZZT) and the output load impedance
(RL) according to the following formula:
⎛ R ⎞
A V = K⎜ L ⎟
⎝ Z ZT ⎠
The factor ZZT is the impedance of the user-selected,
two-terminal transconductance element or network,
connected across the terminals labeled ZT+ and ZT-.
The network Z ZT is selected, along with the output
impedance RL, to provide the desired circuit gain and
frequency shaping.
To maintain linearity, the transconductance network
should also be selected so that current flowing through
it, equal to VIN / ZZT, does not exceed 18mA under
worst-case conditions of maximum input voltage and
minimum transconductance element impedance (ZZT).
Output current should not exceed ±8.8mA except
under fault conditions.
_______________________________________________________________________________________
9
MAX9546/MAX9547
Common-Mode Balance
A driver is typically specified as having a property called
common-mode balance (CMB), longitudinal balance, or
simply line imbalance. Although balance is associated
with the source, it assumes a perfectly balanced, correctly terminated, differential load. Common-mode balance is a measure of the ratio between the differential to
the common-mode output in decibels as shown below.
⎛
⎞
⎜ ( OUT + ) − ( OUT − ) ⎟
CMB = 20Log⎜
⎟
⎜ ( OUT + ) + ( OUT − ) ⎟
⎜
⎟
⎝
⎠
2
MAX9546/MAX9547
Differential Video Interface Chipset
brands entirely. The overall performance of the
MAX9546/MAX9547 is dependent on the choice of the
receiver or transmitter, respectively.
Figure 2 illustrates one possible topology for the
MAX9546 when using other devices with different offset
requirements. Figures 3 and 4 illustrate two possible
topologies for the MAX9547 when using other devices
with unknown or different offset requirements. The circuit shown in Figure 3 has a smaller PCB footprint at
the expense of requiring higher DC offset currents from
the source device. Figure 4 requires no DC offset currents although it has a larger PCB footprint.
Applications Information
Differential Interface
The impedances of the differential interface are made
up of the two source resistors on the driver (MAX9546)
shown as RS and the load resistors on the receiver
(MAX9547) shown as RT in the Typical Application
Circuit. These resistors are chosen so their sum matches the characteristic impedance (Z0) of the differential
transmission line. For example, a Category 5 cable has
a characteristic impedance of 110Ω, so the sum of the
two RS or RT resistors must be 110Ω to correctly drive
the line. To balance the signals they must be equal, so
RS and RT are 55Ω each.
When using the MAX9546 with AC-coupling capacitors,
the FAULT signal will continue to function but only with
respect to a DC short condition. The LOS signal from
the MAX9547 is unaffected by coupling capacitors.
Using Other Transmitters
and Receivers
The MAX9546/MAX9547 are used with other transmitters and receivers; either other MAXIM devices or other
VDD
0.1µF
4.7µF
R1
3.92kΩ
+3.2 VDC OFFSET
D1
3
FAULT
1
8
VCC
VCC
OUT+
U1
7
R2
55Ω
C3
470µF
0V OFFSET
2
R4
75Ω
C4
0.33µF
MAX9546
IN
OUTGND
4
6
GND
5
R3
55Ω
C5
470µF
+3.2 VDC OFFSET
Figure 2. Suggested MAX9546 Configuration for Use with Other Devices
10
______________________________________________________________________________________
TO A DEVICE
OTHER THAN A
MAX9547 USING
CAT5, ETC.
Differential Video Interface Chipset
4.7µF
0.1µF
75Ω
Zt
OPTIONAL EQ NETWORK
FOR LONG CABLE RUNS
2
3
1
0V OFFSET
C3
22µF
4
R3
10kΩ
3.92kΩ
8
ZTP
ZTN
IP
IN
VCC
D1
LED
U1
LOS
MAX9547
IOUT
GND
6
7
75Ω
5
R4
110Ω
TO A DEVICE
OTHER THAN A
MAX9546 USING
CAT5, ETC.
0V OFFSET
R6
10kΩ
C4
22µF
+3.2 VDC OFFSET
3.2V LOW-NOISE REFERENCE
10µF
0.1µF
Figure 3. Suggested MAX9547 Configuration When Using Other Devices
______________________________________________________________________________________
11
MAX9546/MAX9547
+8V
MAX9546/MAX9547
Differential Video Interface Chipset
+8V
0.1µF
75Ω
Zt
OPTIONAL EQ NETWORK
FOR LONG CABLE RUNS
3
1
C3
470µF
R3
51Ω
R805
TO A DEVICE
OTHER THAN A
MAX9546 USING
CAT5, ETC.
0V OFFSET
C4
470µF
3.92kΩ
8
2
0V OFFSET
4.7µF
4
ZTP
ZTN
IP
IN
VCC
D1
LED
U1
LOS
MAX9547
IOUT
6
7
GND
5
R5
51Ω
R805
+3.2 VDC OFFSET
3.2V LOW-NOISE REFERENCE
100µF
0.1µF
Figure 4. Alternate MAX9547 Configuration for Use with Other Devices
12
______________________________________________________________________________________
75Ω
Differential Video Interface Chipset
1000-4-2 Contact Discharge and IEC 1000-4-2 Air-Gap
Discharge (formerly IEC 801-2).
