BF1210 Series
BYD Microelectronics Co., Ltd.
PWM/PFM Control
Step-Down DC/DC Converter
GENERAL DESCRIPTION
The BF1210 series is a step-down DC/DC converter with
PWM/PFM control. It contains oscillation circuit, error
amplifier, voltage reference, soft-start circuit, etc. The
soft-start circuit is used to prevent inrush current at start-up.
The BF1210 series has the characteristics of low ripple and
high efficiency. It works with PWM/PFM control, and can
switch automatically between them. Normally, it operates
with the PWM control mode, which gets a steady output
voltage by adjusting the duty cycle of control pulse. Under
light load, it switches PWM to PFM mode automatically.
While at heavy load, it will keep working with a high duty
cycle. This working mode ensures high efficiency over a
wide range.
With the addition of a P-channel MOSFET, an inductor,
capacitors, and a diode connected externally, the BF1210
can work as a step-down DC/DC converter. It is available in
SOT23-5 package, and serves as an ideal power
management unit for many devices.
FEATURES
4V to 16 V wide input voltage range
5V/3.3V output voltage
450KHz constant operation frequency
PWM/PFM switching control mode
Soft-start function
APPLICATIONS
On-board power supplies of battery devices for PDAs,
portable telephones and electronic notebooks.
Fixed voltage power supply for digital cameras, video
and communication equipment.
Power supplies for PDVDs and microcomputers
Applied to two lithium-ion cells power system
Conversion of AC adapter input to 5V/3.3V
TYPICAL APPLICATION
VIN
PMOS
22uH
VOUT
VIN
VIN
CIN
10uF
EN
MOSG
VOUT
COUT
22uF
BF1210
EN
GND
Datasheet
ES-BYD-WDZCE07D-001
Rev.A/1
Page 1 of 10
BYD Microelectronics Co., Ltd.
BF1210 Series
PIN CONFIGURATION
MOSG
VIN
GND
EN
VOUT
PIN DEFINITION
PIN
1
2
3
4
5
NAME
EN
GND
VOUT
MOSG
VIN
DESCRIPTION
On/Off control pin
Ground
Output voltage monitoring pin
Connection pin for external MOSFET
Power
PRODUCT NAME STRUCTURE
PRODUCT NAME
PRODUCT NAME DESCRIPTION
Part Number
Top Mark
BF1210Y50
DAAYW
BF1210Y33
DABYW
BF1210Y
DACYW
*Note: Y=Manufacturing Year Code
W=Manufacturing Week Code
Package Type
SOT23-5
SOT23-5
SOT23-5
Output Voltage
5V
3.3V
Adjustable(3V-5.5V)
Datasheet
ES-BYD-WDZCE07D-001
Rev.A/1
Page 2 of 10
BYD Microelectronics Co., Ltd.
BF1210 Series
(T
A
= 25°C, unless otherwise noted)
ELECTRICAL CHARACTERISTICS
SYMBOL
V
IN
V
OUT
(E)
I
Q
I
SHUT
the output current
of MOSG pin
PARAMETER
Input voltage
Output voltage
Static current
Shutdown current
I
MOSGH
I
MOSGL
Line regulation
CONDITIONS
V
OUT
(S)=5V
V
OUT
(S)=3.3V
---
EN=1
,
no-load
EN=0
V
IN
=7.4V、V
MOSG
=V
IN
-0.4V
V
IN
=7.4V、V
MOSG
=0.4V
V
IN
=10~14V、load current=1A
,
V
OUT
(S)=5V
V
IN
=8~12V、load current=1A
,
V
OUT
(S)=3.3V
V
IN
=10V、load current=0~2A
,
V
OUT
(S)=5V
V
IN
=8V、load current=0~2A
,
V
OUT
(S)=3.3V
---
V
OUT
(S)=5V
V
OUT
(S)=3.3V
V
IN
=10V
V
IN
=10V
V
IN
=10V、load current=1A
,
V
OUT
(S)=5V
V
IN
=8V、load current=1A
,
V
OUT
(S)=3.3V
V
OUT
(S)=5V
V
OUT
(S)=3.3V
MIN
5.5
4
V
OUT
(S)
x0.976
---
---
-8
+16
---
---
---
---
---
1
0.8
7
---
---
---
---
---
TYPICAL MAX UNITS
---
16
---
16
V
---
V
OUT
(S)
x1.024
---
200
400
μA
90
350
-11
+22
40
30
60
40
450
1.2
1
---
---
15
20
---
---
---
---
60
50
mV
80
60
520
1.5
1.4
---
V
3
40
mV
40
93
90
%
KHz
ms
mA
ΔV
OUT1
ΔV
OUT2
f
OSC
t
soft
V
ENH
V
ENL
Load regulation
Oscillation frequency
Soft start time
Power-on voltage of
EN pin
Power-off voltage of
EN pin
Ripple voltage
V
ripple
EFFI
Efficiency
Notes:
1.
V
OUT
(E) Actual output voltage value.
2.
V
OUT
(S) Specified output voltage value.
Datasheet
ES-BYD-WDZCE07D-001
Rev.A/1
Page 3 of 10
BYD Microelectronics Co., Ltd.
BF1210 Series
A
TYPICAL PERFORMANCE CHARACTERISTICS
(T
Ouput Current vs Efficiency
100
95
EFFICIENCY
（
%
）
90
85
80
75
70
65
60
VOUT=5V
= 25°C, unless otherwise noted)
Input Voltage vs Quiescent Current
3
2.5
2
I
Q
(mA)
1.5
1
0.5
0
10000
VOUT=5V
7.4V
12V
10
100
I
OUT
（
mA
）
1000
7
8
9
10
11
V
IN
（
V
）
12
13
14
Input Voltage vs Output Voltage
5.11
5.09
V
OUT
（
V
）
5.07
5.05
5.03
5.01
4.99
4.97
4.95
10
VOUT=5V
0 mA
500 mA
2.0 A
40
35
V
ripple
(mV)
30
25
20
15
10
Input Voltage vs Ripple Voltage
500mA
1A
2A
VOUT=5V
10.5
11 11.5 12 12.5
V
IN
（
V
）
13 13.5 14
7
8
9
10
11 12
V
IN
(V)
13
14
15
Input Voltage vs Power-on Voltage of EN
10
8
V
ENH
（
V
）
6
4
2
0
5
6
7
8
10 11
V
IN
（
V
）
9
12
13
14
Input Voltage vs Power-off Voltage of EN
6
5
V
ENL
（
V
）
4
3
2
1
0
5
6
7
8
10 11
V
IN
（
V
）
9
12
13
14
Datasheet
ES-BYD-WDZCE07D-001
Rev.A/1
Page 4 of 10
BYD Microelectronics Co., Ltd.
BF1210 Series
V
OUT
=5V
V
IN
=12V Soft Start
V
OUT
=5V
V
IN
=7.4V Soft Start
V
OUT
=5V
V
IN
=10V I
OUT
=10mA→500mA
V
OUT
=5V
V
IN
=12V I
OUT
=10mA→500mA
V
OUT
=5V
V
IN
=10V I
OUT
=1A→2A
V
OUT
=5V
V
IN
=12V I
OUT
=1A→2A
Datasheet
ES-BYD-WDZCE07D-001
Rev.A/1
Page 5 of 10
电子工程世界
