MB3800PF-G-BND-JN-EFE1 数据手册
MB3800
Switching Regulator Controller
Description
The MB3800 is a single-channel switching regulator control IC for low voltage applications incorporating a soft start function and short
circuit detection function. The device has a low minimum operating voltage of 1.8 V and is ideal for the power supply of
battery-operated electronic equipment.
Features
■
Wide supply voltage operating range: 1.8 V to 15 V
■
Low current consumption: Typically 5.5 mA in operation, 1 μA or less in stand-by
■
High speed operation is possible: Maximum 1 MHz
■
The error amplifier gain is set inside the IC, so peripheral components are minimized.
■
Incorporates a soft start circuit.
■
Incorporates a timer-latch type short circuit detection circuit (SCP).
■
Totem-pole type output with adjustable on/off current (for NPN transistors)
■
Incorporates a stand-by function.
■
Two types of packages (SOP-8 : 2 types)
Application
■
LCD monitor/panel
■
Power supply module
■
Portable apparatus etc.
Cypress Semiconductor Corporation
Document Number: 002-08716 Rev. *B
•
198 Champion Court
•
San Jose, CA 95134-1709
•
408-943-2600
Revised May 11, 2017
MB3800
Contents
Description ........................................................................ 1
Features ............................................................................. 1
Application ........................................................................ 1
9. Typical Characteristics ............................................... 9
2. Pin Description ............................................................ 3
10. Functional Description ............................................ 12
10.1 Switching Regulator Function ........................... 12
10.2 Power Supply Control Function ........................ 12
10.3 Other Functions ................................................ 13
3. Block Diagram ............................................................. 4
11. Application Example .............................................. 13
4. Absolute Maximum Ratings ....................................... 4
12. Notes On Use ........................................................... 14
1. Pin Assignment ........................................................... 3
5. Recommended Operating Conditions ....................... 5
13. Ordering Information ............................................... 14
6. Electrical Characteristics ............................................ 6
14. RoHS Compliance Information ............................... 14
7. Diagram ....................................................................... 7
15. Package Dimensions ............................................... 15
Document History ........................................................... 17
Sales, Solutions, and Legal Information ...................... 18
8. How to Set the Time Constant for Soft Start and
Short Circuit Detection ................................................ 8
8.1 Soft Start .............................................................. 8
8.2 Short Circuit Protection ........................................ 8
Document Number: 002-08716 Rev. *B
Page 2 of 18
MB3800
1. Pin Assignment
(TOP VIEW)
IN
1
8
FB
SCP
2
7
OSC
VCC
3
6
GND
BR/CTL
4
5
OUT
(SOE008)
(SOB008)
2. Pin Description
Pin No.
Symbol
I/O
1
–IN
I
2
SCP
—
Soft start and SCP setting capacitor connection pin
3
VCC
—
Power supply pin
4
BR/CTL
I
Output current setting and control pin
5
OUT
O
Totem-pole type output pin
6
GND
—
Ground pin
7
OSC
—
Capacitor and resistor connection pin for setting the oscillation frequency
8
FB
O
Error amplifier output pin
Document Number: 002-08716 Rev. *B
Description
Error amplifier inverting input pin
Page 3 of 18
MB3800
3. Block Diagram
V CC
OSC
3
7
Reference
voltage supply
Sawtooth wave
oscillator
0.6 V–
OUT
0.1 V–
5
0.1 V
1.25 V
–IN
1
–
PWM
36 kΩ
+
0.5 V
– Comp.
+
+
+
Error Amp
500 Ω
30 kΩ
Output drive
control circuit
0.3 V
DTC 0.6 V
FB
8
Soft start SCP
6
2
GND
4
SCP
BR/CTL
4. Absolute Maximum Ratings
Parameter
Symbol
Condition
Power supply voltage
VCC
—
Output source current
Output sink current
IO+
IO–
Allowable dissipation
PD
Storage temperature
Rating
Unit
Min
Max
—
16
V
—
–50
mA
—
50
mA
FPT-8P-M01, Ta ≤ +25°C
—
570*
mW
FPT-8P-M02, Ta ≤ +25°C
—
430*
mW
SSOP-8, Ta ≤ +25°C
—
580*
mW
–55
+125
°C
Tstg
—
*: When mounted on a 10 cm square double-sided epoxy board.
