Specifications

OBSOLETE
LM3647
SNOS517H –MARCH 2000–REVISED APRIL 2013 www.ti.com
DESCRIPTION (CONTINUED)
When using an external current source, the current is controlled by the LM3647 which turns the current source
on and off. The LM3647 automatically detects the presence of a battery and starts the charging procedure when
the battery is installed. Whenever an error occurs (e.g., short circuit, temperature too high, temperature too low,
bad battery, charge time over, and so on.) the LM3647 will stay in error mode until the battery is removed or it
gets within the allowed charging temperature range. The LM3647 is available in a standard 20-lead SOIC surface
mount package.
CONNECTION DIAGRAM
Figure 1. Top View
See Package SOIC (DW)
Table 1. PIN DESCRIPTIONS
Pin No. Name I/O Description
1 SEL3 I Input to Select Power Source or Li-Ion Cell Voltage
2 SEL4 I Input to Select Maintenance Charge Time Out, Connected to an RC-Network
3 RCIN RC-Timing Pin
4 GND Ground
5 V
CC
5V, Power Supply
6 RESET I Reset Pin, Active Low
7 LED1 O LED Output
8 LED2 O LED Output
9 LED3 O LED Output
10 V
REF
I Voltage Reference Analog Input
11 CEXT External Capacitor
12 CEL I Battery Voltage Input (through resistor divider)
13 CS I Current Sense Input
14 TEMP I NTC-Temperature Sensor Input
15 DISCHG O High when Discharging, Else Low
16 SYSOK O System Monitor Output
17 BUZZER O Buzzer Output
18 PWM O Charge Control Output
19 SEL1 I Tri-Level Input, Discharge/Maintenance Charge Select
20 SEL2 I Tri-Level Input, Battery Type Select (NiCd, NiMH, Li-Ion)
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