MIC9131
Micrel, Inc.
MIC9131
High-Voltage, High-Speed Telecom
DC-to-DC Controller
General Description
The MIC9131 is a current-mode PWM controller that efficiently
converts –48V telecom voltages to logic levels. The MIC9131
features a high voltage start-up circuit that allows the device to
be connected to input voltages as high as 180V. The high input
voltage capability protects the MIC9131 from line transients
that are common in telecom systems. The start-up circuitry
also saves valuable board space and simplifies designs by
integrating several external components.
The MIC9131 is capable of high speed operation. Typically
the MIC9131 can control a sub-25ns pulse width on the gate
out pin. Its internal oscillator can operate over 2.5MHz, with
even higher frequencies available through synchronisation.
The high speed operation of the MIC9131 is made safe by
the very fast, 34ns response from current sense to output,
minimizing power dissipation in a fault condition.
The MIC9131 allows for the designs of high efficiency power
supplies. It can achieve efficiencies over 90% at high output
currents. Its low 1.3mA quiescent current allows high efficiency
even at light loads.
The MIC9131 has a maximum duty cycle of 75%. For designs
requiring a maximum duty cycle of 50%, refer to the MIC9130.
The MIC9131 is available in a 16-pin SOP and 16-pin QSOP
package options. The junction temperature range is from
–40°C to +125°C.
Features
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Input voltages up to 180V
Internal oscillator capable of > 2.5MHz operation
Accurate 75% maximum duty cycle
Synchronisation capability to 6MHz
Current sense delay of 34ns
Minimum pulse width of <25ns
90% efficiency
1.3mA quiescent current
1µA shutdown current
Soft-start
Resistor programmable current sense threshold
Selectable soft-start retry
4Ω sink, 12Ω source output driver
Programmable under-voltage lockout
Constant-frequency PWM current-mode control
16-pin SOIC and 16-pin QSOP
Telecom power supplies
Line cards
ISDN network terminators
Micro- and pico-cell base stations
Low power (< 100W) dc-dc converters
DSL line cards
Applications
Typical Application
VIN
36V to 72V
1MΩ
0.1µF
12V
10Ω
10µF
25V
1N5818
4:1
6:1
L = 530µH
VOUT
3.3V @ 20A
Si4884DY½
(x2)
B320A
1.5µH
100µF
37.4kΩ
13
1
2
10
UVLO
LINE
VCC
7
FB
COMP
RBIAS
SS
CPWR
VBIAS
MIC9131
EN
Si4884DY½
(x2)
10kΩ
6
3
12
8
OUT
16
SLOPE
COMPENSATION
IRFS3IN20D
ISNS
14
8.2kΩ
562kΩ
0.1µF
9
OSC
SYNC
AGND PGND
4
5
0.1Ω
1W
11
15
10nF
2.61kΩ
270pF
OPTO
FEEDBACK
90% Efficient Telecommunications Power Supply
Micrel, Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com
August 2006
1
M9999-080206
MIC9131
Micrel, Inc.
Part Number
Max. Duty Cycle
75%
75%
Junction Temp. Range
-40°C to +125°C
-40°C to +125°C
Package
16-Pin SOP
16-Pin QSOP
Ordering Information
Standard
MIC9131BM
MIC9131BQS
Pb-Free
MIC9131YM
MIC9131YQS
Pin Configuration
LINE 1
VCC 2
16 OUT
15 PGND
14 ISNS
13 UVLO
12 SS
11 AGND
RBIAS 3
OSC 4
SYNC 5
COMP 6
FB 7
10 EN
9 VBIAS
CPWR 8
16-Pin SOP (M)
16-Pin QSOP (QS)
Pin Description
Pin Number
1
2
3
4
5
6
7
8
Pin Name
LINE
VCC
RBIAS
OSC
SYNC
COMP
FB
CPWR
Pin Function
Line (Input): 180Vdc maximum supply input. May be floated if unused.
Supply (Input): MIC9131 internal supply input.