WARNING: Semiconductor devices can be permanently damaged by application of stress (voltage, current, temperature, etc.) in
excess of absolute maximum ratings. Do not exceed these ratings.
Document Number: 002-08716 Rev. *B
Page 4 of 18
MB3800
5. Recommended Operating Conditions
(Ta = +25°C)
Parameter
Power supply voltage
Error amplifier input voltage
BR/CTL pin input voltage
Symbol
Value
Unit
Min
Typ
Max
VCC
1.8
—
15
V
VI
–0.2
—
+1.0
V
VBR
–0.2
—
VCC
V
+
Output source current
IO
–40
—
—
mA
Output sink current
IO–
—
—
40
mA
SCP pin capacitance
CPE
—
0.1
—
μF
Phase compensation capacitance
CP
—
0.1
—
μF
Output current setting resistance
RB
150
390
5000
W
Timing resistance
RT
1.0
3.0
10.0
kΩ
Timing capacitance
CT
100
270
10000
pF
fOSC
10
500
1000
kHz
Ta
–30
+25
+85
°C
Oscillation frequency
Operating Ambient temperature
WARNING: The recommended operating conditions are required in order to ensure the normal operation of the semiconductor device.
All of the device’s electrical characteristics are warranted when the device is operated within these ranges.
Always use semiconductor devices within their recommended operating condition ranges. Operation outside these
ranges may adversely affect reliability and could result in device failure.
No warranty is made with respect to uses, operating conditions, or combinations not represented on the data sheet. Users
considering application outside the listed conditions are advised to contact their representatives beforehand.
Document Number: 002-08716 Rev. *B
Page 5 of 18
MB3800
6. Electrical Characteristics
Parameter
Symbol
Condition
VR
—
Circuit to prevent
Reset voltage
malfunction at low input
voltage (U.V.L.O.)
Threshold voltage
VTH
Soft start
Charging current
ICS
Voltage at soft start
completion
VtS
Charging current
ICPC
Threshold voltage
VtPC
Oscillation frequency
fOCS
Short circuit detection
(S.C.P.)
Sawtooth wave oscillator (OSC)
Error amplifier
Idle period adjustment
section
VSCP = 0 V
—
VSCP = 0 V
—
RT = 3.0 kΩ, CT = 270 pF
(VCC = +2 V, Ta = +25°C)
Value
Unit
Min
Typ
Max
—
—
0.9
V
1.1
1.3
1.5
V
–1.5
–1.0
–0.7
μA
0.7
0.8
0.9
V
–1.5
–1.0
–0.7
μA
0.7
0.8
0.9
V
400
500
600
kHz
Frequency input stability
fdV
VCC = 2 V to 15 V
—
2
10
%
Frequency variation with
temperature
fdT
Ta = –30°C to +85°C
—
5
—
%
Input threshold voltage
VT
VFB = 450 mV
480
500
520
mV
VT input stability
VTdV
VCC = 2 V to 15 V
—
5
20
mV
VT variation with
temperature
VTdT
Ta = –30°C to +85°C
—
1
—
%
Input bias current
IB
–1.0
–0.2
+1.0
μA
Voltage gain
AV
70
100
145
V/V
Frequency bandwidth
BW
—
6
—
MHz
0.78
0.87
—
V
—
0.05
0.2
V
—
–40
–24
μA
24
40
—
μA
65
75
85
%
VIN = 0 V
—
AV = 0 dB
+
—
Maximum output voltage
range
VOM
Output source current
VFB = 0.45 V
Output sink current
IOM+
IOM–
Maximum duty cycle
tDUTY
RT = 3.0 kΩ, CT = 270 pF
VFB = 0.8 V
Document Number: 002-08716 Rev. *B
VOM
–
Page 6 of 18
MB3800
Parameter
Output section
Condition
Value
