Bay Linear
Inspire the Linear Power
Switching Regulator Controller
Step Up Low Voltage (BIPOLAR)
Description
The Bay Linear B3800 series is monolithic control circuit
containing the primary functions required for DC-to-DC
converters. This device is design for low voltage applications
incorporating a soft start function and sort circuit detection
function. The device has a low minimum operating voltage of
1.8V and is ideal for the power supply of battery-operated
electronic equipments.
This series was specially designed to be incorporated in StepDown and voltage-inverting applications with a minimum
number of external components.
The B3800 is offer in 8-pin DIP or Surface mount package.
Pin Connection
8-Pin Su rface Mount
8-
8-Pin Su rface Mount
8-
-IN
-IN
SCP 2
SCP 2
1
1
1
1
2
2
8
8
8
8
FB
FB
7
7
7
7
OSC
OSC
BR/CTL
BR/CTL
Vcc
Vcc
3
3
3
3
4
4
4
4
6
6
6
6
GND
GND
5
5
5
5
OUT
OUT
Features
• Wide operation from…………... 1.8 to 15V
• Low Standby Current……………….. 1 µA
• Low Current Consumption……… 5.5mA
• high Speed Operation ……………. 1MHz
Incorporates soft start circuit
•
•
Incorporates a stand-by function
Incorporate a times-latch short circuit
•
detection circuit (SCP)
• Totem-pole type output with adjustable
on/off current (for NPN transistor)
• The error amplifier gain is set inside the
IC, so peripheral components are
minimized.
• Direct Replacement for MB3800
Applications
• Digital Camera
• MP3
• Low Battery Operating Applications
Ordering Information
SO-8
8-pin
B3800M B3800P
P-DIP
8-pin
Operating
Temp. Range
-40°C to 85°C
B3800
Bay Linear, Inc
To p V i e w
To p V i e w
2418 Armstrong Street, Livermore, CA 94550 Tel: (925) 606-5950, Fax: (925) 940-9556 www.baylinear.com
B3800
PIN Description
Pin No. Symbol I/O Description
1 -IN I
2 SCP 3 V
CC
4 BR/CTL I
5 V
OUT
6 GND 7 OSC 8 FB O
Error amplifier inverting
Soft start and SCP setting capacitor connection pin
Power supply pin
-
Output current setting and control pin
Totem-pole type output pin
O
Ground pin
Capacitor and resistor connection pin setting the oscillation frequency
Error amplifier output pin
Absolute Maximum Rating
Parameter Symbol Value Unit
Supply Voltage V
Output source current I
Output sink current I
Allowable dissipation
Operating temperature T
Storage temperature Tstg -55 to +125
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.
SOP-8, Ta≤+25°C
SOP-8, T
SSOP-8, T
CC
+
O
-
O
≤+25°C
a
≤+25°C 580 mW
a
op
16 V
-50 mA
50 mA
570 mW
430 mW
-30 to +85
°C
°C
Recommended Operating Condition
Parameter Symbol
Power Supply Voltage V
Error amplifier input voltage V
BR/CTL pin input voltage V
Output source current I
Output sink current I
SCP pin capacitance C
Phase compensation capacitance C
Output current setting resistance
Timing resistance
Timing Capacitance C
Oscillation frequency f
Operation temperature
WARNING: Recommended operating conditions are normal operating ranges for the semiconductor device. All the device’s
electrical characteristics are warranted when operated within these ranges. Always use semiconductor devices within the
recommended operating conditions. 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 Bay Linear.
R
R
OSC
T
CC
I
BR
+
O
-
O
PE
P
B
T
T
OP
Min Typ. Max.
1.8 - 15 V
-.0.2 - 1.0 V
-0.2 - V
-40 - - mA
- - 40 mA
- 0.1 - µF
- 0.1 - µF
150 390 5000
1.0 3.0 10.0
100 270 10000 pF
10 500 1000 kHz
-30 +30 +85
Values
CC
Unit
V
Ω
kΩ
°C
Bay Linear, Inc
2418 Armstrong Street, Livermore, CA 94550 Tel: (925) 606-5950, Fax: (925) 940-9556 www.baylinear.com
Electrical Characteristics
Parameter Symbol Conditions
Circuit to Prevent
Malfunction at low input
voltage (U.V.L.O.)
Soft Start
(OSC)
Sawtooth wave oscillator
(OSC)
Error amplifier
Idle period adjustable
section
Output section
Output current setting
section/ Control section
Entire device
Reset Voltage V
Threshold voltage
Changing current
Voltage at soft start
completion
Charging current I
Threshold voltage V
Oscillation freq. f
Frequency input
stability
Frequency variation
with temperature
Input threshold
voltage
VTinput stability V
VT variation with
temperature
Input bias current I
Voltage gain
Frequency bandwidth
Maximum output
voltage range
Output source current I
Output sink current I
Maximum duty cycle
Output voltage
Output source current I
Output sink current I
Pull down resistance R
Pin Voltage V
Input off condition I
Input on condition I
Pin current range I
Stand-by current I
Average supply
current
Value
B3800
Unit
Min. Typ. Max.
R
V
TH
I
CS
V
TS
cpc
PC
ocs
f
dv
f
dt
V
T
Tdv
V
TDT
B
A
V
BW A
+
V
OM
-
V
OM
+
OM
_
OM
t
DUTY
V
OH1
V
OH2
V
OL1
V
OL2
+
O
-
O
O
BR
OFF
ON
BR
CCB
I
CC
-
V
=0V 0.7 0.8 0.9 V
SCP
V
=0V -1.5 -1.0 -0.7 µA Short Circuit detection
SCP
- 0.7 0.8 0.9 V
RT=3.0kΩ, CT=270pF
VCC=2V to 15V - 2 10 %
Ta=-30°C to +85°C
VFB=450mV 480 500 520 mV
VCC= 2V to 15V - 5 20 mV
Ta= -30°C to +85°C
VIN=0V -1.0 -0.2 1.0 µA
- 70 100 145
=0dB - 6 -
V
-
VFB=0.45V
RT=3.0kΩ, CT=270pF
V
=0.8V
FB
RB=390Ω, IO= -15mA
RB=750Ω, IO= -10mA,
=1.8V
V
CC
RB=390Ω, IO=15mA
RB=750Ω, IO=10mA,
V
=1.8V
CC
RB=390Ω, VCC=0.9V
RB=390Ω, VCC=0.3V
- 20 30 40
RB=390Ω,
-
BR/CTL pin open or
V
cc
RB=390Ω,
- - 0.9 V
1.1 1.3 1.5 V
-1.5 -1.0 -0.7 µA
400 500 600
kH
z
- 5 - %
- 1 - %
V/
V
M
Hz
0.78 - 0.87
0.05
-
0.2
V
- -40 -24 µA
24 40 - µA
65 75 85 %
1.0 1.2 - V
0.8 1.0 - V
- 0.1 0.2 V
- 0.1 0.2 V
- -30 -20 mA
30 60 - mA
kΩ
0.2 0.3 0.4 V
-20 - 0 µA
- - -45 µA
-1.8 - -0.1 mA
- - 1 mA
- 5.5 9.3 mA
Bay Linear, Inc
2418 Armstrong Street, Livermore, CA 94550 Tel: (925) 606-5950, Fax: (925) 940-9556 www.baylinear.com