Bias Resistor (External Component): Connect 562KΩ to ground.
Oscillator RC Network (External Components): Connect external resistor-ca-
pacitor network to set oscillator frequency.
Synchronization (Input): External oscillator input for slave operation of con-
troller. See OSC. Do not float.
Compensation (External Components): Error amplifier output for external
compensation network connection.
Feedback (Input): Error amplifier inverting input.
Current Limit Selection (Input): When CPWR is high, an over-current condi-
tion at the ISNS input will terminate the gate drive and reset the soft-start
latch. If the CPWR pin is low, an over-current condition at the ISNS input
will terminate the gate drive signal, but will not cause a reset of the soft-start
circuit.
Reference (Output): Internal 5V supply. Will source 5mA maximum.
Enable (Input): Logic level enable/shutdown input; logic high = enabled (on),
logic low = shutdown (off).
Analog Ground (Return)
Soft-Start (External Components): Connect external capacitor to slowly ramp
up duty cycle during startup and over-current conditions.
Undervoltage Lockout (External Components): Connect to unbiased resistive
divider network to set controller’s minimum operating voltage. Connect to
VBIAS if not needed.
Current Sense (Input): Connect between external switching MOSFET source
and switch current sense resistor.
Power Ground (Return)
Switch Drive Output (Output): Connect to gate of external switching MOS-
FET.
9
10
11
12
13
VBIAS
EN
AGND
SS
UVLO
14
15
16
ISNS
PGND
OUT
M9999-080206
2
August 2006
MIC9131
Micrel, Inc.
Absolute Maximum Ratings
(Note 1)
Line Input Voltage (V
LINE
) ......................................... +190V
V
CC
Input Voltage (V
CC
) .............................................. +19V
Current Sense Input Voltage (V
ISNS
) .............. –0.3 to +5.3V
Enable Voltage (V
EN
) ............................ –0.3 to V
CC
+ 0.3V
Feedback Input Voltage (V
FB
) ........................ –0.3 to +5.3V
Sync Input Voltage (V
SYNC
) ............................ –0.3 to +5.3V
Soft-Start Voltage (V
SS
) .................................. –0.3 to +5.3V
UVLO Voltage (V
UVLO
) ................................... –0.3 to +5.3V
Storage Temperature (T
S
) ........................ –65°C to +150°C
Power Dissipation (P
D
) ........................................................
16-pin SOP ...................................400mW @ T
A
= +85°C
16-pin QSOP ................................245mW @ T
A
= +85°C
ESD Rating,
Note 3
Operating Ratings
(Note 2)
Line Input Voltage (V
LINE
) .................V
CC
to +180V,
Note 4
V
CC
Input Voltage (V
CC
) .................................. +9V to +18V
Junction Temperature Range (T
J
) ............ –40°C to +125°C
Package Thermal Resistance
16-pin SOP
(θ
JA
) .............................................. 100°C/W
16-pin QSOP
(θ
JA
) ............................................ 163°C/W
Electrical Characteristics
T
A
= 25°C, V
LINE
= 48V, V
CC
= 10V, R
t
= 9.47KΩ, C
t
= 470pF, R
BIAS
= 562kΩ, V
EN
= 10V, V
ISNS
= 0V, V
UVLO
= 2V
,
V
SYNC
= 0V, unless
otherwise noted.
Bold
values indicate –40 °C ≤T
J
≤ +125°C.