Min
Typ
Max
Unit
VOH1
RB = 390 Ω, IO = –15 mA
1.0
1.2
—
V
VOH2
RB = 750 Ω, VCC = 1.8 V
IO = –10 mA
0.8
1.0
—
V
VOL1
RB = 390 Ω, IO = 15 mA
—
0.1
0.2
V
VOL2
RB = 750 Ω, VCC = 1.8 V
IO = 10 mA
—
0.1
0.2
V
Output source current
IO +
RB = 390 Ω, VO = 0.9 V
—
–30
–20
mA
Output sink current
IO–
RB = 390 Ω, VO = 0.3 V
30
60
—
mA
Pull down resistance
RO
20
30
40
kΩ
Pin voltage
VBR
0.2
0.3
0.4
V
Input off condition
IOFF
–20
—
0
μA
Input on condition
ION
—
—
–45
μA
Pin current range
IBR
–1.8
—
–0.1
mA
Stand-by current
ICCS
BR/CTL pin open or VCC
—
—
1
μA
Average supply current
ICC
RB = 390 Ω
—
5.5
9.3
mA
Output voltage
Output current setting
section/
Control section
Entire device
Symbol
—
RB = 390 Ω
—
7. Diagram
FB pin voltage
Reference input for short circuit
detection comparator
Idle period setting voltage
Sawtooth wave output
Soft start setting voltage
OUT pin waveforms
SCP pin waveforms
Soft start
tS
ON
Power supply control SW
OFF
Document Number: 002-08716 Rev. *B
Output
short
circuit
t PE
Output short circuit
Short circuit
detection
Page 7 of 18
MB3800
8. How to Set the Time Constant for Soft Start and Short Circuit Detection
8.1 Soft Start
At power on, the capacitor CPE connected to the SCP pin (pin 2) starts charging. The PWM comparator compares the soft start setting
voltage as a proportion of the voltage at the SCP pin with the sawtooth waveform.
The comparison controls the ON duty of the OUT pin (pin 5), causing the soft start operation. On completion of soft start operation,
the voltage at the SCP pin stays low, the soft start setting voltage stays high, and the circuit enters the output short circuit detection
wait state.
Soft start time (The time until the output ON duty reaches approximately 50%)
tS [s] ≅ 0.35 × CPE [μF]
8.2 Short Circuit Protection
If the switching regulator output suddenly drops due to load effect, the error amplifier output (FB pin (pin 8)) is fixed at VOM+ and
capacitor CPE starts charging. When the voltage at the SCP pin reaches approximately 0.8 V, the OUT pin (pin 5) is set low and the
SCP pin (pin 2) stays low.
Once the protection circuit operates, the circuit can be restored by resetting the power supply.
• Short circuit detection time
tPE [s] ≅ 0.8 × CPE [μF]
Document Number: 002-08716 Rev. *B
Page 8 of 18
MB3800
9. Typical Characteristics
Input threshold voltage vs. Supply voltage
T a = +25°C
R B = 390 Ω
10
1.0
Input threshold voltage V T (V)
Average supply current I CC (mA)
Average supply current vs. Supply voltage
8
6
4
2
0
0
4
8
12
16
0.8
0.6
0.4
0.2
0
20
T a = +25°C
4
0
Input threshold voltage vs. Supply voltage
0.8
0.6
0.4
0.2
0
High level output voltage V OUT (V)
T a = +25°C
0
1.0
2.0
3.0
4.0
5.0
10
V CC = 2 V
5
0
–5
–10
–15
–40
–20
0
+20
+40
+60
+80
Low level output
1.6
1.2
0.8
0.4
–10
–20
–30
–40
High level output current IOUT (mA)
Document Number: 002-08716 Rev. *B
20
Input threshold voltage variation ratio vs.