ESD Test Conditions
ESD performance depends on a variety of conditions.
Contact Maxim for a reliability report that documents
test setup, test methodology, and test results.
Human Body Model
Figure 5 shows the Human Body Model, and Figure 6
shows the current waveform it generates when discharged into a low impedance. This model consists of
a 100pF capacitor charged to the ESD voltage of interest, which is then discharged into the test device
through a 1.5kΩ resistor.
RD
1.5kΩ
RC
1MΩ
CHARGE-CURRENTLIMIT RESISTOR
IP 100%
90%
DISCHARGE
RESISTANCE
Ir
PEAK-TO-PEAK RINGING
(NOT DRAWN TO SCALE)
AMPERES
HIGHVOLTAGE
DC
SOURCE
Cs
100pF
STORAGE
CAPACITOR
DEVICE
UNDER
TEST
36.8%
10%
0
0
Figure 5. Human Body ESD Test Model
tRL
TIME
tDL
CURRENT WAVEFORM
Figure 6. Human Body Current Waveform
______________________________________________________________________________________
13
MAX9546/MAX9547
±15kV ESD Protection
As with all Maxim devices, ESD-protection structures
are incorporated on all pins to protect against electrostatic discharges encountered during handling and
assembly. The driver outputs and receiver inputs have
extra protection against static electricity. Maxim’s engineers developed state-of-the-art structures to protect
these pins against ESD of ±15kV without damage. The
ESD structures withstand high ESD in all states: normal
operation and powered down. After an ESD event, the
MAX9546/MAX9547 keep working without latchup. ESD
protection can be tested in various ways; the driver outputs and receiver inputs of this product family are characterized for protection to ±15kV using the Human
Body Model. Other ESD test methodologies include IEC
IEC 1000-4-2
The IEC 1000-4-2 standard covers ESD testing and
performance of finished equipment; it does not specifically refer to integrated circuits (Figure 7).
The major difference between tests done using the
Human Body Model and IEC 1000-4-2 is higher peak
current in IEC 1000-4-2, because series resistance is
lower in the IEC 1000-4-2 model. Hence, the ESD with-
RC
50Ω to 100Ω
stand voltage measured to IEC 1000-4-2 is generally
lower than that measured using the Human Body Model.
Figure 8 shows the current waveform for the ±8kV IEC
1000-4-2 ESD Contact-Discharge test. The Air-Gap test
involves approaching the device with a charged probe.
The Contact-Discharge method connects the probe to
the device before the probe is energized.
I
RD
330Ω
100%
90%
CHARGE-CURRENTLIMIT RESISTOR
HIGHVOLTAGE
DC
SOURCE
Cs
150pF
DISCHARGE
RESISTANCE
STORAGE
CAPACITOR
Figure 7.IEC 1000-4-2 ESD Test Model
DEVICE
UNDER
TEST
IPEAK
MAX9546/MAX9547
Differential Video Interface Chipset
10%
t
tr = 0.7ns TO 1ns
30ns
60ns
Figure 8. IEC 1000-4-2 ESD Generator Current Waveform
14
______________________________________________________________________________________
Differential Video Interface Chipset
7.5V TO 10V
7.5V TO 10V
4.7µF
0.1µF
4.7µF
0.1µF
GND1
GND2
VCC
VCC
VCC
4.7kΩ
4.7kΩ
ZT+
ZZT
75Ω
FAULT
LOS
ZT-
MAX9546
75Ω
CIN
0.33µF
MAX9547
RS
55Ω
OUT+
IN
IN+
VOUT
RS
55Ω
IOUT
OUT-
IN-
75Ω
AC
GND
GND1
GND
RT2
55Ω
RT1
55Ω
RL
75Ω
GND
GND2
CT
1µF TO 47µF
GND1
GND2
GND1
GND2
NOTE: TYPICAL APPLICATION CIRCUIT FOR 110Ω UNSHIELDED (UTP) CABLE
WITH AN OVERALL UNITY GAIN IN A 75Ω VIDEO APPLICATION.
Pin Configurations
TOP VIEW
MAX9547
MAX9546
+
8
VCC
IN+ 1
2
7
OUT+
3
6
OUT-
ZT-
GND 4
5
GND
VCC
1
IN
FAULT
+
8
VCC
ZT+ 2
7
IOUT
3
6
LOS
IN- 4
5
GND
SO-EP
SO-EP
Chip Information
PROCESS: BICMOS
______________________________________________________________________________________
15
MAX9546/MAX9547
Typical Application Circuit
Package Information
(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information
go to www.maxim-ic.com/packages.)
8L, SOIC EXP. PAD.EPS
MAX9546/MAX9547
Differential Video Interface Chipset
PACKAGE OUTLINE
8L SOIC, .150" EXPOSED PAD
21-0111
C
1
1
Revision History
Pages changed at Rev 2: 1, 4, 11, 12
Pages changed at Rev 3: 1, 2, 3, 4, 9–16
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.
16 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600
© 2007 Maxim Integrated Products
is a registered trademark of Maxim Integrated Products, Inc.