Parameter
Condition
Min
4.7
4.6
24
5
180
200
f
OSC/4
75
2.5
100
6
2.5
0.7
50
V
COMP
= V
FB
2.475
2.45
2.5
90
4
9V ≤ V
CC
≤ 18V
60
80
1
3.5
100
2.5
115
4
160
1.5
1.5
300
V
FB
= 2.7V; V
COMP
= 5V
V
FB
= 2.7V; I
COMP
= –50µA
V
FB
= V
COMP
V
FB
= 2.3V; V
COMP
= 0V
2.525
2.55
MHz
V
V
ns
V
dB
MHz
dB
µA
mA
mV
V
nA
V/µs
V/µs
Typ
Max
5.0
5.1
40
30
220
Bias Regulator
Output Voltage
Line Regulation
Load Regulation
Oscillator Section
Initial Accuracy (f
OSC
)
Maximum Duty Cycle
Voltage Stability (Δf/f)
Temperature Stability
ppm/°C
Maximum Sync Frequency
Sync Threshold Level
Sync Hysteresis
Sync Minimum Pulse Width
Error Amp Section
FB Voltage
Open Loop Voltage Gain, A
VOL
Unity Gain Bandwidth
PSRR
COMP Sink Current
COMP Source Current
V
COMP
Low
V
COMP
High
Slew Rate
9V ≤ V
CC
≤18V
–40°C ≤ T
J
≤ 125°C
Note 5
Oscillator Output Frequency
I
VBIAS
= 0mA; V
OSC
= 0V (Oscillator OFF)
9V ≤ V
CC
≤18V, I
VBIAS
= 0mA; V
OSC
= 0V
0mA ≤ I
VBIAS
≤ 5mA; V
OSC
= 0V
R
t
= 9.47KΩ, C
t
= 470pF
4.85
V
V
mV
mV
kHz
kHz
%
%
Units
Input Bias Current (I
FB
)
V
FB
= 2.3V; I
COMP
= +500µA
SINK
SOURCE
August 2006
3
M9999-080206
MIC9131
Parameter
Preregulator
Input Leakage Current
V
CC
Gate Lockout (V
GLO(ON)
)
V
CC
Gate Lockout Hysteresis
(ΔV
GLO
)
V
LINE
= 48V
V
LINE
= 180V, V
CC
= 10V
V
LINE
= 48V
0.1
7.2
700
7.7
500
9
7.5
800
V
GLO(ON)
Micrel, Inc.
Condition
Min
Typ
Max
10
Units
µA
V
mV
V
mV
mA
1.3
10
10
0.888
50
2.2
+1
1.6
2.5
1.16
4
1.22
140
145
25
V
ISNS
= 5V
0
8
4
12
8
12
6
6
1.28
mA
µA
µA
V
ns
µA
V
mV
µA
V
µA
V
mV
°C
°C
ns
Ω
Ω
ns
ns
V
CC
Pre-Regulator Off (V
PR(OFF)
)
V
CC
Pre-Regulator Hysteresis
(ΔV
PR
)
Start-up Current
Supply
Supply Current, I
VCC
Enable Input Current
Shutdown Supply Current
Protection and Control
Current Limit Threshold Voltage
Current Limit Delay to Output
Current Limit Source Current
Enable Input Threshold (Turn-on)
Enable Input Hysteresis
CPWR Input Current
CPWR Threshold
Soft-Start Current
Line UVLO Threshold (Turn-on)
Line UVLO Threshold Hysteresis
Thermal Shutdown
Thermal Shutdown Hysteresis
MOSFET Driver
Output Minimum On-Time
Output Driver Impedance
Rise Time
Fall Time
Note 1.
Note 2.
Note 3.
Note 4.
Note 5.
V
LINE
= 48V
V
LINE
= 48V
V
LINE
= 48V, V
CC
= 7.5V,
Note 4
Pin 16 (OUT) = OPEN
V
EN
= 0V ,10V; V
LINE
= 48V
V
EN
= 0V ; V
CC
= 18V
+0.5V
700
12
1
–10
0.1
0.1
0.772
V
ISNS
= 0V to 5V
V
ISNS
= 0V
30
1
–1
0.83
34
40
1.6
150
V
CPWR
= 5V, 0V
V
SS
= 0V
SINK ; I
SINK
= 200mA
C
OUT
= 500pF
C
OUT
= 500pF
SOURCE ; I
SOURCE
= 200mA
Exceeding the absolute maximum rating may damage the device.
The device is not guaranteed to function outside its operating rating.
Devices are ESD sensitive. Handling precautions recommended.