Operating ambient temperature
High level output
V CC = 2 V
R B = 390 Ω
T a = +25°C
0
16
Operating ambient temperature T a (°C)
2.0
0
12
Supply voltage V CC (V)
–50
Low level output voltage V OUT (mV)
Input threshold voltage V T (V)
1.0
8
Supply voltage V CC (V)
Input threshold voltage variation ratio ΔV T/V T (%)
Supply voltage V CC (V)
+100
V CC = 2 V
R B = 390 Ω
T a = +25°C
500
400
300
200
100
0
0
20
40
60
80
100
Low level output current IOUT (mA)
Page 9 of 18
MB3800
-50
-40
V CC = 2 V
V OUT = 0.9 V
T a = +25°C
-30
-20
-10
0
-0.4
0
-0.8
-1.2
-1.6
BR/CTL pin input voltage vs. BR/CTL pin input current
BR/CTL pin input voltage V BR (mV)
Output source current IOUT (mA)
Output source current vs. BR/CTL pin input current
500
400
300
200
100
0
-2.0
V CC = 2 V
T a = +25°C
0
BR/CTL pin input current I BR (mA)
-0.4
-0.8
-1.2
-1.6
-2.0
BR/CTL pin input current I BR (mA)
Oscillation frequency vs.Timing resistor
Average supply current vs. BR/CTL pin input current
5.0
V CC = 2 V
T a = +25°C
Oscillation frequency f OSC (Hz)
Average supply current I CC (mA)
1M
4.0
3.0
2.0
1.0
0
-20
0
-40
-60
-80
500 k
200 k
100 k
C T = 1000 pF
50 k
20 k
C T = 10000 pF
10 k
5k
2k
10 k
5k
20 k
Timing resistor R T (Ω)
Frequency variation ratio vs. Operating ambient temperature
Frequency variation ratio vs. Supply voltage
10
10
C T = 270 pF
R T = 3.0 kΩ
Ta = +25°C
5
Frequency variation ratio Δf/f (%)
Frequency variation ratio Δf/f (%)
2k
1k
-100
BR/CTL pin input current I BR (μA)
0
-5
-10
-15
V CC = 2 V
T a = +25°C
C T = 100 pF
0
2
4
6
8
10
12
Supply voltage V CC (V)
Document Number: 002-08716 Rev. *B
14
16
V CC = 2 V
C T = 270 pF
R T = 3.0 kΩ
5
0
-5
-10
-15
-40
-20
0
+20
+40
+60
+80 +100
Operating ambient temperature T a (°C)
Page 10 of 18
MB3800
Maximum duty cycle vs. Oscillation frequency
V CC = 2 V
C T = 270 pF
Ta = +25°C
Maximum duty cycle t DUTY (%)
100
80
60
40
20
0
10 k
100 k
1M
Oscillation frequency f OSC (Hz)
Output pin voltage and current waveforms
(reference data)
2V
(V)
6
V CC = 2 V
C T = 270 pF
R T = 1.0 kΩ
4
V OUT
2
0
(mA)
50
I OUT
0
–50
10 mV
0
200 ns
0.4
0.8
1.2
1.6
2.0 t(μs)
Note: The OFF delay time of V OUT depends on the
characteristics of the external transistor.
Measurement circuit diagram
V CC
(5 V)
22 μH
18 kΩ
MB3800
5
I OUT
+
V OUT 10 μF
4
2 kΩ
390 Ω
–IN
Document Number: 002-08716 Rev. *B
Page 11 of 18
MB3800
10. Functional Description
10.1 Switching Regulator Function
10.1.1 Reference voltage circuit
The reference voltage circuit generates a temperature-compensated reference voltage (≅1.25V) from voltage supplied from the VCC
pin (pin 3). In addition to providing the reference voltage for the switching regulator, the circuit also sets the idle period.
10.1.2 Sawtooth wave oscillator
The sawtooth oscillator generates a sawtooth wave (up to 1 MHz) that is stable with respect to the supply voltage and temperature.
The capacitor and resistor that set the oscillation frequency are connected to the OSC pin (pin 7).
10.1.3 Error amplifier (Error Amp)
The error amplifier detects the output voltage of the switching regulator and outputs the PWM control signal. The voltage gain is fixed,
and connecting a phase compensation capacitor to the FB pin (pin 8) provides stable phase compensation for the system.