If a substained DC voltage >150V is applied to the LINE pin, a current-limiting 1.8kΩresistor should be used in series with the LINE pin. This
condition does not apply for transient conditions over 150V.
For oscil½
tions of the internal 5V regulator. See
Applications Information
for details.
-
M9999-080206
4
August 2006
MIC9131
Micrel, Inc.
Typical Characteristics
Oscillator Frequency
vs. V
CC
Voltage
OSC FREQ. VARIATION (%)
0.3
OSC FREQ. VARIATION (%)
2
1.5
1
0.5
0
-0.5
-1
-1.5
-2
-2.5
-40
Oscillator Frequency
vs. Temperature
V
C C
= 10V
R
B IAS
= 560K
R = 9.47K
t
C = 470pF
t
2.502
REFERENCE VOLTAGE (V)
Error Amp Reference Voltage
vs. V
CC
Voltage
R
B IAS
= 560K
0.2
0.1
0.0
-0
F
OSC (NOM)
=200kHz
Rt=9.47K
2.501
-0.2
-0.3
-0.4
2.500
Ct=470pF
-0.5
8 9 10 11 12 13 14 15 16 17 18
V
CC
(V)
0
40
80
120
TEMPERATURE (°C)
160
2.499
8 9 10 11 12 13 14 15 16 17 18
V
CC
(V)
2.510
REFERENCE VOLTAGE (V)
Error Amp Reference Voltage
vs. Temperature
V
C C
= 10V
1.220
1.215
THRESHOLD (V)
Line UVLO Threshold
vs. V
CC
1.24
UVLO THRESHOLD (V)
Line UVLO Threshold
vs. Temperature
V
C C
=10V
R
B IAS
=560K
2.505
R
B IAS
= 560K
2.500
2.495
2.490
2.485
2.480
-40 -20 0 20 40 60 80 100120140
TEMPERATURE (°C)
1.210
1.205
1.200
1.195
1.190
1.185
1.180
8 9 10 11 12 13 14 15 16 17 18
V
CC
(V)
1.23
1.22
1.21
1.2
1.19
1.18
-40
0
40
80
120
TEMPERATURE (°C)
160
2.4
QUIESCENT CURRENT (mA)
Quiescent Current
vs. V
CC
Voltage
R = 9.47K
t
Ct = 470pF
B IAS
1.5
QUIESCENT CURRENT (mA)
Quiescent Current
vs. Temperature
QUIESCENT CURRENT (mA)
2.2
2.0
1.8
1.6
1.4
1.2
1.0
8
R
= 560K
1.48
1.46
1.44
1.42
1.4
1.38
1.36
1.34
1.32
V
C C
= 10V
R
B IAS
= 560K
R = 9.47K
t
Ct = 470pF
10
9
8
7
6
5
4
3
2
1
0
Quiescent Current
vs. Frequency
Ct = 470pF
C = 100pF
t
300
350
400
450
500
2000
3.5
QUIESCENT CURRENT (mA)
Quiescent Current
vs. R
BIAS
V
C C
= 10V
R = 9.53K
t
Ct = 470pf
ISNS to Gate Output Delay
vs. R
BIAS
90
80
70
DELAY (ns)
DELAY (ns)
60
50
40
30
20
10
0
0
200
180
160
140
120
ISNS to Gate Output Delay
vs. Overdrive
R
B IAS
=160K
3
2.5
2
f
OSC
= 200kHz
1.5
1
0
200 400 600 800 1000 1200
R
BIAS
(kΩ)
100
80
60
40
20
0
0
200
400
600
800
1000
1200
1400
OVERDRIVE (mV)
August 2006
5
1600
1800
0.5
200 400 600 800 1000 1200
R
BIAS
(kΩ)
0
50
100
150
200
250
10
12
14
V
CC
(V)
16
18
1.3
-40 -20 0 20 40 60 80 100120140
TEMPERATURE (°C)
GATE DRIVE FREQUENCY (kHz)
R
B IAS
=560K
R
B IAS
=360K
M9999-080206
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