10.1.4 PWM comparator (PWM Comp.)
The voltage comparator has one inverting and three non-inverting inputs. The comparator is a voltage/pulse width converter that
controls the ON time of the output pulse depending on the input voltage. The output level is high (H) when the sawtooth wave is lower
than the error amplifier output voltage, soft start setting voltage, and idle period setting voltage.
10.1.5 Output circuit
The output circuit has a totem pole type configuration and can drive an external NPN transistor directly. The value of the ON/OFF
current can be set by a resistor connected to the BR/CTL pin (pin 4).
10.2 Power Supply Control Function
Stand-by mode (supply current 1 μA or less) can be set by connecting the BR/CTL pin (pin 4) to VCC or by making the pin open circuit.
SW
Mode
OFF
Stand-by mode
ON
Operating mode
MB3800
4
BR/CTL
RB
SW
Document Number: 002-08716 Rev. *B
Page 12 of 18
MB3800
10.3 Other Functions
10.3.1 Soft start and short circuit detection
Soft start operation is set by connecting capacitor CPE to the SCP pin (pin 2). Soft start prevents a current spike on start-up.
On completion of soft start operation, the SCP pin (pin 2) stays low and enters the short circuit detection wait state. When an
output short circuit occurs, the error amplifier output is fixed at VOM+ and capacitor CPE starts charging. After charging to
approximately 0.8 V, the OUT pin (pin 5) is set low and the SCP pin (pin 2) stays low.
Once the protection circuit operates, the circuit can be restored by resetting the power supply. (See “How to Set the Time
Constant for Soft Start and Short Circuit Detection”.)
10.3.2 Circuit to prevent malfunction at low input voltage
Transients when powering on or instantaneous glitches in the supply voltage can lead to malfunction of the control IC and cause
system damage or failure. The circuit to prevent malfunction at low input voltage detects a low input voltage by comparing the
supply voltage to the internal reference voltage. On detection, the circuit fixes the OUT pin (pin 5) to low.
The system recovers when the supply voltage rises back above the threshold voltage of the malfunction prevention circuit.
11. Application Example
18 kΩ
22 μH
ÐIN
SCP
V in
(3 V)
1
8
2
7
FB
OSC
+
MB3800
+
V CC
3
6
BR/CTL
4
0.1 μF
5
33 μF
390 Ω
2 kΩ
Vo
(5 V)
GND
10 μF
OUT
0.1 μF
270 pF
3 kΩ
CTL
Document Number: 002-08716 Rev. *B
Page 13 of 18
MB3800
12. Notes On Use
■
■
Take account of common impedance when designing the earth line on a printed wiring board.
Take measures against static electricity.
For semiconductors, use antistatic or conductive containers.
❐ When storing or carrying a printed circuit board after chip mounting, put it in a conductive bag or container.
❐ The work table, tools and measuring instruments must be grounded.
❐ The worker must put on a grounding device containing 250 kΩ to 1 MΩ resistors in series.
❐
■
Do not apply a negative voltage
Applying a negative voltage of −0.3 V or less to an LSI may generate a parasitic transistor, resulting in
malfunction.
❐
13. Ordering Information
Part Number
Package
Remarks
MB3800PF-❏❏❏E1
8-pin Plastic SOP
(SOE008)
–
MB3800PNF-❏❏❏E1
8-pin Plastic SOP
(SOB008)
–
14. RoHS Compliance Information
The LSI products of Cypress with “E1” are compliant with RoHS Directive , and has observed the standard of lead, cadmium,
mercury, Hexavalent chromium, polybrominated biphenyls (PBB) , and polybrominated diphenyl ethers (PBDE) .
The product that conforms to this standard is added “E1” at the end of the part number.
Document Number: 002-08716 Rev. *B
Page 14 of 18
MB3800
15. Package Dimensions
Package Code: SOE008
b
0.39
0.47
0.55
L
0.45
0.60
0.75
b
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Document Number: 002-08716 Rev. *B
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